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5 results on '"Mike Line"'

1. Atmospheric Retrieval of L Dwarfs: Benchmarking Results and Characterizing the Young Planetary Mass Companion HD 106906 b in the Near-infrared

Author

Arthur D. Adams, Michael R. Meyer, Alex R. Howe, Ben Burningham, Sebastian Daemgen, Jonathan Fortney, Mike Line, Mark Marley, Sascha P. Quanz, and Kamen Todorov

Subjects
Exoplanet astronomy, Extrasolar gaseous planets, Exoplanet atmospheres, Exoplanet atmospheric composition, Planetary atmospheres, Exoplanet structure, Astronomy, QB1-991
Abstract

We present model constraints on the atmospheric structure of HD 106906 b, a planetary-mass companion orbiting at a ∼700 au projected separation around a 15 Myr old stellar binary, using the APOLLO retrieval code on spectral data spanning 1.1–2.5 μ m. C/O ratios can provide evidence for companion formation pathways, as such pathways are ambiguous both at wide separations and at star-to-companion mass ratios in the overlap between the distributions of planets and brown dwarfs. We benchmark our code against an existing retrieval of the field L dwarf 2MASSW J2224–0158, returning a C/O ratio consistent with previous fits to the same JHK _s data, but disagreeing in the thermal structure, cloud properties, and atmospheric scale height. For HD 106906 b, we retrieve C/O $={0.53}_{-0.25}^{+0.15}$ , consistent with the C/O ratios expected for HD 106906's stellar association and therefore consistent with a stellar-like formation for the companion. We find abundances of H _2 O and CO near chemical equilibrium values for a solar metallicity but a surface gravity lower than expected, as well as a thermal profile with sharp transitions in the temperature gradient. Despite high signal-to-noise ratio and spectral resolution, more accurate constraints necessitate data across a broader wavelength range. This work serves as preparation for subsequent retrievals in the era of JWST, as JWST's spectral range provides a promising opportunity to resolve difficulties in fitting low-gravity L dwarfs and also underscores the need for simultaneous comparative retrievals on L-dwarf companions with multiple retrieval codes.

Published
2023
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2. The effect of stellar contamination on low-resolution transmission spectroscopy: needs identified by NASA’s Exoplanet Exploration Program Study Analysis Group 21

Author

Benjamin V Rackham, Néstor Espinoza, Svetlana V Berdyugina, Heidi Korhonen, Ryan J MacDonald, Benjamin T Montet, Brett M Morris, Mahmoudreza Oshagh, Alexander I Shapiro, Yvonne C Unruh, Elisa V Quintana, Robert T Zellem, Dániel Apai, Thomas Barclay, Joanna K Barstow, Giovanni Bruno, Ludmila Carone, Sarah L Casewell, Heather M Cegla, Serena Criscuoli, Catherine Fischer, Damien Fournier, Mark S Giampapa, Helen Giles, Aishwarya Iyer, Greg Kopp, Nadiia M Kostogryz, Natalie Krivova, Matthias Mallonn, Chima McGruder, Karan Molaverdikhani, Elisabeth R Newton, Mayukh Panja, Sarah Peacock, Kevin Reardon, Rachael M Roettenbacher, Gaetano Scandariato, Sami Solanki, Keivan G Stassun, Oskar Steiner, Kevin B Stevenson, Jeremy Tregloan-Reed, Adriana Valio, Sven Wedemeyer, Luis Welbanks, Jie Yu, Munazza K Alam, James R A Davenport, Drake Deming, Chuanfei Dong, Elsa Ducrot, Chloe Fisher, Emily Gilbert, Veselin Kostov, Mercedes López-Morales, Mike Line, Teo Močnik, Susan Mullally, Rishi R Paudel, Ignasi Ribas, and Jeff A Valenti

Published
2023
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3. The Effect of Stellar Contamination on Low-resolution Transmission Spectroscopy: Needs Identified by NASA's Exoplanet Exploration Program Study Analysis Group 21

Author

Benjamin V Rackham, Néstor Espinoza, Svetlana V Berdyugina, Heidi Korhonen, Ryan J MacDonald, Benjamin T Montet, Brett M Morris, Mahmoudreza Oshagh, Alexander I Shapiro, Yvonne C Unruh, Elisa V Quintana, Robert T Zellem, Dániel Apai, Thomas Barclay, Joanna K Barstow, Giovanni Bruno, Ludmila Carone, Sarah L Casewell, Heather M Cegla, Serena Criscuoli, Catherine Fischer, Damien Fournier, Mark S Giampapa, Helen Giles, Aishwarya Iyer, Greg Kopp, Nadiia M Kostogryz, Natalie Krivova, Matthias Mallonn, Chima McGruder, Karan Molaverdikhani, Elisabeth R Newton, Mayukh Panja, Sarah Peacock, Kevin Reardon, Rachael M Roettenbacher, Gaetano Scandariato, Sami Solanki, Keivan G Stassun, Oskar Steiner, Kevin B Stevenson, Jeremy Tregloan-Reed, Adriana Valio, Sven Wedemeyer, Luis Welbanks, Jie Yu, Munazza K Alam, James R A Davenport, Drake Deming, Chuanfei Dong, Elsa Ducrot, Chloe Fisher, Emily Gilbert, Veselin Kostov, Mercedes López-Morales, Mike Line, Teo Močnik, Susan Mullally, Rishi R Paudel, Ignasi Ribas, and Jeff A Valenti

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Astrophysics - Solar and Stellar Astrophysics, FOS: Physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

Study Analysis Group 21 (SAG21) of NASA's Exoplanet Exploration Program Analysis Group (ExoPAG) was organized to study the effect of stellar contamination on space-based transmission spectroscopy, a method for studying exoplanetary atmospheres by measuring the wavelength-dependent radius of a planet as it transits its star. Transmission spectroscopy relies on a precise understanding of the spectrum of the star being occulted. However, stars are not homogeneous, constant light sources but have temporally evolving photospheres and chromospheres with inhomogeneities like spots, faculae, plages, granules, and flares. This SAG brought together an interdisciplinary team of more than 100 scientists, with observers and theorists from the heliophysics, stellar astrophysics, planetary science, and exoplanetary atmosphere research communities, to study the current research needs that can be addressed in this context to make the most of transit studies from current NASA facilities like HST and JWST. The analysis produced 14 findings, which fall into three Science Themes encompassing (1) how the Sun is used as our best laboratory to calibrate our understanding of stellar heterogeneities ("The Sun as the Stellar Benchmark"), (2) how stars other than the Sun extend our knowledge of heterogeneities ("Surface Heterogeneities of Other Stars") and (3) how to incorporate information gathered for the Sun and other stars into transit studies ("Mapping Stellar Knowledge to Transit Studies"). In this invited review, we largely reproduce the final report of SAG21 as a contribution to the peer-reviewed literature., Invited review in press at RASTI. Based on the ExoPAG SAG21 report (arXiv:2201.09905v1) and refined via feedback from three reviewers. 75 pages, 30 figures, 5 tables

Published
2022

4. Astro2020 Science White Paper The Need for Laboratory Measurements and Ab Initio Studies to Aid Understanding of Exoplanetary Atmospheres

Author

Jonathan Fortney, Robinson, Tyler D., Shawn Domagal-Goldman, Del Genio, Anthony D., Gordon, Iouli E., Ehsan Gharib-Nezhad, Nikole Lewis, Clara Sousa-Silva, Vladimir Airapetian, Brian Drouin, Hargreaves, Robert J., Xinchuan Huang, Tijs Karman, Ramirez, Ramses M., Rieker, Gregory B., Jonathan Tennyson, Robin Wordsworth, Yurchenko, Sergei N., Johnson, Alexandria V., Lee, Timothy J., Chuanfei Dong, Stephen Kane, Mercedes Lopez-Morales, Thomas Fauchez, Timothy Lee, Marley, Mark S., Keeyoon Sung, Nader Haghighipour, Tyler Robinson, Sarah Horst, Peter Gao, Der-You Kao, Courtney Dressing, Roxana Lupu, Daniel Wolf Savin, Benjamin Fleury, Olivia Venot, Daniela Ascenzi, Stefanie Milam, Harold Linnartz, Murthy Gudipati, Guillaume Gronoff, Farid Salama, Lisseth Gavilan, Jordy Bouwman, Martin Turbet, Yves Benilan, Bryana Henderson, Natalie Batalha, Rebecca Jensen-Clem, Timothy Lyons, Richard Freedman, Edward Schwieterman, Jayesh Goyal, Luigi Mancini, Patrick Irwin, Jean-Michel Desert, Karan Molaverdikhani, John Gizis, Jake Taylor, Joshua Lothringer, Raymond Pierrehumbert, Robert Zellem, Natasha Batalha, Sarah Rugheimer, Jacob Lustig-Yaeger, Renyu Hu, Eliza Kempton, Giada Arney, Mike Line, Munazza Alam, Julianne Moses, Nicolas Iro, Laura Kreidberg, Jasmina Blecic, Tom Louden, Paul Molliere, Kevin Stevenson, Mark Swain, Kimberly Bott, Nikku Madhusudhan, Joshua Krissansen-Totton, Drake Deming, Irina Kitiashvili, Evgenya Shkolnik, Zafar Rustamkulov, Leslie Rogers, Laird Close, and Venot, Olivia

Subjects
[SDU.ASTR] Sciences of the Universe [physics]/Astrophysics [astro-ph]

5. SPITZER OBSERVATIONS OF EXOPLANETS DISCOVERED WITH THE KEPLER K2 MISSION.

Author

Charles Beichman, John Livingston, Michael Werner, Varoujan Gorjian, Jessica Krick, Katherine Deck, Heather Knutson, Ian Wong, Erik Petigura, Jessie Christiansen, David Ciardi, Thomas P. Greene, Joshua E. Schlieder, Mike Line, Ian Crossfield, Andrew Howard, and Evan Sinukoff

Subjects
EXTRASOLAR planets, METAPHYSICS, CIRCUMSTELLAR matter, CONSTELLATIONS, PLANETARY systems
Abstract

We have used the Spitzer Space Telescope to observe two transiting planetary systems orbiting low-mass stars discovered in the Kepler K2 mission. The system K2-3 (EPIC 201367065) hosts three planets, while K2-26 (EPIC 202083828) hosts a single planet. Observations of all four objects in these two systems confirm and refine the orbital and physical parameters of the planets. The refined orbital information and more precise planet radii possible with Spitzer will be critical for future observations of these and other K2 targets. For K2-3b we find marginally significant evidence for a transit timing variation between the K2 and Spitzer epochs. [ABSTRACT FROM AUTHOR]

Published
2016
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