OrCAS: Origins, Compositions, and Atmospheres of Sub-neptunes. I. Survey Definition

Sub-Neptunes – volatile-rich exoplanets smaller than Neptune – are intrinsically the most common type of planet known.

However, the formation and nature of these objects, as well as the distinctions between sub-classes (if any), remain unclear. Two powerful tools to tease out the secrets of these worlds are measurements of (i) atmospheric composition and structure revealed by transit and/or eclipse spectroscopy, and (ii) mass, radius, and density revealed by transit photometry and Doppler spectroscopy. Here we present OrCAS, a survey to better elucidate the origins, compositions, and atmospheres of sub-Neptunes.

This radial velocity survey uses a repeatable, quantifiable metric to select targets suitable for subsequent transmission spectroscopy and address key science themes about the atmospheric & internal compositions and architectures of these systems. Our survey targets 26 systems with transiting sub-Neptune planet candidates, with the overarching goal of increasing the sample of such planets suitable for subsequent atmospheric characterization.

This paper lays out our survey’s science goals, defines our target prioritization metric, and performs light-curve fits and statistical validation using existing TESS photometry and ground-based follow-up observations.

Our survey serves to continue expanding the sample of small exoplanets with well-measured properties orbiting nearby bright stars, ensuring fruitful studies of these systems for many years to come.

Ian J. M. Crossfield, Alex S. Polanski, Paul Robertson, Joseph Akana Murphy, Emma V. Turtelboom, Rafael Luque, Thomas Beatty, Tansu Daylan, Howard Isaacson, Jonathan Brande, Laura Kreidberg, Natalie M. Batalha, Daniel Huber, Maleah Rhem, Courtney Dressing, Stephen R. Kane, Malik Bossett, Anna Gagnebin, Maxwell A. Kroft, Pranav H. Premnath, Claire J. Rogers, Karen A. Collins, David W. Latham, Cristilyn N. Watkins, David R. Ciardi, Steve B. Howell, Arjun B. Savel, Perry Berlind, Michael L. Calkins, Gilbert A. Esquerdo, Jessica Mink, Catherine A. Clark, Michael B. Lund, Rachel A. Matson, Mark E. Everett, Joshua E. Schlieder, Elisabeth C. Matthews, Steven Giacalone, Thomas Barclay, Roberto Zambelli, Peter Plavchan, Taylor Ellingson, Michael Bowen, Gregor Srdoc, Kim K. McLeod, Richard P. Schwarz, Khalid Barkaoui, Jacob Kamler, Felipe Murgas, Enric Palle, Norio Narita, Akihiko Fukui, Howard M. Relles, Allyson Bieryla, Eric Girardin, Bob Massey, Chris Stockdale, Pablo Lewin, Riccardo Papini, Pere Guerra, Dennis M. Conti, Selcuk Yalcinkaya, Ozgur Basturk, Ghachoui Mourad

Comments: 20 pages, 4 figures, 4 tables, 26 sub-Neptunes, 31 TOIs. Accepted to AJ
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2411.16836 [astro-ph.EP] (or arXiv:2411.16836v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2411.16836
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Submission history
From: Ian Crossfield
[v1] Mon, 25 Nov 2024 19:00:01 UTC (345 KB)
https://arxiv.org/abs/2411.16836
Astrobiology,