TY - JOUR
T1 - Assessing the C/O Ratio Formation Diagnostic
T2 - A Potential Trend with Companion Mass
AU - Hoch, Kielan K.W.
AU - Konopacky, Quinn M.
AU - Theissen, Christopher A.
AU - Ruffio, Jean Baptiste
AU - Barman, Travis S.
AU - Rickman, Emily L.
AU - Perrin, Marshall D.
AU - Macintosh, Bruce
AU - Marois, Christian
N1 - Funding Information:
The authors thank the anonymous referee for aiding in the publication of this work. The authors would like to thank Randy Campbell, Heather Hershley, and Tony Connors for their support in obtaining these observations. K.K.W.H., Q.M.K, and T.S.B acknowledge support by the National Aeronautics and Space Administration under Grants/Contracts/Agreements No. NNX17AB63G and 80NSSC21K0573 issued through the Astrophysics Division of the Science Mission Directorate. T.S.B. acknowledges support by the National Science Foundation under grant No. 1614492. Any opinions, findings, conclusions, and/or recommendations expressed in this paper are those of the author(s) and do not reflect the views of the National Aeronautics and Space Administration. The data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The W.M. Keck Observatory was made possible by the financial support of the W.M. Keck Foundation. The authors wish to acknowledge the significant cultural role that the summit of Maunakea has always had within the indigenous Hawaiian community. The author(s) are extremely fortunate to conduct observations from this mountain. Portions of this work were conducted at the University of California, San Diego, which was built on the unceded territory of the Kumeyaay Nation, whose people continue to maintain their political sovereignty and cultural traditions as vital members of the San Diego community.The facility [Keck/OSIRIS] does not appear in the approved list of facilities. For the list of available facilities, please see the website https://journals.aas.org/facility-keywords/.
Funding Information:
The authors thank the anonymous referee for aiding in the publication of this work. The authors would like to thank Randy Campbell, Heather Hershley, and Tony Connors for their support in obtaining these observations. K.K.W.H., Q.M.K, and T.S.B acknowledge support by the National Aeronautics and Space Administration under Grants/Contracts/Agreements No. NNX17AB63G and 80NSSC21K0573 issued through the Astrophysics Division of the Science Mission Directorate. T.S.B. acknowledges support by the National Science Foundation under grant No. 1614492. Any opinions, findings, conclusions, and/or recommendations expressed in this paper are those of the author(s) and do not reflect the views of the National Aeronautics and Space Administration. The data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The W.M. Keck Observatory was made possible by the financial support of the W.M. Keck Foundation. The authors wish to acknowledge the significant cultural role that the summit of Maunakea has always had within the indigenous Hawaiian community. The author(s) are extremely fortunate to conduct observations from this mountain. Portions of this work were conducted at the University of California, San Diego, which was built on the unceded territory of the Kumeyaay Nation, whose people continue to maintain their political sovereignty and cultural traditions as vital members of the San Diego community.The facility [Keck/OSIRIS] does not appear in the approved list of facilities. For the list of available facilities, please see the website https://journals.aas.org/facility-keywords/ .
Publisher Copyright:
© 2023. The Author(s). Published by the American Astronomical Society.
PY - 2023/9/1
Y1 - 2023/9/1
N2 - The carbon-to-oxygen (C/O) ratio in an exoplanet atmosphere has been suggested as a potential diagnostic of planet formation. Now that a number of exoplanets have measured C/O ratios, it is possible to examine this diagnostic at a population level. Here, we present an analysis of currently measured C/O ratios of directly imaged and transit/eclipse planets. First, we derive atmospheric parameters for the substellar companion HD 284149 AB b using data taken with the OSIRIS integral field spectrograph at the W.M. Keck Observatory and report two non-detections from our ongoing imaging spectroscopy survey with Keck/OSIRIS. We find an effective temperature of T eff = 2502 K, with a range of 2291-2624 K, log g = 4.52 , with a range of 4.38-4.91, and [M/H] = 0.37, with a range of 0.10-0.55. We derive a C/O of 0.59 − 0.30 + 0.15 for HD 284149 AB b. We add this measurement to the list of C/O ratios for directly imaged planets and compare them with those from a sample of transit/eclipse planets. We also derive the first dynamical mass estimate for HD 284149 AB b, finding a mass of ∼28 M Jup. There is a trend in C/O ratio with companion mass (M Jup), with a break seen around 4 M Jup. We run a Kolmogorov-Smirnov and an Anderson-Darling test on planets above and below this mass boundary, and find that they are two distinct populations. This could be additional evidence of two distinct populations possibly having two different formation pathways, with companion mass as an indicator of most likely formation scenario.
AB - The carbon-to-oxygen (C/O) ratio in an exoplanet atmosphere has been suggested as a potential diagnostic of planet formation. Now that a number of exoplanets have measured C/O ratios, it is possible to examine this diagnostic at a population level. Here, we present an analysis of currently measured C/O ratios of directly imaged and transit/eclipse planets. First, we derive atmospheric parameters for the substellar companion HD 284149 AB b using data taken with the OSIRIS integral field spectrograph at the W.M. Keck Observatory and report two non-detections from our ongoing imaging spectroscopy survey with Keck/OSIRIS. We find an effective temperature of T eff = 2502 K, with a range of 2291-2624 K, log g = 4.52 , with a range of 4.38-4.91, and [M/H] = 0.37, with a range of 0.10-0.55. We derive a C/O of 0.59 − 0.30 + 0.15 for HD 284149 AB b. We add this measurement to the list of C/O ratios for directly imaged planets and compare them with those from a sample of transit/eclipse planets. We also derive the first dynamical mass estimate for HD 284149 AB b, finding a mass of ∼28 M Jup. There is a trend in C/O ratio with companion mass (M Jup), with a break seen around 4 M Jup. We run a Kolmogorov-Smirnov and an Anderson-Darling test on planets above and below this mass boundary, and find that they are two distinct populations. This could be additional evidence of two distinct populations possibly having two different formation pathways, with companion mass as an indicator of most likely formation scenario.
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U2 - 10.3847/1538-3881/ace442
DO - 10.3847/1538-3881/ace442
M3 - Article
AN - SCOPUS:85167651563
SN - 0004-6256
VL - 166
JO - Astronomical Journal
JF - Astronomical Journal
IS - 3
M1 - 85
ER -