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424 results on '"Cowan, Nicolas B."'

151. Integrated photonic-based coronagraphic systems for future space telescopes

Author

Ruane, Garreth J., Desai, Niyati, König, Lorenzo, Por, Emiel, Juanola-Parramon, Roser, Belikov, Ruslan, Laginja, Iva, Guyon, Olivier, Pueyo, Laurent, Fogarty, Kevin, Absil, Olivier, Altinier, Lisa, Baudoz, Pierre, Bidot, Alexis, Bonse, Markus Johannes, Bott, Kimberly, Brandl, Bernhard, Carlotti, Alexis, Casewell, Sarah L., Choquet, Elodie, Cowan, Nicolas B., Doelman, David, Fowler, J., Gebhard, Timothy D., Gutierrez, Yann, Haffert, Sebastiaan Y., Herscovici-Schiller, Olivier, Hours, Adrien, Kenworthy, Matthew, Kleisioti, Elina, Krasteva, Mariya, Landman, Rico, Leboulleux, Lucie, Mazoyer, Johan, Millar-Blanchaer, Maxwell A., Mouillet, David, N'Diaye, Mamadou, Snik, Frans, van Dam, Dirk, van Gorkom, Kyle, van Kooten, Maaike, and Vaughan, Sophia R.

Published
2023
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152. Visible extreme adaptive optics on extremely large telescopes: towards detecting oxygen in Proxima Centauri b and analogs

Author

Ruane, Garreth J., Fowler, J., Haffert, Sebastiaan Y., van Kooten, Maaike A. M., Landman, Rico, Bidot, Alexis, Hours, Adrien, N'Diaye, Mamadou, Absil, Olivier, Altinier, Lisa, Baudoz, Pierre, Belikov, Ruslan, Bonse, Markus Johannes, Bott, Kimberly, Brandl, Bernhard, Carlotti, Alexis, Casewell, Sarah L., Choquet, Elodie, Cowan, Nicolas B., Desai, Niyati, Doelman, David, Fogarty, Kevin, Gebhard, Timothy D., Gutierrez, Yann, Guyon, Olivier, Herscovici-Schiller, Olivier, Juanola-Parramon, Roser, Kenworthy, Matthew, Kleisioti, Elina, König, Lorenzo, Krasteva, Mariya, Laginja, Iva, Leboulleux, Lucie, Mazoyer, Johan, Millar-Blanchaer, Maxwell A., Mouillet, David, Por, Emiel, Pueyo, Laurent, Snik, Frans, van Dam, Dirk, van Gorkom, Kyle, and Vaughan, Sophia R.

Published
2023
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153. CO or no CO? Narrowing the CO abundance constraint and recovering the H2O detection in the atmosphere of WASP-127 b using SPIRou.

Author

Boucher, Anne, Lafreniére, David, Pelletier, Stefan, Darveau-Bernier, Antoine, Radica, Michael, Allart, Romain, Artigau, Étienne, Cook, Neil J, Debras, Florian, Doyon, René, Gaidos, Eric, Benneke, Björn, Cadieux, Charles, Carmona, Andres, Cloutier, Ryan, Cortés-Zuleta, Pía, Cowan, Nicolas B, Delfosse, Xavier, Donati, Jean-François, and Fouqué, Pascal

Subjects
ORIGIN of planets, NATURAL satellite atmospheres, SPACE telescopes, ATMOSPHERE, NATURAL satellites
Abstract

Precise measurements of chemical abundances in planetary atmospheres are necessary to constrain the formation histories of exoplanets. A recent study of WASP-127 b, a close-in puffy sub-Saturn orbiting its solar-type host star in 4.2 d, using Hubble Space Telescope (HST) and Spitzer revealed a feature-rich transmission spectrum with strong excess absorption at 4.5 μm. However, the limited spectral resolution and coverage of these instruments could not distinguish between CO and/or CO2 absorption causing this signal, with both low and high C/O ratio scenarios being possible. Here we present near-infrared (0.9–2.5 μm) transit observations of WASP-127 b using the high-resolution SPIRou spectrograph, with the goal to disentangle CO from CO2 through the 2.3 μm CO band. With SPIRou, we detect H2O at a t -test significance of 5.3 σ and observe a tentative (3σ) signal consistent with OH absorption. From a joint SPIRou + HST + Spitzer retrieval analysis, we rule out a CO-rich scenario by placing an upper limit on the CO abundance of log10[CO] <−4.0, and estimate a log10[CO2] of −3.7 |$^{+0.8}_{-0.6}$| , which is the level needed to match the excess absorption seen at 4.5 μm. We also set abundance constraints on other major C-, O-, and N-bearing molecules, with our results favouring low C/O (0.10 |$^{+0.10}_{-0.06}$|), disequilibrium chemistry scenarios. We further discuss the implications of our results in the context of planet formation. Additional observations at high and low resolution will be needed to confirm these results and better our understanding of this unusual world. [ABSTRACT FROM AUTHOR]

Published
2023
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157. GJ 1252b: A Hot Terrestrial Super-Earth with No Atmosphere

Author

Crossfield, Ian J. M., primary, Malik, Matej, additional, Hill, Michelle L., additional, Kane, Stephen R., additional, Foley, Bradford, additional, Polanski, Alex S., additional, Coria, David, additional, Brande, Jonathan, additional, Zhang, Yanzhe, additional, Wienke, Katherine, additional, Kreidberg, Laura, additional, Cowan, Nicolas B., additional, Dragomir, Diana, additional, Gorjian, Varoujan, additional, Mikal-Evans, Thomas, additional, Benneke, Björn, additional, Christiansen, Jessie L., additional, Deming, Drake, additional, and Morales, Farisa Y., additional

Published
2022
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158. TOI-1452 b: SPIRou and TESS Reveal a Super-Earth in a Temperate Orbit Transiting an M4 Dwarf

Author

Cadieux, Charles, primary, Doyon, René, additional, Plotnykov, Mykhaylo, additional, Hébrard, Guillaume, additional, Jahandar, Farbod, additional, Artigau, Étienne, additional, Valencia, Diana, additional, Cook, Neil J., additional, Martioli, Eder, additional, Vandal, Thomas, additional, Donati, Jean-François, additional, Cloutier, Ryan, additional, Narita, Norio, additional, Fukui, Akihiko, additional, Hirano, Teruyuki, additional, Bouchy, François, additional, Cowan, Nicolas B., additional, Gonzales, Erica J., additional, Ciardi, David R., additional, Stassun, Keivan G., additional, Arnold, Luc, additional, Benneke, Björn, additional, Boisse, Isabelle, additional, Bonfils, Xavier, additional, Carmona, Andrés, additional, Cortés-Zuleta, Pía, additional, Delfosse, Xavier, additional, Forveille, Thierry, additional, Fouqué, Pascal, additional, da Silva, João Gomes, additional, Jenkins, Jon M., additional, Kiefer, Flavien, additional, Kóspál, Ágnes, additional, Lafrenière, David, additional, Martins, Jorge H. C., additional, Moutou, Claire, additional, do Nascimento, J.-D., additional, Ould-Elhkim, Merwan, additional, Pelletier, Stefan, additional, Twicken, Joseph D., additional, Bouma, Luke G., additional, Cartwright, Scott, additional, Darveau-Bernier, Antoine, additional, Grankin, Konstantin, additional, Ikoma, Masahiro, additional, Kagetani, Taiki, additional, Kawauchi, Kiyoe, additional, Kodama, Takanori, additional, Kotani, Takayuki, additional, Latham, David W., additional, Menou, Kristen, additional, Ricker, George, additional, Seager, Sara, additional, Tamura, Motohide, additional, Vanderspek, Roland, additional, and Watanabe, Noriharu, additional

Published
2022
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163. A New Analysis of Eight Spitzer Phase Curves and Hot Jupiter Population Trends: Qatar-1b, Qatar-2b, WASP-52b, WASP-34b, and WASP-140b

Author

May, E. M., primary, Stevenson, K. B., additional, Bean, Jacob L., additional, Bell, Taylor J., additional, Cowan, Nicolas B., additional, Dang, Lisa, additional, Desert, Jean-Michel, additional, Fortney, Jonathan J., additional, Keating, Dylan, additional, Kempton, Eliza M.-R., additional, Komacek, Thaddeus D., additional, Lewis, Nikole K., additional, Mansfield, Megan, additional, Morley, Caroline, additional, Parmentier, Vivien, additional, Rauscher, Emily, additional, Swain, Mark R., additional, Zellem, Robert T., additional, and Showman, Adam, additional

Published
2022
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164. K2 and Spitzer phase curves of the rocky ultra-short-period planet K2-141 b hint at a tenuous rock vapor atmosphere

Author

Zieba, Sebastian, Zilinskas, Mantas, Kreidberg, Laura, Nguyen, T. Giang, Miguel, Yamila, Cowan, Nicolas B., Pierrehumbert, Raymond, Carone, Ludmila, Dang, Lisa, Hammond, Mark, Louden, Tom, Lupu, Roxana, Malavolta, Luca, and Stevenson, Kevin B.

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Planets and satellites: individual: K2-141 b, Spitzer, planets and satellites: atmospheres, planets and satellites: individual: K2-141 b, techniques: photometric, Exoplanets, K2-141 b, lava planet, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Space and Planetary Science, atmospheres, Astrophysics::Solar and Stellar Astrophysics, Planets and satellites: atmospheres, Astrophysics::Earth and Planetary Astrophysics, Techniques: photometric, Astrophysics - Earth and Planetary Astrophysics
Abstract

K2-141 b is a transiting, small (1.5 Re) ultra-short-period (USP) planet discovered by Kepler orbiting a K-dwarf host star every 6.7 hours. The planet's high surface temperature makes it an excellent target for thermal emission observations. Here we present 65 hours of continuous photometric observations of K2-141 b collected with Spitzer's IRAC Channel 2 at 4.5 micron spanning 10 full orbits of the planet. We measure an infrared eclipse depth of 143 +/- 39 ppm and a peak to trough amplitude variation of 121 +/- 43 ppm. The best fit model to the Spitzer data shows no significant thermal hotspot offset, in contrast to the previously observed offset for the well-studied USP planet 55 Cnc e. We also jointly analyze the new Spitzer observations with the photometry collected by Kepler during two separate K2 campaigns. We model the planetary emission with a range of toy models that include a reflective and a thermal contribution. With a two-temperature model, we measure a dayside temperature of 2049 +/- 361 K and a night-side temperature that is consistent with zero (Tp,n < 1712 K at 2 sigma). Models with a steep dayside temperature gradient provide a better fit to the data than a uniform dayside temperature (DeltaBIC = 22.2). We also find evidence for a non-zero geometric albedo Ag = 0.28 +/- 0.07. We also compare the data to a physically motivated, pseudo-2D rock vapor model and a 1D turbulent boundary layer model. Both models fit the data well. Notably, we find that the optical eclipse depth can be explained by thermal emission from a hot inversion layer, rather than reflected light. A thermal inversion may also be responsible for the deep optical eclipse observed for another USP, Kepler-10 b. Finally, we significantly improve the ephemerides for K2-141 b and c, which will facilitate further follow-up observations of this interesting system with state-of-the-art observatories like JWST., 31 pages, 27 figures, 12 tables, accepted for publication in A&A

Published
2022

166. Thermal Phase Curves of XO-3b: An Eccentric Hot Jupiter at the Deuterium Burning Limit

Author

Dang, Lisa, primary, Bell, Taylor J., additional, Cowan, Nicolas B., additional, Thorngren, Daniel, additional, Kataria, Tiffany, additional, Knutson, Heather A., additional, Lewis, Nikole K., additional, Stassun, Keivan G., additional, Fortney, Jonathan J., additional, Agol, Eric, additional, Laughlin, Gregory P., additional, Burrows, Adam, additional, Collins, Karen A., additional, Deming, Drake, additional, Jovmir, Diana, additional, Langton, Jonathan, additional, Rastegar, Sara, additional, and Showman, Adam P., additional

Published
2021
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169. Deep Two-phase, Hemispherical Magma Oceans on Lava Planets.

Author

Boukaré, Charles-Édouard, Cowan, Nicolas B., and Badro, James

Subjects
*MAGMAS, *LAVA, *PLANETS, *PLANETARY surfaces, *PLANETARY interiors, *LUNAR craters, *EXTRASOLAR planets
Abstract

Astronomers have discovered a handful of exoplanets with rocky bulk compositions but orbiting that orbit so close to their host star that the surface of the planet must be at least partially molten. It is expected that the dayside of such “lava planets” harbors a rock-vapor atmosphere that flows quickly toward the airless nightsideâ€"this partial atmosphere is critical to the interpretation of lava planet observations, but transports negligible heat toward the nightside. As a result, the surface temperature of the magma ocean may range from 3000 K near the substellar point down to 1500 K near the dayâ€"night terminator. We use simple models incorporating the thermodynamics and geochemistry of partial melt to predict the physical and chemical properties of the magma ocean as a function of the distance from the substellar point. Our principal findings are that: (1) the dayside magma ocean is much deeper than previously thought, probably extending down to the coreâ€"mantle boundary below the substellar point of an Earth-sized planet; (2) much of the dayside is only partially molten, leading to gradients in the surface chemistry of the magma ocean; and (3) the temperature at the base of the silicate mantle is as important as the surface temperature. In the most extreme cases, lava planet interiors could be cold enough such that thermal stratification below the substellar point is gravitationally stable. These findings have important implications for the dynamics of the magma ocean, as well as the composition and dynamics of the atmosphere. [ABSTRACT FROM AUTHOR]

Published
2022
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170. impact of ultraviolet heating and cooling on the dynamics and observability of lava planet atmospheres.

Author

Nguyen, T Giang, Cowan, Nicolas B, Pierrehumbert, Raymond T, Lupu, Roxana E, and Moores, John E

Subjects
*PLANETARY atmospheres, *TURBULENT boundary layer, *TEMPERATURE inversions, *LAVA, *ATMOSPHERIC circulation, *LUNAR craters
Abstract

Lava planets have non-global, condensible atmospheres similar to icy bodies within the Solar system. Because they depend on interior dynamics, studying the atmospheres of lava planets can lead to understanding unique geological processes driven by their extreme environment. Models of lava planet atmospheres have thus far focused on either radiative transfer or hydrodynamics. In this study, we couple the two processes by introducing ultraviolet (UV) and infrared (IR) radiation to a turbulent boundary layer model. We also test the effect of different vertical temperature profiles on atmospheric dynamics. Results from the model show that UV radiation affects the atmosphere much more than IR. UV heating and cooling work together to produce a horizontally isothermal atmosphere away from the substellar point regardless of the vertical temperature profile. We also find that stronger temperature inversions induce stronger winds and hence cool the atmosphere. Our simulated transmission spectra of the bound atmosphere show a strong SiO feature in the UV that would be challenging to observe in the planet's transit spectrum due to the precision required. Our simulated emission spectra are more promising, with significant SiO spectral features at 4.5 and 9 |$\mu$| m that can be observed with the James Webb Space Telescope. Different vertical temperature profiles produce discernible dayside emission spectra, but not in the way one would expect. [ABSTRACT FROM AUTHOR]

Published
2022
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171. A comprehensive reanalysis of Spitzer’s 4.5 μm phase curves, and the phase variations of the ultra-hot Jupiters MASCARA-1b and KELT-16b

Author

Bell, Taylor J, primary, Dang, Lisa, additional, Cowan, Nicolas B, additional, Bean, Jacob, additional, Désert, Jean-Michel, additional, Fortney, Jonathan J, additional, Keating, Dylan, additional, Kempton, Eliza, additional, Kreidberg, Laura, additional, Line, Michael R, additional, Mansfield, Megan, additional, Parmentier, Vivien, additional, Stevenson, Kevin B, additional, Swain, Mark, additional, and Zellem, Robert T, additional

Published
2021
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172. A survey of exoplanet phase curves with Ariel

Author

Charnay, Benjamin, primary, Mendonça, João M., additional, Kreidberg, Laura, additional, Cowan, Nicolas B., additional, Taylor, Jake, additional, Bell, Taylor J., additional, Demangeon, Olivier, additional, Edwards, Billy, additional, Haswell, Carole A., additional, Morello, Giuseppe, additional, Mugnai, Lorenzo V., additional, Pascale, Enzo, additional, Tinetti, Giovanna, additional, Tremblin, Pascal, additional, and Zellem, Robert T., additional

Published
2021
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173. Keys of a Mission to Uranus or Neptune, the Closest Ice Giants

Author

Guillot, Tristan, primary, Fortney, Jonathan, additional, Rauscher, Emily, additional, Marley, Mark S., additional, Parmentier, Vivien, additional, Line, Mike, additional, Wakeford, Hannah, additional, Kaspi, Yohai, additional, Helled, Ravit, additional, Ikoma, Masahiro, additional, Knutson, Heather, additional, Menou, Kristen, additional, Valencia, Diana, additional, Durante, Daniele, additional, Ida, Shigeru, additional, Bolton, Scott J, additional, Li, Cheng, additional, Stevenson, Kevin B., additional, Bean, Jacob, additional, Cowan, Nicolas B, additional, Hofstadter, Mark D., additional, Alonso, Ricardo Hueso, additional, Leconte, Jérémy, additional, Li, Liming, additional, Mordasini, Christoph, additional, Mousis, Olivier, additional, Nettelmann, Nadine, additional, Soderlund, Krista, additional, and Wong, Mike, additional

Published
2021
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174. Rotational modulations of a rare planetary-mass object at the end of the L/T transition

Author

Lew, Ben Wei Peng, Apai, Dániel, Zhou, Yifan, Radigan,Jacqueline, Marley, Mark, Schneider, Glenn, Cowan, Nicolas B., Miles-Páez, Paulo A., Manjavacas, Elena, Karalidi,Theodora, Bedin,L. R., Lowrance, Patrick J., and Burgasser, Adam J.

Subjects
Astrophysics::Earth and Planetary Astrophysics, planetary atmospheres, brown dwarfs
Abstract

Among the greatest challenges in understanding ultra-cool brown dwarf and exoplanet atmospheres is the evolution of cloud structure as a function of temperature and gravity. In the narrow effective temperature range across the L/T spectral-type transition, the drastic color (J-H, J-Ks) change across the L/T transition objects demonstrates the key role of cloud structure evolution for the near-infrared spectra of ultra-cool atmospheres. One of the most powerful methods to study the cloud structure is time-resolved spectrophotometry. Based on the rotation-modulated flux variation, we can constrain the rotational asymmetric features in a heterogeneous atmosphere. Understanding the atmospheric heterogeneity of L/T transition objects with different gravities and temperatures allows us to test different possible mechanisms to explain the L/T transition. In my talk, I will present the HST high-precision time-resolved spectra of a rare mid-T planetary-mass object at the end of the L/T transition. With this object, we now have collected a small sample of valuable low-gravity objects with detected rotation-modulated spectral modulation across the L/T transition. Based on the sample with detected spectral variability, I will also present a tentative trend across the L/T transition on the color-magnitude diagram.

Published
2019
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175. Astronomy in a Low-Carbon Future

Author

Matzner, Christopher, Cowan, Nicolas B., Doyon, Rene, Hénault-Brunet, Vincent, Lafrenière, David, Lokken, Martine, Martin, Peter G., Morsink, Sharon, Nomandeau, Magdalen, Ouellette, Nathalie, Rahman, Mubdi, Roediger, Joel, Taylor, James, Thacker, Rob, and van Kerkwijk, Marten

Subjects
astrophysics
Abstract

The consequences of climate change are developing into a vast and unparalleled crisis, which is planetary in scale and yet very human in its causes and impacts. Faced with this truth, inaction and delay are neither ethical nor wise: every field of human activity, astronomy included, must take urgent steps to mitigate the crisis and avoid the worst potential outcomes, while adapting to those that are inevitable. We outline a strategy for climate-responsible scholarship and communication that we hope will resonate with the astronomical community's aspirations for a stable future in which there is room for curiosity and discovery. In light of the crisis, greenhouse gas emissions must be understood as significant research costs to be justified, budgeted, and rationed. Air travel is a major contributor. We must remove incentives in tenure and promotions for profligate travel, codify low-carbon practices, and reward efforts to minimize emissions while maximizing research. Any essential travel emissions must be fully offset, with carbon offsets that are reimbursable if not covered by the institution. The frequency, timing, and locations of conferences and colloquia should be planned to minimize air travel, with remote participation encouraged using online platforms. Conferences should favour lowest-impact food options by default, taking steps to minimize food waste (and other waste as well). Infrastructure must be planned with climate impacts in mind for both construction and operation. For buildings, this means pushing for designs and materials at the forefront of sustainable technology. For observatories and computing facilities, it includes justifying and thoroughly vetting the emissions footprint at the proposal stage and fully considering low-impact options, such as cloud computing. In education and outreach, we must strive to be reliable sources of scientific information on climate change, prepared to connect this to astrophysics and ready to direct curious people to authoritative sources. We recommended that CASCA support this transformation by establishing a sustainability committee (or office) to be tasked with conducting a community-wide survey of our greenhouse gas emissions and developing a decarbonization road map for the discipline. This committee would host sustainability forums and provide resources to support each of our other recommendations, especially climate-related materials and references for education and outreach. We recommend that CASCA push for climate-responsible governance. Governments, granting agencies, and universities must implement climate-responsible policies, like rationing the carbon budget of the entire discipline, using climate impacts to evaluate proposals, permitting the use of funds for offsets, and allowing climate-friendly but more costly travel options. Moreover, these entities must ultimately ration emissions to ensure that targets are met. To have an impact beyond the bounds of professional astronomy, we encourage astronomers to press their institutions to divest from fossil fuel extraction and its financing. Finally, we recommend that climate responsibility be an explicit priority in the 2020 Long Range Plan, and that it be used to guide all aspects of our profession, from our research and education practices to our infrastructure., White paper identifier W021

Published
2019
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178. Phase Curves of Hot Neptune LTT 9779b Suggest a High-metallicity Atmosphere

Author

Crossfield, Ian J. M., primary, Dragomir, Diana, additional, Cowan, Nicolas B., additional, Daylan, Tansu, additional, Wong, Ian, additional, Kataria, Tiffany, additional, Deming, Drake, additional, Kreidberg, Laura, additional, Mikal-Evans, Thomas, additional, Gorjian, Varoujan, additional, Jenkins, James S., additional, Benneke, Björn, additional, Collins, Karen A., additional, Burke, Christopher J., additional, Henze, Christopher E., additional, McDermott, Scott, additional, Mireles, Ismael, additional, Watanabe, David, additional, Wohler, Bill, additional, Ricker, George, additional, Vanderspek, Roland, additional, Seager, Sara, additional, and Jenkins, Jon M., additional

Published
2020
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179. Atmospheric characterization of hot Jupiters using hierarchical models of Spitzer observations.

Author

Keating, Dylan and Cowan, Nicolas B

Subjects
*HOT Jupiters, *BRIGHTNESS temperature, *PLANETARY observations, *PLANETS
Abstract

The field of exoplanet atmospheric characterization is trending towards comparative studies involving many planetary systems, and using Bayesian hierarchical modelling is a natural next step. Here we demonstrate two use cases. We first use hierarchical modelling to quantify variability in repeated observations by reanalysing a suite of 10 Spitzer secondary eclipse observations of the hot Jupiter XO-3 b. We compare three models: one where we fit 10 separate eclipse depths, one where we use a single eclipse depth for all 10 observations, and a hierarchical model. By comparing the widely applicable information criterion of each model, we show that the hierarchical model is preferred over the others. The hierarchical model yields less scatter across the suite of eclipse depths – and higher precision on the individual eclipse depths – than does fitting the observations separately. We find that the hierarchical eclipse depth uncertainty is larger than the uncertainties on the individual eclipse depths, which suggests either slight astrophysical variability or that single eclipse observations underestimate the true eclipse depth uncertainty. Finally, we fit a suite of published dayside brightness measurements for 37 planets using a hierarchical model of brightness temperature versus irradiation temperature. The hierarchical model gives tighter constraints on the individual brightness temperatures than the non-hierarchical model. Although we tested hierarchical modelling on Spitzer eclipse data of hot Jupiters, it is applicable to observations of smaller planets like hot Neptunes and super-Earths, as well as for photometric and spectroscopic transit or phase-curve observations. [ABSTRACT FROM AUTHOR]

Published
2022
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181. Smaller than Expected Bright-spot Offsets in Spitzer Phase Curves of the Hot Jupiter Qatar-1b

Author

Keating, Dylan, primary, Stevenson, Kevin B., additional, Cowan, Nicolas B., additional, Rauscher, Emily, additional, Bean, Jacob L., additional, Bell, Taylor, additional, Dang, Lisa, additional, Deming, Drake, additional, Désert, Jean-Michel, additional, Feng, Y. Katherina, additional, Fortney, Jonathan J., additional, Kataria, Tiffany, additional, Kempton, Eliza M.-R., additional, Lewis, Nikole, additional, Line, Michael R., additional, Mansfield, Megan, additional, May, Erin, additional, Morley, Caroline, additional, and Showman, Adam P., additional

Published
2020
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182. Cloud Atlas: High-precision HST/WFC3/IR Time-resolved Observations of Directly Imaged Exoplanet HD 106906b

Author

Zhou, Yifan, primary, Apai, Dániel, additional, Bedin, Luigi R., additional, Lew, Ben W. P., additional, Schneider, Glenn, additional, Burgasser, Adam J., additional, Manjavacas, Elena, additional, Karalidi, Theodora, additional, Metchev, Stanimir, additional, Miles-Páez, Paulo A., additional, Cowan, Nicolas B., additional, Lowrance, Patrick J., additional, and Radigan, Jacqueline, additional

Published
2020
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183. Cloud Atlas: Weak Color Modulations Due to Rotation in the Planetary-mass Companion GU Psc b and 11 Other Brown Dwarfs

Author

Lew, Ben W. P., primary, Apai, Dániel, additional, Zhou, Yifan, additional, Radigan, Jacqueline, additional, Marley, Mark, additional, Schneider, Glenn, additional, Cowan, Nicolas B., additional, Miles-Páez, Paulo A., additional, Manjavacas, Elena, additional, Karalidi, Theodora, additional, Bedin, L. R., additional, Lowrance, Patrick J., additional, and Burgasser, Adam J., additional

Published
2020
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184. Evaluating Climate Variability of the Canonical Hot-Jupiters HD 189733b and HD 209458b through Multi-epoch Eclipse Observations

Author

Kilpatrick, Brian M., primary, Kataria, Tiffany, additional, Lewis, Nikole K., additional, Zellem, Robert T., additional, Henry, Gregory W., additional, Cowan, Nicolas B., additional, de Wit, Julien, additional, Fortney, Jonathan J., additional, Knutson, Heather, additional, Seager, Sara, additional, Showman, Adam P., additional, and Tucker, Gregory S., additional

Published
2020
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185. Evidence for H2 Dissociation and Recombination Heat Transport in the Atmosphere of KELT-9b

Author

Mansfield, Megan, primary, Bean, Jacob L., additional, Stevenson, Kevin B., additional, Komacek, Thaddeus D., additional, Bell, Taylor J., additional, Tan, Xianyu, additional, Malik, Matej, additional, Beatty, Thomas G., additional, Wong, Ian, additional, Cowan, Nicolas B., additional, Dang, Lisa, additional, Désert, Jean-Michel, additional, Fortney, Jonathan J., additional, Gaudi, B. Scott, additional, Keating, Dylan, additional, Kempton, Eliza M.-R., additional, Kreidberg, Laura, additional, Line, Michael R., additional, Parmentier, Vivien, additional, Stassun, Keivan G., additional, Swain, Mark R., additional, and Zellem, Robert T., additional

Published
2020
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187. Thermal Phase Variations of WASP-12b: Defying Predictions

Author

Cowan, Nicolas B, Machalek, Pavel, Croll, Bryce, Shekhtman, Louis M, Burrows, Adam, Deming, Drake, Greene, Tom, and Hora, Joseph L

Subjects
Astrophysics
Abstract

We report Warm Spitzer full-orbit phase observations of WASP-12b at 3.6 and 4.5 micrometers. This extremely inflated hot Jupiter is thought to be overflowing its Roche lobe, undergoing mass loss and accretion onto its host star, and has been claimed to have a C/O ratio in excess of unity. We are able to measure the transit depths, eclipse depths, thermal and ellipsoidal phase variations at both wavelengths. The large-amplitude phase variations, combined with the planet's previously measured dayside spectral energy distribution, are indicative of non-zero Bond albedo and very poor day-night heat redistribution. The transit depths in the mid-infrared-(R(sub p)/R(sub ∗))(sup 2) = 0.0123(3) and 0.0111(3) at 3.6 and 4.5 micrometers, respectively-indicate that the atmospheric opacity is greater at 3.6 than at 4.5 micrometers, in disagreement with model predictions, irrespective of C/O ratio. The secondary eclipse depths are consistent with previous studies: F(sub day)/F(sub ∗) = 0.0038(4) and 0.0039(3) at 3.6 and 4.5 micrometers, respectively. We do not detect ellipsoidal variations at 3.6 micrometers, but our parameter uncertainties-estimated via prayer-bead Monte Carlo-keep this non-detection consistent with model predictions. At 4.5 micrometers, on the other hand, we detect ellipsoidal variations that are much stronger than predicted. If interpreted as a geometric effect due to the planet's elongated shape, these variations imply a 3:2 ratio for the planet's longest:shortest axes and a relatively bright day-night terminator. If we instead presume that the 4.5 micrometer ellipsoidal variations are due to uncorrected systematic noise and we fix the amplitude of the variations to zero, the best-fit 4.5 micrometer transit depth becomes commensurate with the 3.6 micrometer depth, within the uncertainties. The relative transit depths are then consistent with a solar composition and short scale height at the terminator. Assuming zero ellipsoidal variations also yields a much deeper 4.5 micrometer eclipse depth, consistent with a solar composition and modest temperature inversion. We suggest future observations that could distinguish between these two scenarios.

Published
2012
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190. Mass loss from the exoplanet WASP-12b inferred from Spitzer phase curves

Author

Bell, Taylor J, primary, Zhang, Michael, additional, Cubillos, Patricio E, additional, Dang, Lisa, additional, Fossati, Luca, additional, Todorov, Kamen O, additional, Cowan, Nicolas B, additional, Deming, Drake, additional, Zellem, Robert T, additional, Stevenson, Kevin B, additional, Crossfield, Ian J M, additional, Dobbs-Dixon, Ian, additional, Fortney, Jonathan J, additional, Knutson, Heather A, additional, and Line, Michael R, additional

Published
2019
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191. Erratum: “Cloud Atlas: High-contrast Time-resolved Observations of Planetary-mass Companions” (2019, AJ, 157, 128)

Author

Zhou, Yifan, primary, Apai, Dániel, additional, Lew, Ben W. P., additional, Schneider, Glenn, additional, Manjavacas, Elena, additional, Bedin, Luigi R., additional, Cowan, Nicolas B., additional, Marley, Mark S., additional, Radigan, Jacqueline, additional, Karalidi, Theodora, additional, Lowrance, Patrick J., additional, Miles-Páez, Paulo A., additional, Metchev, Stanimir, additional, and Burgasser, Adam J., additional

Published
2019
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193. Cloud Atlas: High-contrast Time-resolved Observations of Planetary-mass Companions

Author

Zhou, Yifan, primary, Apai, Dániel, additional, Lew, Ben W. P., additional, Schneider, Glenn, additional, Manjavacas, Elena, additional, Bedin, Luigi R., additional, Cowan, Nicolas B., additional, Marley, Mark S., additional, Radigan, Jacqueline, additional, Karalidi, Theodora, additional, Lowrance, Patrick J., additional, Miles-Páez, Paulo A., additional, Metchev, Stanimir, additional, and Burgasser, Adam J., additional

Published
2019
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