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TKS X: Confirmation of TOI-1444b and a Comparative Analysis of the Ultra-short-period Planets with Hot Neptunes

Dai, Fei and Howard, Andrew W. and Batalha, Natalie M. and Beard, Corey and Behmard, Aida and Blunt, Sarah and Brinkman, Casey L. and Chontos, Ashley and Crossfield, Ian J. M. and Dalba, Paul A. and Dressing, Courtney and Fulton, Benjamin and Giacalone, Steven and Hill, Michelle L. and Huber, Daniel and Isaacson, Howard and Kane, Stephen R. and Lubin, Jack and Mayo, Andrew and Močnik, Teo and Akana Murphy, Joseph M. and Petigura, Erik A. and Rice, Malena and Robertson, Paul and Rosenthal, Lee and Roy, Arpita and Rubenzahl, Ryan A. and Weiss, Lauren M. and Zandt, Judah Van and Beichman, Charles and Ciardi, David and Collins, Karen A. and Gonzales, Erica and Howell, Steve B. and Matson, Rachel A. and Matthews, Elisabeth C. and Schlieder, Joshua E. and Schwarz, Richard P. and Ricker, George R. and Vanderspek, Roland and Latham, David W. and Seager, Sara and Winn, Joshua N. and Jenkins, Jon M. and Caldwell, Douglas A. and Colon, Knicole D. and Dragomir, Diana and Lund, Michael B. and McLean, Brian and Rudat, Alexander and Shporer, Avi (2021) TKS X: Confirmation of TOI-1444b and a Comparative Analysis of the Ultra-short-period Planets with Hot Neptunes. Astronomical Journal, 162 (2). Art. No. 62. ISSN 0004-6256. doi:10.3847/1538-3881/ac02bd.

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We report the discovery of TOI-1444b, a 1.4 R_⊕ super-Earth on a 0.47 day orbit around a Sun-like star discovered by TESS. Precise radial velocities from Keck/HIRES confirmed the planet and constrained the mass to be 3.87 ± 0.71M_⊕. The RV data set also indicates a possible nontransiting, 16 day planet (11.8 ± 2.9M_⊕). We report a tentative detection of phase-curve variation and a secondary eclipse of TOI-1444b in the TESS bandpass. TOI-1444b joins the growing sample of 17 ultra-short-period planets (USPs) with well-measured masses and sizes, most of which are compatible with an Earth-like composition. We take this opportunity to examine the expanding sample of ultra-short-period planets (<2R_⊕) and contrast them with the newly discovered sub-day ultrahot Neptunes (>3R_⊕, >2000F_⊕ TOI-849 b, LTT9779 b, and K2-100). We find that (1) USPs have predominately Earth-like compositions with inferred iron core mass fractions of 0.32 ± 0.04 and have masses below the threshold of runaway accretion (~10M_⊕), while ultrahot Neptunes are above the threshold and have H/He or other volatile envelopes. (2) USPs are almost always found in multi-planet systems consistent with a secular interaction formation scenario; ultrahot Neptunes (P_(orb) ≾1 day) tend to be "lonely," similar to longer-period hot Neptunes (P_(orb) 1–10 days) and hot Jupiters. (3) USPs occur around solar-metallicity stars while hot Neptunes prefer higher metallicity hosts. (4) In all these respects, ultrahot Neptunes show more resemblance to hot Jupiters than the smaller USP planets, although ultrahot Neptunes are rarer than both USPs and hot Jupiters by 1–2 orders of magnitude.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Dai, Fei0000-0002-8958-0683
Howard, Andrew W.0000-0001-8638-0320
Batalha, Natalie M.0000-0002-7030-9519
Beard, Corey0000-0001-7708-2364
Behmard, Aida0000-0003-0012-9093
Blunt, Sarah0000-0002-3199-2888
Brinkman, Casey L.0000-0002-4480-310X
Chontos, Ashley0000-0003-1125-2564
Crossfield, Ian J. M.0000-0002-1835-1891
Dalba, Paul A.0000-0002-4297-5506
Dressing, Courtney0000-0001-8189-0233
Fulton, Benjamin0000-0003-3504-5316
Giacalone, Steven0000-0002-8965-3969
Hill, Michelle L.0000-0002-0139-4756
Huber, Daniel0000-0001-8832-4488
Isaacson, Howard0000-0002-0531-1073
Kane, Stephen R.0000-0002-7084-0529
Lubin, Jack0000-0001-8342-7736
Mayo, Andrew0000-0002-7216-2135
Močnik, Teo0000-0003-4603-556X
Akana Murphy, Joseph M.0000-0001-8898-8284
Petigura, Erik A.0000-0003-0967-2893
Rice, Malena0000-0002-7670-670X
Robertson, Paul0000-0003-0149-9678
Rosenthal, Lee0000-0001-8391-5182
Roy, Arpita0000-0001-8127-5775
Rubenzahl, Ryan A.0000-0003-3856-3143
Weiss, Lauren M.0000-0002-3725-3058
Zandt, Judah Van0000-0002-4290-6826
Beichman, Charles0000-0002-5627-5471
Ciardi, David0000-0002-5741-3047
Collins, Karen A.0000-0001-6588-9574
Gonzales, Erica0000-0002-9329-2190
Howell, Steve B.0000-0002-2532-2853
Matson, Rachel A.0000-0001-7233-7508
Matthews, Elisabeth C.0000-0003-0593-1560
Schlieder, Joshua E.0000-0001-5347-7062
Schwarz, Richard P.0000-0001-8227-1020
Ricker, George R.0000-0003-2058-6662
Vanderspek, Roland0000-0001-6763-6562
Latham, David W.0000-0001-9911-7388
Seager, Sara0000-0002-6892-6948
Winn, Joshua N.0000-0002-4265-047X
Jenkins, Jon M.0000-0002-4715-9460
Caldwell, Douglas A.0000-0003-1963-9616
Colon, Knicole D.0000-0001-8020-7121
Dragomir, Diana0000-0003-2313-467X
Lund, Michael B.0000-0003-2527-1598
McLean, Brian0000-0002-8058-643X
Shporer, Avi0000-0002-1836-3120
Additional Information:© 2021. The American Astronomical Society. Received 2021 April 12; revised 2021 May 13; accepted 2021 May 17; published 2021 July 16. We thank Heather Knutson, Yayaati Chachan, and Shreyas Vissapragada for insightful discussions. We thank the time assignment committees of the University of California, the California Institute of Technology, NASA, and the University of Hawaii for supporting the TESS-Keck Survey with observing time at Keck Observatory and on the Automated Planet Finder. We thank NASA for funding associated with our Key Strategic Mission Support project. We gratefully acknowledge the efforts and dedication of the Keck Observatory staff for support of HIRES and remote observing. We recognize and acknowledge the cultural role and reverence that the summit of Maunakea has within the indigenous Hawaiian community. We are deeply grateful to have the opportunity to conduct observations from this mountain. We thank Ken and Gloria Levy, who supported the construction of the Levy Spectrometer on the Automated Planet Finder. We thank the University of California and Google for supporting Lick Observatory and the UCO staff for their dedicated work scheduling and operating the telescopes of Lick Observatory. This paper is based on data collected by the TESS mission. Funding for the TESS mission is provided by the NASA Explorer Program. This work makes use of observations from the LCOGT network. LCOGT telescope time was granted by NOIRLab through the Mid-Scale Innovations Program (MSIP). MSIP is funded by NSF. Part of this work has been carried out within the framework of the National Centre of Competence in Research Planets supported by the Swiss National Science Foundation. E.C.M. acknowledges financial support from the SNSF. Based on observations obtained at the international Gemini Observatory, a program of NSF's NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation on behalf of the Gemini Observatory partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). J.M.A.M. is supported by the National Science Foundation Graduate Research Fellowship Program under grant No. DGE-1842400. J.M.A.M. acknowledges the LSSTC Data Science Fellowship Program, which is funded by LSSTC, NSF Cybertraining grant No. 1829740, the Brinson Foundation, and the Moore Foundation; his participation in the program has benefited this work. D.H. acknowledges support from the Alfred P. Sloan Foundation, the National Aeronautics and Space Administration (80NSSC19K0379), and the National Science Foundation (AST-1717000). 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. We acknowledge the use of public TESS Alert data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. J.N.W. thanks the Heising-Simons foundation for support. D.D. acknowledges support from the TESS Guest Investigator Program grant 80NSSC19K1727 and NASA Exoplanet Research Program grant 18-2XRP18_2-0136. L.M.W. is supported by the Beatrice Watson Parrent Fellowship and NASA ADAP grant 80NSSC19K0597. Software: AstroImage (Collins et al. 2017), Isoclassify (Huber et al. 2017), MIST (Choi et al. 2016), SpecMatch-Syn (Petigura 2015), Batman (Kreidberg 2015), emcee (Foreman-Mackey et al. 2013), RVSearch, RadVel (Fulton et al. 2018).
Group:Astronomy Department, Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Swiss National Science Foundation (SNSF)UNSPECIFIED
NSF Graduate Research FellowshipDGE-1842400
Large Synoptic Survey Telescope CorporationUNSPECIFIED
Brinson FoundationUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Heising-Simons FoundationUNSPECIFIED
Beatrice Watson Parrent FellowshipUNSPECIFIED
Subject Keywords:Exoplanets; Super Earths; Extrasolar rocky planets
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Exoplanets (498); Super Earths (1655); Extrasolar rocky planets (511)
Record Number:CaltechAUTHORS:20210727-213650344
Persistent URL:
Official Citation:Fei Dai et al 2021 AJ 162 62
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:110044
Deposited By: Tony Diaz
Deposited On:02 Aug 2021 20:25
Last Modified:02 Aug 2021 20:25

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