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TESS Hunt for Young and Maturing Exoplanets (THYME). VII. Membership, Rotation, and Lithium in the Young Cluster Group-X and a New Young Exoplanet

Newton, Elisabeth R. and Rampalli, Rayna and Kraus, Adam L. and Mann, Andrew W. and Curtis, Jason L. and Vanderburg, Andrew and Krolikowski, Daniel M. and Huber, Daniel and Petter, Grayson C. and Bieryla, Allyson and Tofflemire, Benjamin M. and Thao, Pa Chia and Wood, Mackenna L. and Kerr, Ronan and Safanov, Boris S. and Strakhov, Ivan A. and Ciardi, David R. and Giacalone, Steven and Dressing, Courtney D. and Gill, Holden and Savel, Arjun B. and Collins, Karen A. and Brown, Peyton and Murgas, Felipe and Isogai, Keisuke and Narita, Norio and Palle, Enric and Quinn, Samuel N. and Eastman, Jason D. and Furész, Gábor and Shiao, Bernie and Daylan, Tansu and Caldwell, Douglas A. and Ricker, George R. and Vanderspek, Roland K. and Seager, Sara and Winn, Joshua N. and Jenkins, Jon M. and Latham, David W. (2022) TESS Hunt for Young and Maturing Exoplanets (THYME). VII. Membership, Rotation, and Lithium in the Young Cluster Group-X and a New Young Exoplanet. Astronomical Journal, 164 (3). Art. No. 115. ISSN 0004-6256. doi:10.3847/1538-3881/ac8154.

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The public, all-sky surveys Gaia and TESS provide the ability to identify new young associations and determine their ages. These associations enable study of planetary evolution by providing new opportunities to discover young exoplanets. A young association was recently identified by Tang et al. and Fürnkranz et al. using astrometry from Gaia (called “Group-X” by the former). In this work, we investigate the age and membership of this association, and we validate the exoplanet TOI 2048 b, which was identified to transit a young, late G dwarf in Group-X using photometry from TESS. We first identified new candidate members of Group-X using Gaia EDR3 data. To infer the age of the association, we measured rotation periods for candidate members using TESS data. The clear color–period sequence indicates that the association is the same age as the 300 ± 50 Myr old NGC 3532. We obtained optical spectra for candidate members that show lithium absorption consistent with this young age. Further, we serendipitously identify a new, small association nearby Group-X, which we call MELANGE-2. Lastly, we statistically validate TOI 2048 b, which is a 2.1 ± 0.2 R ⊕ radius planet on a 13.8-day orbit around its 300 Myr old host star.

Item Type:Article
Related URLs:
URLURL TypeDescription
Newton, Elisabeth R.0000-0003-4150-841X
Rampalli, Rayna0000-0001-7337-5936
Kraus, Adam L.0000-0001-9811-568X
Mann, Andrew W.0000-0003-3654-1602
Curtis, Jason L.0000-0002-2792-134X
Vanderburg, Andrew0000-0001-7246-5438
Krolikowski, Daniel M.0000-0001-9626-0613
Huber, Daniel0000-0001-8832-4488
Petter, Grayson C.0000-0001-6941-8411
Bieryla, Allyson0000-0001-6637-5401
Tofflemire, Benjamin M.0000-0003-2053-0749
Thao, Pa Chia0000-0001-5729-6576
Wood, Mackenna L.0000-0001-7336-7725
Kerr, Ronan0000-0002-6549-9792
Safanov, Boris S.0000-0003-1713-3208
Strakhov, Ivan A.0000-0003-0647-6133
Ciardi, David R.0000-0002-5741-3047
Giacalone, Steven0000-0002-8965-3969
Dressing, Courtney D.0000-0001-8189-0233
Gill, Holden0000-0001-6171-7951
Savel, Arjun B.0000-0002-2454-768X
Collins, Karen A.0000-0001-6588-9574
Brown, Peyton0000-0002-3481-9052
Murgas, Felipe0000-0001-9087-1245
Isogai, Keisuke0000-0002-6480-3799
Narita, Norio0000-0001-8511-2981
Palle, Enric0000-0003-0987-1593
Quinn, Samuel N.0000-0002-8964-8377
Eastman, Jason D.0000-0003-3773-5142
Daylan, Tansu0000-0002-6939-9211
Caldwell, Douglas A.0000-0003-1963-9616
Ricker, George R.0000-0003-2058-6662
Vanderspek, Roland K.0000-0001-6763-6562
Seager, Sara0000-0002-6892-6948
Winn, Joshua N.0000-0002-4265-047X
Jenkins, Jon M.0000-0002-4715-9460
Latham, David W.0000-0001-9911-7388
Additional Information:E.R.N. and R.R. acknowledge support from the TESS Guest Investigator proposal G03141. A.W.M. was supported through a grant from NASA's Exoplanet Research Program (XRP), 80NSSC21K0393. C.D.D. was supported by NASA XRP grant 80NSSC20K0250. D.H. acknowledges support from the Alfred P. Sloan Foundation and the National Aeronautics and Space Administration (80NSSC21K0784). B.S.S. and I.A.S. acknowledge the support of Ministry of Science and Higher Education of the Russian Federation under the grant 075-15-2020-780 (N13.1902.21.0039). This research has made use of public auxiliary data provided by ESA/Gaia/DPAC/CU5 and prepared by Carine Babusiaux. This work has made use of data from the European Space Agency (ESA) mission Gaia (, processed by the Gaia Data Processing and Analysis Consortium (DPAC, Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This work is partly supported by JSPS KAKENHI grant No. JP18H05439 and JST CREST grant No. JPMJCR1761. This article is based on observations made with the MuSCAT2 instrument, developed by ABC, at Telescopio Carlos Sánchez, operated on the island of Tenerife by the IAC in the Spanish Observatorio del Teide. Funding for the TESS mission is provided by NASA's Science Mission Directorate. We acknowledge the use of public TESS data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. This research has made use of the Exoplanet Follow-up Observation Program website, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Alfred P. Sloan FoundationUNSPECIFIED
Ministry of Science and Higher Education (Russia)075-15-2020-780
Gaia Multilateral AgreementUNSPECIFIED
Japan Society for the Promotion of Science (JSPS)JP18H05439
Japan Science and Technology AgencyJPMJCR1761
Issue or Number:3
Record Number:CaltechAUTHORS:20220909-232865000
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:116881
Deposited By: Olivia Warschaw
Deposited On:29 Oct 2022 22:13
Last Modified:01 Nov 2022 18:09

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