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1. Comparing NASA Discovery and New Frontiers Class Mission Concepts for the Io Volcano Observer (IVO)

Author

Hamilton, Christopher W., McEwen, Alfred S., Keszthelyi, Laszlo, Carter, Lynn M., Davies, Ashley G., de Kleer, Katherine, Jessup, Kandis Lea, Jia, Xianzhe, Keane, James T., Mandt, Kathleen, Nimmo, Francis, Paranicas, Chris, Park, Ryan S., Perry, Jason E., Pommier, Anne, Radebaugh, Jani, Sutton, Sarah S., Vorburger, Audrey, Wurz, Peter, Borlina, Cauê, Haapala, Amanda F., DellaGiustina, Daniella N., Denevi, Brett W., Hörst, Sarah M., Kempf, Sascha, Khurana, Krishan K., Likar, Justin J., Masters, Adam, Mousis, Olivier, Polit, Anjani T., Bhushan, Aditya, Bland, Michael, Matsuyama, Isamu, and Spencer, John

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics, Physics - Space Physics
Abstract

Jupiter's moon Io is a highly compelling target for future exploration that offers critical insight into tidal dissipation processes and the geology of high heat flux worlds, including primitive planetary bodies, such as the early Earth, that are shaped by enhanced rates of volcanism. Io is also important for understanding the development of volcanogenic atmospheres and mass-exchange within the Jupiter System. However, fundamental questions remain about the state of Io's interior, surface, and atmosphere, as well as its role in the evolution of the Galilean satellites. The Io Volcano Observer (IVO) would address these questions by achieving the following three key goals: (A) Determine how and where tidal heat is generated inside Io; (B) Understand how tidal heat is transported to the surface of Io; and (C) Understand how Io is evolving. IVO was selected for Phase A study through the NASA Discovery program in 2020 and, in anticipation of a New Frontiers 5 opportunity, an enhanced IVO-NF mission concept was advanced that would increase the Baseline mission from 10 flybys to 20, with an improved radiation design; employ a Ka-band communications to double IVO's total data downlink; add a wide angle camera for color and stereo mapping; add a dust mass spectrometer; and lower the altitude of later flybys to enable new science. This study compares and contrasts the mission architecture, instrument suite, and science objectives for Discovery (IVO) and New Frontiers (IVO-NF) missions to Io, and advocates for continued prioritization of Io as an exploration target for New Frontiers., Comment: Submitted to The Planetary Science Journal for peer-review on 14 August 2024

Published
2024

2. Reflectivity of Venus' dayside disk during the 2020 observation campaign: outcomes and future perspectives

Author

Lee, Yeon Joo, Muñoz, Antonio García, Yamazaki, Atsushi, Quémerais, Eric, Mottola, Stefano, Hellmich, Stephan, Granzer, Thomas, Bergond, Gilles, Roth, Martin, Gallego-Cano, Eulalia, Chaufray, Jean-Yves, Robidel, Rozenn, Murakami, Go, Masunaga, Kei, Kaplan, Murat, Erece, Orhan, Hueso, Ricardo, Kabáth, Petr, Špoková, Magdaléna, Sánchez-Lavega, Agustín, Kim, Myung-Jin, Mangano, Valeria, Jessup, Kandis-Lea, Widemann, Thomas, Sugiyama, Ko-ichiro, Watanabe, Shigeto, Yamada, Manabu, Satoh, Takehiko, Nakamura, Masato, Imai, Masataka, and Cabrera, Juan

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

We performed a unique Venus observation campaign to measure the disk brightness of Venus over a broad range of wavelengths in August and September 2020. The primary goal of the campaign is to investigate the absorption properties of the unknown absorber in the clouds. The secondary goal is to extract a disk mean SO$_2$ gas abundance, whose absorption spectral feature is entangled with that of the unknown absorber at the ultraviolet (UV) wavelengths. A total of 3 spacecraft and 6 ground-based telescopes participated in this campaign, covering the 52 to 1700~nm wavelength range. After careful evaluation of the observational data, we focused on the data sets acquired by 4 facilities. We accomplished our primary goal by analyzing the reflectivity spectrum of the Venus disk over the 283-800 nm wavelengths. Considerable absorption is present in the 350-450 nm range, for which we retrieved the corresponding optical depth by the unknown absorber. The result shows a consistent wavelength dependence of the relative optical depth with that at low latitudes during the Venus flyby by MESSENGER in 2007 (P\'erez-Hoyos et al. 2018), which was expected because the overall disk reflectivity is dominated by low latitudes. Last, we summarize the experience obtained during this first campaign that should enable us to accomplish our second goal in future campaigns., Comment: Accepted for publication in PSJ, 45 pages, 13 figures

Published
2022

3. Priority Questions for Jupiter System Science in the 2020s and Opportunities for Europa Clipper

Author

Sayanagi, Kunio M., Becker, Tracy, Brooks, Shawn, Brueshaber, Shawn, Dahl, Emma, de Pater, Imke, Ebert, Robert, Moutamid, Maryame El, Fletcher, Leigh, Jessup, Kandis Lea, McEwen, Alfred, Molyneux, Philippa M., Moore, Luke, Moses, Julianne, Nénon, Quentin, Orton, Glenn, Paranicas, Christopher, Showalter, Mark, Spilker, Linda, Tiscareno, Matt, Westlake, Joseph, Wong, Michael H., and Young, Cindy

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

This whitepaper identifies important science questions that can be answered through exploration of the Jupiter System, with emphasis on the questions that can be addressed by the Europa Clipper Mission. We advocate for adding Jupiter System Science to the mission after launch when expanding the scientific scope will not affect the development cost., Comment: White Paper submitted to the Astrobiology and Planetary Science Decadal Survey

Published
2020

4. Terrestrial Planets Comparative Climatology (TPCC) mission concept

Author

Tamppari, Leslie K., Brecht, Amanda, Baines, Kevin, Drouin, Brian, Esposito, Larry, Guzewich, Scott, Hofer, Richard, Jessup, Kandis Lea, Kleinböhl, Armin, Kremic, Tibor, Mischna, Michael, Schneider, Nicholas, and Spiga, Aymeric

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

The authors and co-signers of the Terrestrial Planets Comparative Climatology (TPCC) mission concept white paper advocate that planetary science in the next decade would greatly benefit from comparatively studying the fundamental behavior of the atmospheres of Venus and Mars, contemporaneously and with the same instrumentation, to capture atmospheric response to the same solar forcing, and with a minimum of instrument-related variability. Thus, this white paper was created for the 2023-2032 Planetary Science Decadal Survey process. It describes the science rationale for such a mission, and a mission concept that could achieve such a mission., Comment: 8 pages including cover page with one figure on cover page

Published
2020

5. Long-term variations of Venus' 365-nm albedo observed by Venus Express, Akatsuki, MESSENGER, and Hubble Space Telescope

Author

Lee, Yeon Joo, Jessup, Kandis-Lea, Perez-Hoyos, Santiago, Titov, Dmitrij V., Lebonnois, Sebastien, Peralta, Javier, Horinouchi, Takeshi, Imamura, Takeshi, Limaye, Sanjay, Marcq, Emmanuel, Takagi, Masahiro, Yamazaki, Atsushi, Yamada, Manabu, Watanabe, Shigeto, Murakami, Shin-ya, Ogohara, Kazunori, McClintock, William M., Holsclaw, Gregory, and Roman, Anthony

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

An unknown absorber near the cloud top level of Venus generates a broad absorption feature from the ultraviolet (UV) to visible, peaking around 360 nm, and therefore plays a critical role in the solar energy absorption. We present a quantitative study on the variability of the cloud albedo at 365 nm and its impact on Venus' solar heating rates based on an analysis of Venus Express and Akatsuki's UV images, and Hubble Space Telescope and MESSENGER's UV spectral data; in this analysis the calibration correction factor of the UV images of Venus Express (VMC) is updated relative to the Hubble and MESSENGER albedo measurements. Our results indicate that the 365-nm albedo varied by a factor of 2 from 2006 to 2017 over the entire planet, producing a 25-40% change in the low latitude solar heating rate according to our radiative transfer calculations. Thus, the cloud top level atmosphere should have experienced considerable solar heating variations over this period. Our global circulation model calculations show that this variable solar heating rate may explain the observed variations of zonal wind from 2006 to 2017. Overlaps in the timescale of the long-term UV albedo and the solar activity variations make it plausible that solar extreme UV intensity and cosmic-ray variations influenced the observed albedo trends. The albedo variations might also be linked with temporal variations of the upper cloud SO2 gas abundance, which affects the H2SO4-H2O aerosol formation., Comment: 22 pages, 16 figures, accepted

Published
2019
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7. Sulfur Volcanism on Io

Author

Jessup, Kandis Lea, Spencer, John R., and Yelle, Roger

Subjects
Astrophysics
Abstract

In February 2003, March 2003 and January 2004 Pele plume transmission spectra were obtained during Jupiter transit with Hubble's Space Telescope Imaging Spectrograph (STIS), using the 0.1 arcsec long slit and the G230LB grating. The STIS spectra covered the 2100-3100 A wavelength region and extended spatially along Io's limb both northward of Pele. The S2 and SO2 absorption signatures evident in the these data indicate that the gas signature at Pele was temporally variable, and that an S2 absorption signature was present ~ 12 deg. from the Pele vent near 6+/-5 S and 264 +/-15 W, suggesting the presence of another S2 bearing plume on Io. Contemporaneous with the spectral data, UV and visible-wavelength images of the plume were obtained in reflected sunlight with the Advanced Camera for Surveys (ACS) prior to Jupiter transit. The dust scattering recorded in these data provide an additional qualitative measure of plume activity on Io, indicating that the degree of dust scattering over Pele varied as a function of the date of observation, and that there were several other dust bearing plumes active just prior to Jupiter transit. We present constraints on the composition and variability of the gas abundances of the Pele plume as well as the plumes detected by ACS and recorded within the STIS data, as a function of time. We discuss the implications of these results for thermochemical conditions at the plume vents, and our understanding of plume eruption styles active on Io., Comment: pages:44 figures: 7 tables:3

Published
2006
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12. Io’s atmosphere

Author

Lellouch, Emmanuel, McGrath, Melissa A., Jessup, Kandis Lea, Lopes, Rosaly M. C., and Spencer, John R.

Published
2007
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17. Reflectivity of Venus’s Dayside Disk During the 2020 Observation Campaign: Outcomes and Future Perspectives

Author

Lee, Yeon Joo, primary, Muñoz, Antonio García, additional, Yamazaki, Atsushi, additional, Quémerais, Eric, additional, Mottola, Stefano, additional, Hellmich, Stephan, additional, Granzer, Thomas, additional, Bergond, Gilles, additional, Roth, Martin, additional, Gallego-Cano, Eulalia, additional, Chaufray, Jean-Yves, additional, Robidel, Rozenn, additional, Murakami, Go, additional, Masunaga, Kei, additional, Kaplan, Murat, additional, Erece, Orhan, additional, Hueso, Ricardo, additional, Kabáth, Petr, additional, Špoková, Magdaléna, additional, Sánchez-Lavega, Agustín, additional, Kim, Myung-Jin, additional, Mangano, Valeria, additional, Jessup, Kandis-Lea, additional, Widemann, Thomas, additional, Sugiyama, Ko-ichiro, additional, Watanabe, Shigeto, additional, Yamada, Manabu, additional, Satoh, Takehiko, additional, Nakamura, Masato, additional, Imai, Masataka, additional, and Cabrera, Juan, additional

Published
2022
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18. Reflectivity of Venus's Dayside Disk During the 2020 Observation Campaign: Outcomes and Future Perspectives

Author

Física aplicada I, Fisika aplikatua I, Lee, Yeon Joo, García Muñoz, Antonio, Yamazaki, Atsushi, Quémerais, Eric, Mottola, Stefano, Hellmich, Stephan, Granzer, Thomas, Bergond, Gilles, Roth, Martin, Gallego Cano, Eulalia, Chaufray, Jean-Yves, Robidel, Rozenn, Murakami, Go, Masunaga, Kei, Kaplan, Murat, Erece, Orhan, Hueso Alonso, Ricardo, Kabáth, Petr, Špoková, Magdaléna, Sánchez Lavega, Agustín María, Kim, Myung-Jin, Mangano, Valeria, Jessup, Kandis Lea, Widemann, Thomas, Sugiyama, Ko-ichiro, Watanabe, Shigeto, Yamada, Manabu, Satoh, Takehiko, Nakamura, Masato, Imai, Masataka, Cabrera, Juan, Física aplicada I, Fisika aplikatua I, Lee, Yeon Joo, García Muñoz, Antonio, Yamazaki, Atsushi, Quémerais, Eric, Mottola, Stefano, Hellmich, Stephan, Granzer, Thomas, Bergond, Gilles, Roth, Martin, Gallego Cano, Eulalia, Chaufray, Jean-Yves, Robidel, Rozenn, Murakami, Go, Masunaga, Kei, Kaplan, Murat, Erece, Orhan, Hueso Alonso, Ricardo, Kabáth, Petr, Špoková, Magdaléna, Sánchez Lavega, Agustín María, Kim, Myung-Jin, Mangano, Valeria, Jessup, Kandis Lea, Widemann, Thomas, Sugiyama, Ko-ichiro, Watanabe, Shigeto, Yamada, Manabu, Satoh, Takehiko, Nakamura, Masato, Imai, Masataka, and Cabrera, Juan

Abstract

We performed a unique Venus observation campaign to measure the disk brightness of Venus over a broad range of wavelengths in 2020 August and September. The primary goal of the campaign was to investigate the absorption properties of the unknown absorber in the clouds. The secondary goal was to extract a disk mean SO2 gas abundance, whose absorption spectral feature is entangled with that of the unknown absorber at ultraviolet wavelengths. A total of three spacecraft and six ground-based telescopes participated in this campaign, covering the 52–1700 nm wavelength range. After careful evaluation of the observational data, we focused on the data sets acquired by four facilities. We accomplished our primary goal by analyzing the reflectivity spectrum of the Venus disk over the 283–800 nm wavelengths. Considerable absorption is present in the 350–450 nm range, for which we retrieved the corresponding optical depth of the unknown absorber. The result shows the consistent wavelength dependence of the relative optical depth with that at low latitudes, during the Venus flyby by MESSENGER in 2007, which was expected because the overall disk reflectivity is dominated by low latitudes. Last, we summarize the experience that we obtained during this first campaign, which should enable us to accomplish our second goal in future campaigns.

Published
2022

19. Reflectivity of Venus's Dayside Disk During the 2020 Observation Campaign: Outcomes and Future Perspectives

Author

Ministerio de Ciencia e Innovación (España), European Commission, Lee, Yeon Joo, Muñoz, Antonio García, Yamazaki, Atsushi, Quémerais, Eric, Mottola, Stefano, Hellmich, Stephan, Granzer, Thomas, Bergond, Gilles, Roth, Martin, Gallego Cano, Eulalia, Chaufray, Jean-Yves, Robidel, Rozenn, Murakami, Go, Masunaga, Kei s, Kaplan, Murat, Erece, Orhan, Hueso, Ricardo, Kabáth, Petr, Špoková, Magdaléna, Sánchez-Lavega, Agustín, Kim, Myung-Jin, Mangano, Valeria, Jessup, Kandis-Lea, Widemann, Thomas, Sugiyama, Ko-ichiro, Watanabe, Shigeto, Yamada, Manabu, Satoh, Takehiko, Nakamura, Masato, Imai, Masataka se, Cabrera, Juan, Ministerio de Ciencia e Innovación (España), European Commission, Lee, Yeon Joo, Muñoz, Antonio García, Yamazaki, Atsushi, Quémerais, Eric, Mottola, Stefano, Hellmich, Stephan, Granzer, Thomas, Bergond, Gilles, Roth, Martin, Gallego Cano, Eulalia, Chaufray, Jean-Yves, Robidel, Rozenn, Murakami, Go, Masunaga, Kei s, Kaplan, Murat, Erece, Orhan, Hueso, Ricardo, Kabáth, Petr, Špoková, Magdaléna, Sánchez-Lavega, Agustín, Kim, Myung-Jin, Mangano, Valeria, Jessup, Kandis-Lea, Widemann, Thomas, Sugiyama, Ko-ichiro, Watanabe, Shigeto, Yamada, Manabu, Satoh, Takehiko, Nakamura, Masato, Imai, Masataka se, and Cabrera, Juan

Abstract

We performed a unique Venus observation campaign to measure the disk brightness of Venus over a broad range of wavelengths in 2020 August and September. The primary goal of the campaign was to investigate the absorption properties of the unknown absorber in the clouds. The secondary goal was to extract a disk mean SO2 gas abundance, whose absorption spectral feature is entangled with that of the unknown absorber at ultraviolet wavelengths. A total of three spacecraft and six ground-based telescopes participated in this campaign, covering the 52–1700 nm wavelength range. After careful evaluation of the observational data, we focused on the data sets acquired by four facilities. We accomplished our primary goal by analyzing the reflectivity spectrum of the Venus disk over the 283–800 nm wavelengths. Considerable absorption is present in the 350–450 nm range, for which we retrieved the corresponding optical depth of the unknown absorber. The result shows the consistent wavelength dependence of the relative optical depth with that at low latitudes, during the Venus flyby by MESSENGER in 2007, which was expected because the overall disk reflectivity is dominated by low latitudes. Last, we summarize the experience that we obtained during this first campaign, which should enable us to accomplish our second goal in future campaigns. © 2022. The Author(s). Published by the American Astronomical Society.

Published
2022

21. Venus, an Astrobiology Target

Author

Limaye, Sanjay S., primary, Mogul, Rakesh, additional, Baines, Kevin H., additional, Bullock, Mark A., additional, Cockell, Charles, additional, Cutts, James A., additional, Gentry, Diana M., additional, Grinspoon, David H., additional, Head, James W., additional, Jessup, Kandis-Lea, additional, Kompanichenko, Vladimir, additional, Lee, Yeon Joo, additional, Mathies, Richard, additional, Milojevic, Tetyana, additional, Pertzborn, Rosalyn A., additional, Rothschild, Lynn, additional, Sasaki, Satoshi, additional, Schulze-Makuch, Dirk, additional, Smith, David J., additional, and Way, Michael J., additional

Published
2021
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22. Sulfur volcanism on Io

Author

Jessup, Kandis Lea, Spencer, John, and Yelle, Roger

Subjects
Sulfur compounds, Astronomy, Astronomy, Earth sciences
Abstract

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.icarus.2007.06.025 Byline: Kandis Lea Jessup (a), John Spencer (a), Roger Yelle (b) Keywords: Io; Volcanism; Jupiter; satellites Abstract: In February 2003, March 2003 and January 2004 Pele plume transmission spectra were obtained during Jupiter transit with Hubble's Space Telescope Imaging Spectrograph (STIS), using the 0.1a[sup.3] wide slit and the G230LB grating. The STIS spectra covered the 2100-3100 A wavelength regions and extended spatially along Io's limb encompassing the region directly above and northward of the vent of the Pele volcano. The S.sub.2 and SO.sub.2 absorption signatures evident in these data indicate that the gas signature at Pele was temporally variable, and that an S.sub.2 absorption signature was present [approximately equal to]12[degrees] from the Pele vent near 6[+ or -]5 S and 264[+ or -]15 W, suggesting the presence of another S.sub.2 bearing plume on Io. Contemporaneous with the spectral data, UV and visible-wavelength images of the plume were obtained in reflected sunlight with the Advanced Camera for Surveys (ACS) prior to Jupiter transit. The dust scattering recorded in these data provide an additional qualitative measure of plume activity on Io, indicating that the degree of dust scattering over Pele varied as a function of the date of observation, and that there were several other dust bearing plumes active during the observations. We present constraints on the composition and variability of the gas abundances of the Pele plume as well as the plumes detected by ACS and recorded within the STIS data, as a function of time. Author Affiliation: (a) Department of Space Studies, Southwest Research Institute, 1050 Walnut St., Suite 300, Boulder, CO 80302, USA (b) Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85271, USA Article History: Received 14 March 2006; Revised 10 June 2007

Published
2007

23. Mid-infrared detection of large longitudinal asymmetries in Io's S[O.sub.2] atmosphere

Author

Spencer, John R., Lellouch, Emmanuel, Richter, Matthew J., Lopez-Valverde, Miguel A., Jessup, Kandis Lea, Greathouse, Thomas K., and Flaud, Jean-Marie

Subjects
Atmosphere -- Research, Io (Satellite) -- Research, Earth -- Atmosphere, Earth -- Research, Astronomy, Earth sciences
Abstract

We have observed about 16 absorption lines of the [v.sub.2] S[O.sub.2] vibrational band on Io, in disk-integrated 19-[micro]m spectra taken with the TEXES high spectral resolution mid-infrared spectrograph at the NASA Infrared Telescope Facility in November 2001, December 2002, and January 2004. These are the first ground-based infrared observations of Io's sunlit atmosphere, and provide a new window on the atmosphere that allows better longitudinal and temporal monitoring than previous techniques. Dramatic variations in band strength with longitude are seen that are stable over at least a 2 year period. The depth of the strongest feature, a blend of lines centered at 530.42 [cm.sup.-1], varies from about 7% near longitude 180[degrees] to about 1% near longitude 315[degrees] W, as measured at a spectral resolution of 57,000. Interpretation of the spectra requires modeling of surface temperatures and atmospheric density across Io's disk, and the variation in non-LTE [v.sub.2] vibrational temperature with altitude, and depends on the assumed atmospheric and surface temperature structure. About half of Io's 19-[micro]m radiation comes from the Sun-heated surface, and half from volcanic hot spots with temperatures primarily between 150 and 200 K, which occupy about 8% of the surface. The observations are thus weighted towards the atmosphere over these low-temperature hot spots. If we assume that the atmosphere over the hot spots is representative of the atmosphere elsewhere, and that the atmospheric density is a function of latitude, the most plausible interpretation of the data is that the equatorial atmospheric column density varies from about 1.5 x [10.sup.17] [cm.sup.-2] near longitude 180[degrees] W to about 1.5 x [10.sup.16] [cm.sup.-2] near longitude 300[degrees] W, roughly consistent with HST UV spectroscopy and Lyman-[alpha] imaging. The inferred atmospheric kinetic temperature is less than about 150 K, at least on the anti-Jupiter hemisphere where the bands are strongest, somewhat colder than inferred from HST UV spectroscopy and millimeter-wavelength spectroscopy. This longitudinal variability in atmospheric density correlates with the longitudinal variability in the abundance of optically thick, near-UV bright S[O.sub.2] frost. However it is not clear whether the correlation results from volcanic control (regions of large frost abundance result from greater condensation of atmospheric gases supported by more vigorous volcanic activity in these regions) or sublimation control (regions of large frost abundance produce a more extensive atmosphere due to more extensive sublimation). Comparison of data taken in 2001, 2002, and 2004 shows that with the possible exception of longitudes near 180[degrees] W between 2001 and 2002, Io's atmospheric density does not appear to decrease as Io recedes from the Sun, as would be expected if the atmosphere were supported by the sublimation of surface frost, suggesting that the atmosphere is dominantly supported by direct volcanic supply rather than by frost sublimation. However, other evidence such as the smooth variation in atmospheric abundance with latitude, and atmospheric changes during eclipse, suggest that sublimation support is more important than volcanic support, leaving the question of the dominant atmospheric support mechanism still unresolved. Keywords: Io; Atmospheres, Structure; Infrared observations; Radiative transfer; Spectroscopy

Published
2005

24. The atmospheric signature of Io's Prometheus plume and anti-jovian hemisphere: evidence for a sublimation atmosphere

Author

Jessup, Kandis Lea, Spencer, John R., Ballester, Gilda E., Howell, Robert R., Roesler, Fred, Vigel, Miquela, and Yelle, Roger

Subjects
Io (Satellite) -- Research, Astronomy, Earth sciences
Abstract

Using the Hubble Space Telescope's Space Telescope Imaging Spectrograph we have obtained for the first time spatially resolved 2000-3000 [Angstrom] spectra of Io's Prometheus plume and adjoining regions on Io's anti-jovian hemisphere in the latitude range 60[degrees] N-60[degrees] S, using a 0.1' slit centered on Prometheus and tilted roughly 45[degrees] to the spin axis. The S[O.sub.2] column density peaked at 1.25 x [10.sup.17] [cm.sup.-2] near the equator, with an additional 5 x [10.sup.16] [cm.sup.-2] enhancement over Prometheus corresponding to a model volcanic S[O.sub.2] output of [10.sup.5] kg [s.sup.-1]. Apart from the Prometheus peak, the S[O.sub.2] column density dropped fairly smoothly away from the subsolar point, even over regions that included potential volcanic sources. At latitudes less than [+ or -] 30[degrees], the dropoff rate was consistent with control by vapor pressure equilibrium with surface frost with subsolar temperature 117.3 [+ or -] 0.6 K, though S[O.sub.2] abundance was higher than predicted by vapor pressure control at mid-latitudes, especially in the northern hemisphere. We conclude that, at least at low latitudes on the anti-jovian hemisphere where there are extensive deposits of optically-thick S[O.sub.2] frost, the atmosphere is probably primarily supported by sublimation of surface frost. Although the 45[degrees] tilt of our slit prevents us from separating the dependence of atmospheric density on solar zenith angle from its dependence on latitude, the pattern is consistent with a sublimation atmosphere regardless of which parameter is the dominant control. The observed drop in gas abundance towards higher latitudes is consistent with the interpretation of previous Lyman alpha images of Io as indicating an atmosphere concentrated at low latitudes. Comparison with previous disk-resolved UV spectroscopy, Lyman-alpha images, and mid-infrared spectroscopy suggests that Io's atmosphere is denser and more widespread on the anti-jovian hemisphere than at other longitudes. S[O.sub.2] gas temperatures were in the range of 150-250 K over the majority of the anti-jovian hemisphere, consistent with previous observations. SO was not definitively detected in our spectra, with upper limits to the SO/S[O.sub.2] ratio in the range 1-10%, roughly consistent with previous observations. [S.sub.2] gas was not seen anywhere, with an upper limit of 7.5 x [10.sup.14] [cm.sup.-2] for the Prometheus plume, confirming that this plume is significantly poorer in [S.sub.2] than the Pele plume ([S.sub.2]/S[O.sub.2] < 0.005, compared to 0.08-0.3 at Pele). In addition to the gas absorption signatures, we have observed continuum emission in the near ultraviolet (near 2800 [Angstrom]) for the first time. The brightness of the observed emission was directly correlated with the S[O.sub.2] abundance, strongly peaking in the equatorial region over Prometheus. Emission brightness was modestly anti-correlated with the jovian magnetic latitude, decreasing when Io intersected the toms centrifugal equator. Keywords: Io; Satellites; Atmospheres; Spectroscopy

Published
2004

25. Recommendations for Addressing Priority Io Science in the Next Decade

Author

Keane, James, primary, Ahern, Alexandra A., additional, Bagenal, Fran, additional, Mlinar, Amy C. Barr, additional, Basu, Ko, additional, Becerra, Patricio, additional, Bertrand, Tanguy, additional, Beyer, Ross A., additional, Bierson, Carver J., additional, Bland, Michael T., additional, Breuer, Doris, additional, Davies, Ashley G., additional, Kleer, Katherine de, additional, Pater, Imke de, additional, DellaGiustina, Daniella N., additional, Denk, Tilmann, additional, Echevarria, Ariana, additional, Elder, Catherine M., additional, Feaga, Lori M., additional, Grava, Cesare, additional, Gregg, Patricia M., additional, Gregg, Tracy K. P., additional, Hamilton, Christopher W., additional, Harris, Camilla D. K., additional, Harris, Walter M., additional, Hay, Hamish C. F. C., additional, Hendrix, Amanda R., additional, Hörst, Sarah M., additional, Huang, Rowan, additional, Hughes, Andréa C. G., additional, Jessup, Kandis Lea, additional, Jia, Xianzhe, additional, Jozwiak, Lauren M., additional, Keane, James T., additional, Kerber, Laura, additional, Kestay, Laszlo P., additional, Khurana, Krishan K., additional, Kiefer, Walter, additional, Kirchoff, Michelle R., additional, Kite, Edwin S., additional, Klaiber, Lea, additional, Klima, Rachel L., additional, Kling, Corbin L., additional, Lainey, Valery J., additional, Lopes, Rosaly M. C., additional, Lucchetti, Alice, additional, Mandt, Kathleen E., additional, Matsuyama, Isamu, additional, McCarthy, Christine, additional, McEwen, Alfred S., additional, McGrath, Melissa A., additional, Montési, Laurent G. J., additional, Moses, Julieanne I., additional, Moullet, Arielle, additional, Nénon, Quentin, additional, Neumann, Gregory A., additional, Neveu, Marc F., additional, Nimmo, Francis, additional, Noonan, John W., additional, Pajola, Maurizio, additional, Panning, Mark P., additional, Park, Ryan S., additional, Pommier, Anne, additional, Quick, Lynnae C., additional, Radebaugh, Jani, additional, Rathbun, Julie A., additional, Retherford, Kurt D., additional, Roberts, James H., additional, Roussos, Elias, additional, Schenk, Paul M., additional, Schneider, Nick M., additional, Schools, Joe W., additional, Sood, Rohan, additional, Spencer, John R., additional, Spencer, Dan C., additional, Steinbrügge, Gregor, additional, Sulaiman, Ali H., additional, Sutton, Sarah S., additional, Trinh, Antony, additional, Tsang, Constantine C. C., additional, Vertesi, Janet, additional, Vorburger, Audrey, additional, Westlake, Joseph H., additional, and Williams, David A., additional

Published
2021
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27. The Science Case for Io Exploration

Author

Keane, James, primary, Ahern, Alexandra A., additional, Bagenal, Fran, additional, Mlinar, Amy C. Barr, additional, Basu, Ko, additional, Becerra, Patricio, additional, Bertrand, Tanguy, additional, Beyer, Ross A., additional, Bierson, Carver J., additional, Bland, Michael T., additional, Breuer, Doris, additional, Davies, Ashley G., additional, Kleer, Katherine de, additional, Pater, Imke de, additional, DellaGiustina, Daniella N., additional, Denk, Tilmann, additional, Echevarria, Ariana, additional, Elder, Catherine M., additional, Feaga, Lori M., additional, Grava, Cesare, additional, Gregg, Patricia M., additional, Gregg, Tracy K. P., additional, Hamilton, Christopher W., additional, Harris, Camilla D. K., additional, Harris, Walter M., additional, Hay, Hamish C. F. C., additional, Hendrix, Amanda R., additional, Hörst, Sarah M., additional, Huang, Rowan, additional, Hughes, Andréa C. G., additional, Jessup, Kandis Lea, additional, Jia, Xianzhe, additional, Jozwiak, Lauren M., additional, Keane, James T., additional, Kerber, Laura, additional, Kestay, Laszlo P., additional, Khurana, Krishan K., additional, Kiefer, Walter, additional, Kirchoff, Michelle R., additional, Kite, Edwin S., additional, Klaiber, Lea, additional, Klima, Rachel L., additional, Kling, Corbin L., additional, Lainey, Valery J., additional, Lopes, Rosaly M. C., additional, Lucchetti, Alice, additional, Mandt, Kathleen E., additional, Matsuyama, Isamu, additional, McCarthy, Christine, additional, McEwen, Alfred S., additional, McGrath, Melissa A., additional, Montési, Laurent G. J., additional, Moses, Julieanne I., additional, Moullet, Arielle, additional, Nénon, Quentin, additional, Neumann, Gregory A., additional, Neveu, Marc F., additional, Nimmo, Francis, additional, Noonan, John W., additional, Pajola, Maurizio, additional, Panning, Mark P., additional, Park, Ryan S., additional, Pommier, Anne, additional, Quick, Lynnae C., additional, Radebaugh, Jani, additional, Rathbun, Julie A., additional, Retherford, Kurt D., additional, Roberts, James H., additional, Roussos, Elias, additional, Schenk, Paul M., additional, Schneider, Nick M., additional, Schools, Joe W., additional, Sood, Rohan, additional, Spencer, John R., additional, Spencer, Dan C., additional, Steinbrügge, Gregor, additional, Sulaiman, Ali H., additional, Sutton, Sarah S., additional, Trinh, Antony, additional, Tsang, Constantine C. C., additional, Vertesi, Janet, additional, Vorburger, Audrey, additional, Westlake, Joseph H., additional, and Williams, David A., additional

Published
2021
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28. Scientific Exploration of Venus with Aerial Platforms

Author

Cutts, James, primary, Aslam, Shahid, additional, Atreya, Sushil, additional, Baines, Kevin, additional, Beauchamp, Patricia, additional, Bellan, Josette, additional, Bowman, Daniel C., additional, Bugga, Kumar, additional, Bullock, Mark, additional, Byrne, Paul K., additional, Cheung, Kar-Ming, additional, Dyar, Darby, additional, Garcia, Raphael, additional, Grandidier, Jonathan, additional, Grimm, Robert, additional, Grinspoon, David, additional, Jong, Maxim De, additional, Hall, Jeffery, additional, Izraelevitz, Jacob, additional, Jackson, Jennifer M., additional, Jessup, Kandis Lea, additional, Komjathy, Attila, additional, Krishnamoorthy, Siddharth, additional, Lebonnois, Sebastien, additional, McGouldrick, Kevin, additional, Mimoun, David, additional, Mousis, Olivier, additional, Nock, Kerry, additional, O'Rourke, Joseph, additional, Pauken, Michael T., additional, Rabinovitch, Jason, additional, Renard, Jean-Baptiste, additional, Schubert, Gerald, additional, Senske, David, additional, Sotin, Christophe, additional, Thompson, Thomas W., additional, Verdier, Nicolas, additional, Vergados, Panagiotis, additional, Wilson, Colin, additional, and Young, Eliot F., additional

Published
2021
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30. Venus, an Astrobiology Target

Author

Limaye, Sanjay, primary, Bullock, Mark A., additional, Baines, Kevin H., additional, Cockell, Charles, additional, Cordova, Jaime A., additional, Cutts, James A., additional, Gentry, Diana, additional, Grinspoon, David, additional, Head, James, additional, Jessup, Kandis-Lea, additional, Kompanichenko, Vladimir, additional, Lee, Yeon J., additional, Mathies, Richard, additional, Milojevic, Tetyana, additional, Mogul, Rakesh, additional, Pertzborn, Rosalyn A., additional, Rothschild, Lynn, additional, Sasaki, Satoshi, additional, Schulze-Makuch, Dirk, additional, Seager, Sara, additional, Smith, David J., additional, and Way, Michael J., additional

Published
2021
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31. New-Frontiers (NF) Class In-Situ Exploration of Venus: The Venus Climate and Geophysics Mission Concept

Author

Baines, Kevin, primary, Akins, Alexander, additional, Atkinson, David H., additional, Atreya, Sushil, additional, Bullock, Mark, additional, Cheung, Kar-Ming, additional, Cutts, James A., additional, Dorsky, Len, additional, Dyar, Darby, additional, Garcia, Raphael, additional, Grimm, Robert, additional, Jong, Maxim De, additional, Hall, Jeffery, additional, Helbert, Joern, additional, Hunter, Gary, additional, Jessup, Kandis Lea, additional, Kleinboehl, Armin, additional, Komjathy, Attila, additional, Lebonnois, Sebastien, additional, Lognonne, Phillippe, additional, McGouldrick, Kevin, additional, Mimoun, David, additional, Mousis, Olivier, additional, Nikolic, Dragan, additional, O'Rourke, Joseph G., additional, Pauken, Michael T., additional, Renard, Jean-Baptiste, additional, Seager, Sara, additional, Verdier, Nicolas, additional, Vergados, Panagiotis, additional, Wilson, Colin, additional, and Yung, Yuk L., additional

Published
2021
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32. Terrestrial Planets Comparative Climatology (TPCC) mission concept

Author

Tamppari, Leslie, primary, Brecht, Amanda, additional, Baines, Kevin, additional, Drouin, Brian, additional, Esposito, Larry, additional, Guzewich, Scott, additional, Hofer, Richard, additional, Jessup, Kandis Lea, additional, Kleinböhl, Armin, additional, Kremic, Tibor, additional, Mischna, Michael, additional, Schneider, Nicholas, additional, and Spiga, Aymeric, additional

Published
2021
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34. Amateur Ground-based Support of the first BepiColombo flyby of Venus

Author

Garate-Lopez, Itziar, primary, Hueso, Ricardo, additional, Lee, Yeon Joo, additional, Mangano, Valeria, additional, Jessup, Kandis Lea, additional, Peralta, Javier, additional, Sanchez-Lavega, Agustin, additional, Zender, Joe, additional, Benkhoff, Johannes, additional, Murakami, Go, additional, and Scherf, Manuel, additional

Published
2020
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35. Atmospheric Chemistry on Present-Day Venus and Earth: Unresolved Issues and Implications for Extrasolar Planets

Author

Mills, Franklin P., Parkinson, C. D., Jessup, Kandis-Lea, Yung, Yuk L., Marcq, Emmanuel, Vandaele, Ann Carine, Space Science Institute [Boulder] (SSI), University of Michigan [Ann Arbor], University of Michigan System, Southwest Research Institute [Boulder] (SwRI), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), and Cardon, Catherine

Subjects
[SDU] Sciences of the Universe [physics], [SDU]Sciences of the Universe [physics], Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Physics::Geophysics
Abstract

International audience; This presentation provides an overview of the current understanding of Venus' atmospheric chemistry and unresolved issues as well as some important chemical processes on Earth and implications for terrestrial-like extrasolar planets.

Published
2020

36. Intense decadal variations of Venus' UV albedo, and its impact on solar heating rate and atmospheric dynamics

Author

Lee, Yeon Joo, Jessup, Kandis-Lea, Pérez-Hoyos, Santiago, Titov, Dmitrij V., Lebonnois, Sébastien, Peralta, Javier, Horinouchi, Takeshi, Imamura, Takeshi, Limaye, Sanjay, Marcq, Emmanuel, Takagi, Masahiro, Yamazaki, Atsushi, Yamada, Manabu, Watanabe, Shigeto, Murakami, Shin-Ya, Ogohara, Kazunori, Mcclintock, William, Holsclaw, Gregory, Roman, Anthony, University of Tokyo [Kashiwa Campus], Technische Universität Berlin (TU), Southwest Research Institute [Boulder] (SwRI), Departamento de Fisica Aplicada [Bilbao], Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency [Sagamihara] (JAXA), Hokkaido University [Sapporo, Japan], Department of Atmospheric and Oceanic Sciences [Madison], University of Wisconsin-Madison, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Kyoto Sangyo University, Planetary Exploration Research Center [Chiba] (PERC), Chiba Institute of Technology (CIT), Hokkaido Information University, University of Shiga Prefecture, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Space Telescope Science Institute (STSci), and Cardon, Catherine

Subjects
[SDU] Sciences of the Universe [physics], [SDU]Sciences of the Universe [physics]
Abstract

International audience; We report the first quantitative study on the variabil-ity of Venus’ cloud albedo at 365 nm using data ac-quired by four independent space-based instruments.We show a factor of 2 albedo variation had been oc-curred in the past decade. This is sufficient amount toalter solar heating rate at the cloud top level, whichconsequently can affect atmospheric dynamics, i.e.,zonal winds near the cloud top level

Published
2019

37. Intense decadal variation of Venus' 365-nm albedo and its impacts on the atmosphere

Author

Lee, Yeon Joo, Jessup, Kandis Lea, Perez-Hoyos, Santiago, Titov, Dmitrij V., Lebonnois, Sébastien, Peralta, Javier, Horinouchi, Takeshi, Imamura, Takeshi, Limaye, Sanjay S., Marcq, Emmanuel, Takagi, Masahiro, Yamazaki, Atsushi, Yamada, Manabu, Watanabe, Shigeto, Murakami, Shin-Ya, Ogohara, Kazunori, Mcclintock, William, Holsclaw, Greg, Roman, Anthony, University of Tokyo [Kashiwa Campus], Southwest Research Institute [Boulder] (SwRI), Departamento de Fisica Aplicada [Bilbao], Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency [Sagamihara] (JAXA), Hokkaido University [Sapporo, Japan], Graduate School of Frontier Sciences [Kashiwa], The University of Tokyo (UTokyo), Space Science and Engineering Center [Madison] (SSEC), University of Wisconsin-Madison, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Kyoto Sangyo University, Planetary Exploration Research Center [Chiba] (PERC), Chiba Institute of Technology (CIT), Hokkaido Information University, University of Shiga Prefecture, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Space Telescope Science Institute (STSci), and Lebonnois, Sébastien

Subjects
[SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, [SDU.STU.PL] Sciences of the Universe [physics]/Earth Sciences/Planetology, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2019

39. Long-term Variations of Venus’s 365 nm Albedo Observed by Venus Express, Akatsuki, MESSENGER, and the Hubble Space Telescope

Author

Lee, Yeon Joo, primary, Jessup, Kandis-Lea, additional, Perez-Hoyos, Santiago, additional, Titov, Dmitrij V., additional, Lebonnois, Sebastien, additional, Peralta, Javier, additional, Horinouchi, Takeshi, additional, Imamura, Takeshi, additional, Limaye, Sanjay, additional, Marcq, Emmanuel, additional, Takagi, Masahiro, additional, Yamazaki, Atsushi, additional, Yamada, Manabu, additional, Watanabe, Shigeto, additional, Murakami, Shin-ya, additional, Ogohara, Kazunori, additional, McClintock, William M., additional, Holsclaw, Gregory, additional, and Roman, Anthony, additional

Published
2019
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40. Long-term Variations of Venus's 365 nm Albedo Observed by Venus Express, Akatsuki, MESSENGER, and the Hubble Space Telescope

Author

Física aplicada I, Fisika aplikatua I, Lee, Yeon Joo, Jessup, Kandis Lea, Pérez Hoyos, Santiago, Titov, Dmitrij V., Lebonnois, Sebastien, Peralta Calvillo, Javier, Horinouchi, Takeshi, Imamura, Takeshi, Limaye, Sanjay, Marcq, Emmanuel, Takagi, Masahiro, Yamazaki, Atsushi, Yamada, Manabu, Watanabe, Shigeto, Murakami, Shinya, Ogohara, Kazunori, McClintock, William M., Holsclaw, Gregory, Roman, Anthony, Física aplicada I, Fisika aplikatua I, Lee, Yeon Joo, Jessup, Kandis Lea, Pérez Hoyos, Santiago, Titov, Dmitrij V., Lebonnois, Sebastien, Peralta Calvillo, Javier, Horinouchi, Takeshi, Imamura, Takeshi, Limaye, Sanjay, Marcq, Emmanuel, Takagi, Masahiro, Yamazaki, Atsushi, Yamada, Manabu, Watanabe, Shigeto, Murakami, Shinya, Ogohara, Kazunori, McClintock, William M., Holsclaw, Gregory, and Roman, Anthony

Abstract

An unknown absorber near the cloud-top level of Venus generates a broad absorption feature from the ultraviolet (UV) to visible, peaking around 360 nm, and therefore plays a critical role in the solar energy absorption. We present a quantitative study of the variability of the cloud albedo at 365 nm and its impact on Venus's solar heating rates based on an analysis of Venus Express and Akatsuki UV images and Hubble Space Telescope and MESSENGER UV spectral data; in this analysis, the calibration correction factor of the UV images of Venus Express (Venus Monitoring Camera) is updated relative to the Hubble and MESSENGER albedo measurements. Our results indicate that the 365 nm albedo varied by a factor of 2 from 2006 to 2017 over the entire planet, producing a 25%-40% change in the low-latitude solar heating rate according to our radiative transfer calculations. Thus, the cloud-top level atmosphere should have experienced considerable solar heating variations over this period. Our global circulation model calculations show that this variable solar heating rate may explain the observed variations of zonal wind from 2006 to 2017. Overlaps in the timescale of the long-term UV albedo and the solar activity variations make it plausible that solar extreme UV intensity and cosmic-ray variations influenced the observed albedo trends. The albedo variations might also be linked with temporal variations of the upper cloud SO2 gas abundance, which affects the H2SO4-H2O aerosol formation.

Published
2019

41. Insights on Venus’Cloud Top Chemistry, Convective Activity and Topographyfrom HST

Author

Jessup, Kandis-Lea, Marcq, Emmanuel, Bertaux, Jean-Loup, Mills, Franklin P., Limaye, Sanjay, Roman, Anthony, Cardon, Catherine, Southwest Research Institute [Boulder] (SwRI), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Australian National University (ANU), Space Science Institute [Boulder] (SSI), University of Wisconsin-Madison, and Space Telescope Science Institute (STSci)

Subjects
[SDU] Sciences of the Universe [physics], [SDU]Sciences of the Universe [physics]
Abstract

International audience; Based on the HSTobserved LST and latitude albedo variations we conclude that topography impacts the vertical distribution of Venus’ unidentified absorber(s) through both large and small-scale mixing processes. As this (these) species have a direct impact on Venus’ radiative balance, climate and cloud super-rotation, we strongly advocate for future observations that can uniquely and contemporaneously characterize Venus’ cloud top albedo and chemistry relative to Venus’ underlying surface topography and zonal cloud motions

Published
2018

43. Atmospheric chemistry on Venus: An overview of unresolved issues

Author

Mills, Franklin, Marcq, Emmanuel, Yung, Yuk, Parkinson, Christopher, Jessup, Kandis Lea, Vandaele, Ann Carine, Mills, Franklin, Marcq, Emmanuel, Yung, Yuk, Parkinson, Christopher, Jessup, Kandis Lea, and Vandaele, Ann Carine

Abstract

Venus' atm. is 96.5% CO_2 and 3.5% N_2 with trace abundances of SO_2, OCS, H_2O, HCl, HF, and HBr, as well as their photochem. and lightning-induced products. The global clouds are composed at least partly of concd. sulfuric acid. The surface pressure is 90 atm and surface temps. exceed 700 K. Atm. chem. transitions from ion chem. through photochem. to thermal equil. chem. with heterogeneous chem. likely throughout the atm. Three major chem. cycles have been identified: the carbon dioxide, sulfur oxidn., and polysulfur cycles. The carbon dioxide cycle includes CO_2 photolysis, transport of a significant fraction of CO and O to the night side, prodn. of O_2, and conversion of CO and O_2 to CO_2, possibly via chlorine catalyzed pathways. The sulfur oxidn. cycle comprises transport upward of OCS, SO_2, and H_2O, oxidn. to H_2SO_4, condensation to form the global 30-km thick cloud layers, and sulfuric acid rain. The polysulfur cycle involves the upward transport of OCS and SO_2, disproportionation and prodn. of S_x (x=2-8), and downward transport of S_x to react with CO and SO_3. There is solid evidence for the carbon dioxide and sulfur oxidn. cycles; the polysulfur cycle is more speculative but plausible. Alternatively, sulfur chem. on Venus has been conceptually divided into fast and slow atm. cycles and a geol. cycle. Recent work (Parkinson et al, PSS, 2015) suggests the ternary SO_2-H_2O-H_2SO_4 system may bifurcate depending on the relative abundances of H_2O and SO_2. Despite this general understanding, five decades of spacecraft, and 200 years of observation, numerous significant unresolved issues remain. One is the means by which CO_2 is stabilized over geol. time - models predict O_2 abundances a factor of ten larger than the observational upper limit. Another is the lack of consistency among models of the chem. and microphysics in different regions, esp. in the cloud layers, where the mixing ratios of many important trace species change by orders of magnitude

Published
2018

44. Venus : Observe it while it's hot !

Author

Jessup, Kandis Lea, Mills, Frank, Limaye, Sanjay, Marcq, Emmanuel, Bertaux, Jean-Loup, Wilson, Colin, Imamura, T., Nakamura, M., Southwest Research Institute [Boulder] (SwRI), Space Science Institute [Boulder] (SSI), University of Wisconsin-Madison, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Clarendon Laboratory [Oxford], University of Oxford [Oxford], Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency [Sagamihara] (JAXA), and University of Oxford

Subjects
[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]
Abstract

International audience; Venus' global-scale cloud and haze layers are composed of complexes of sulfuric acid (H2SO4) and water. Because the clouds play a critical role in Venus' energy balance and long-term climate evolution , accurate definition of their formation process is a high priority in Venus atmospheric studies. On a basic level it is understood that the H2SO4 clouds and haze form via the combination of SO3 and H2O, and SO3 forms via oxidation of SO2. Thus, sulfur-bearing and sulfur-oxidized species, such as SO2, SO, S, OCS, H2SO4, are key traces of Venus' H2SO4 cloud/haze formation process. However, the specific pathways (which may be chemical, micro-physical and/or dynamical) that balance the budget of sulfur (and oxidized sulfur) in Venus' atmosphere are ill-defined [1-3], as are the mechanisms that sustain the density of the clouds. As result, Venus' climate evolution is ill-defined, and understanding Venus' sulfur-budget is highlighted as an important Venus exploration target.

Published
2016

45. Advancing Venus Atmospheric Modeling via Coordinated HST-Akatsuki Observations

Author

Jessup, Kandis Lea, Imamura, Takeshi, Nakamura, M., Mills, Franklin, Marcq, Emmanuel, Limaye, Sanjay, Wilson, Colin, Bertaux, Jean-Loup, Young, Eliot, Kremic, Tibor, Southwest Research Institute [Boulder] (SwRI), Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency [Sagamihara] (JAXA), Space Science Institute [Boulder] (SSI), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Wisconsin-Madison, Clarendon Laboratory [Oxford], University of Oxford [Oxford], NASA Glenn Research Center, NASA, and University of Oxford

Subjects
[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]
Abstract

International audience; Venus' global-scale H2SO4 cloud and haze layers form via the combination of SO3 and H2O, and SO3 forms via oxidation of SO2. Sulfur-bearing and sulfur-oxidized species, such as SO2 , SO, S, OCS, H2 O4 , are key traces of Venus' H2SO4 cloud/haze formation process. These species are also important tracers of the ongoing chemical evolution of Venus' atmosphere, atmospheric dynamics, and the level/history of active volcanism occurring on the planet. However, the specific pathways (which may be chemical, microphysical and/or dynamical) that balance the budget of sulfur (and oxidized sulfur) in Venus' atmosphere are ill-defined, as are the mechanisms that sustain the density of the clouds. As result, Venus' climate evolution is ill-defined, and understanding Venus' sulfur-budget is highlighted as an important Venus exploration target.

Published
2016

48. High-spectral resolution mid-UV spectrograph for Venus observing

Author

Jessup, Kandis Lea, Woodruff, Robert A., Davis, M., Beebe, Chip, Finley, Tiffany, Marcq, Emmanuel, Mills, F., Bertaux, Jean-Loup, Southwest Research Institute [Boulder] (SwRI), Center for Astrophysics and Space Astronomy [Boulder] (CASA), University of Colorado [Boulder], Southwest Research Institute [San Antonio] (SwRI), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Space Science Institute [Boulder] (SSI), and Cardon, Catherine

Subjects
[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]
Abstract

International audience; Investigating Venus' sulphur-oxide chemical cycle is highlighted as an important science target for Venus exploration because this cycle impacts radiative balance in Venus' atmosphere. In particular, it determines the abundance of S, O, SO, SO2 , and SO3 in the atmosphere; and it is the abundance of these species along with H2O that determines the rate of formation of the H2SO4 clouds that enshroud the planet. Additionally, the unknown UV absorber, which is expected to be responsible for more than 50% of the energy deposited to Venus mesosphere, is anticipated to be a sulphur-bearing compound [1], and its abundance is also expected to be linked to the sulphur-oxide cycle. Required Measurement: The two species that most directly map to the mechanisms that drive the sulfur-oxide cycle are the SO2 and SO gas species. Direct and simultaneous observation of the spatial distribution of these species as a function of local time, latitude and cloud motion in Venus' atmosphere can only be done below the clouds via in-situ observation. However, above the clouds these distributions can be derived from spectroscopic observations obtained in the mid-UV (between 190-240 nm) where the gas signatures of the two gases are isolated from the absorption signatures of other constituents prominent in Venus' atmosphere. Notably, at these wavelengths the absorption signatures of the two gases are strongly but not completely overlapping; to disentangle the bandheads of the 10Ȧ wide gas absorption bands, it is necessary to have both spectral sampling and the resolution of the sampling ≤ 2Ȧ. We are working to develop a compact & lightweight mid-UV spectrograph that will have sufficient spectral resolution (1.5 Ȧ) to segregate the gas signatures of the two gases and that can obtain reasonable spatial resolution of the planet disk from orbit around Venus as well as from a highly elliptical (perigee ~ 75000 km) Earth orbit. The spectral resolution of the proposed spectrograph will be 10x higher than that achieved by the UVS flown on the Pioneer Venus Orbiter, which was launched in 1978 [2]; and in fact, would be 10x higher than that acquired with any of the spectrographs flown to Venus within the last 40 years [3].The development and use of this type of UV spectrograph for space flight is long overdue , since in the most recent space-mission history the only UV spectrographs that have been flown in inter-planetary space with sensitivity to the 190-240 nm wavelength region are the Galileo UVS (15Ȧ spectral resolution) which was developed in the 1980s based on Voyager [4] the SPICAV and SPICAM instruments which aslo obtained 15Ȧ spectral resolution, and were included in the Venus and Mars Express payloads, respectively [3,5]; the MASCS/UVVS (50 Ȧ spectral resolution) included on the Messenger payload [6]; and the IUVS (5Ȧ spectral resolution) included on the MAVEN payload launched November 2013 [7]. References

Published
2015

49. Simulations of Vertical Profiles of SO and SO2 in Venus’ Mesosphere

Author

Mills, Franklin, Jessup, Kandis Lea, Yung, Yuk L., Mills, Franklin, Jessup, Kandis Lea, and Yung, Yuk L.

Abstract

The primary reservoir for SO2 on Venus lies in the troposphere, but a pronounced SO2 inversion layer has been consistently observed my multiple instruments since modern observations began in 2004. The Caltech/JPL photochemical model with simplified standard chemistry was used to calculate steady-state vertical profiles for SO2 as a function of solar zenith angle at 58–110 km altitude. Assuming photochemistry ceases at each altitude at the solar zenith angle where the photochemical lifetime equals the zonal transport lifetime, an estimate of the actual non-steady-state vertical profile at the evening terminator has been constructed for the equatorial region. The resultant profile has a factor of two increase in the SO2 mixing ratio from 70 to 80 km altitude. This agrees qualitatively but not quantitatively with the observations, which suggests the interaction of photochemistry and dynamics may be important for creating the observed mesospheric SO2 inversion layer.

Published
2017

50. Dynamics and chemistry of Venus' large and complex cloud system : a science case for an in-situ long-term chemical laboratory

Author

Widemann, Thomas, Määttänen, Anni, Wilquet, Valérie, Mcgouldrick, Kevin, Jessup, Kandis Lea, Wilson, Colin, Limaye, Sanjay, Eurovenus Consortium, The, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Southwest Research Institute [Boulder] (SwRI), Department of Atmospheric, Oceanic and Planetary Physics [Oxford] (AOPP), University of Oxford [Oxford], Department of Physics [Madison], University of Wisconsin-Madison, University of Oxford, Laboratoire d'études spatiales et d'instrumentation en astrophysique ( LESIA ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), IMPEC - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales ( LATMOS ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique ( BIRA-IASB ), Laboratory for Atmospheric and Space Physics [Boulder] ( LASP ), University of Colorado Boulder [Boulder], Southwest Research Institute [Boulder] ( SwRI ), Department of Atmospheric, Oceanic and Planetary Physics [Oxford] ( AOPP ), University of Wisconsin-Madison [Madison], and Cardon, Catherine

Subjects
[PHYS.ASTR.EP] Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [ PHYS.ASTR.EP ] Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [ SDU.ASTR.EP ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]
Abstract

The planet Venus is the closest to the planet Earth both geographically and geometrically, with an average solar distance only 0.3AU smaller than that of Earth and an equatorial radius that is only 5% smaller than Earth's. But the similarities appear to end there. How did the environments of Venus and Earth become so divergent? The answer to this question relies upon an understanding of Venus' origins, the nature of its present atmosphere, and the role that the clouds have played in evolution and current state of Venus. Venus' clouds are composed of highly concentrated solutions of sulfuric acid and water. The sulfuric acid is produced photochemically from reactions involving water vapor and various sulfur species such as SO2 in the upper atmosphere around 62 km. The region from 50-60 km altitude is convectively unstable, suggesting that most of the cloud formation here is convectively driven, as are cumulus clouds on Earth but with sulfuric acid taking the place of water as the main condensable species. The clouds of Venus are ubiquitous, play a significant role in the radiative balance of the planet, are used as tracers to probe the atmospheric circulation, and are a key part of a global sulfurohydrological cycle that redistributes key greenhouse gasses such as SO2 and H2O. Thus understanding the clouds of Venus holds the key to understanding how Venus itself came to be the world of extremes that it is today. ESA's Venus Express mission, launched in Nov. 2005, has significantly improved our knowledge about the atmosphere of Venus by providing global long-term remote sensing observations with complete coverage in latitude and local solar time. However major questions remain about key minor species and how they vary throughout the major atmospheric regimes in the upper atmosphere, near the cloud tops where photolysis and condensation processes occur, near the surface where coupling and interchange with the atmosphere occurs, and in the middle atmosphere where they combine through meso-scale convection. In situ sampling of these aerosols represents a key measurement for constraining their properties, and identifying their role in the sulfurohydrological cycle by means of microphysical models of steadily increasing complexity. A probe/lander making a single descent will lack the spatial, temporal and local time coverage to address the coupling of compositional variations with radiative and dynamical properties of the atmosphere at cloud level, requiring a long duration flight. Establishing a long-term chemical laboratory in the cloud layer which would measure the detailed composition of both gas and liquid phases, and their latitudinal, diurnal and vertical variability using a combination of mass spectrometry, gas chromatography, tunable laser transmission spectrometry, and polar nephelometry would significantly address all of these objectives. It would allow the determination of the size distribution, shape, and real and imaginary refractive indices of the cloud particles, and the measurement of intensity and polarization phase functions. Our target species would include those known to be associated with cloud formation (e.g. H2SO4, SO3, SO2, H2O), as well as species important in stratospheric chemistry (e.g. CO, ClCOx, Ox, HCl, HF) and surface-atmosphere buffering (e.g. CO, OCS, SOx, Ox, H2S).

Published
2014

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