J/AJ/166/181 HARPS-N and NEID radial velocities of TOI-1420 (Yoshida+, 2023)
TESS Spots a Super-puff: The Remarkably Low Density of TOI-1420b.
Yoshida S., Vissapragada S., Latham D.W., Bieryla A., Thorngren D.P.,
Eastman J.D., Lopez-Morales M., Barkaoui K., Beichman C., Berlind P.,
Buchave L.A., Calkins M.L., Ciardi D.R., Collins K.A., Cosentino R.,
Crossfield I.J.M., Dai F., DiTomasso V., Dowling N., Esquerdo G.A.,
Fores-Toribio R., Ghedina A., Goliguzova M.V., Golub E., Gonzales E.J.,
Horta F.G., Higuera J., Hoch N., Horne K., Howell S.B., Jenkins J.M.,
Klusmeyer J., Laloum D., Lissauer J.J., Logsdon S.E., Malavolta L.,
Matson R.A., Matthews E.C., McLeod K.K., Medina J.V., Munoz J.A.,
Osborn H.P., Safonov B., Schlieder J., Schmidt M., Schweiker H.,
Seager S., Sozzetti A., Srdoc G., Stefansson G., Strakhov I.A.,
Striegel S., Villasenor J., Winn J.N.
<Astron. J., 166, 181 (2023)>
=2023AJ....166..181Y 2023AJ....166..181Y
ADC_Keywords: Exoplanets; Stars, G-type; Spectra, optical; Radial velocities
Keywords: Exoplanets ; Transits ; Exoplanet structure
Abstract:
We present the discovery of TOI-1420b, an exceptionally low-density
(ρ=0.08±0.02g/cm3) transiting planet in a P=6.96days orbit
around a late G-dwarf star. Using transit observations from TESS,
LCOGT, Observatoire Prive du Mont, Whitin, Wendelstein, OAUV, Ca l'Ou,
and KeplerCam, along with radial velocity observations from HARPS-N
and NEID, we find that the planet has a radius of
Rp=11.9±0.3R⊕ and a mass of Mp=25.1±3.8M⊕.
TOI-1420b is the largest known planet with a mass less than
50M⊕, indicating that it contains a sizeable envelope of
hydrogen and helium. We determine TOI-1420b's envelope mass fraction
to be f~=82-6+7% , suggesting that runaway gas accretion occurred
when its core was at most four to five times the mass of the Earth.
TOI-1420b is similar to the planet WASP-107b in mass, radius, density,
and orbital period, so a comparison of these two systems may help
reveal the origins of close-in low-density planets. With an
atmospheric scale height of 1950km, a transmission spectroscopy metric
of 580, and a predicted Rossiter-McLaughlin amplitude of about 17m/s,
TOI-1420b is an excellent target for future atmospheric and dynamical
characterization.
Description:
The High Accuracy Radial velocity Planet Searcher for the Northern
hemisphere (HARPS-N) at the 3.6m Telescopio Nazionale Galileo (TNG)
in La Palma, Spain was used for radial velocities (RVel) observations.
HARPS-N is a highly stabilized echelle spectrograph with a resolving
power of R∼115000, capable of measuring RVel in the m/s regime. We
observed TOI-1420 between 2021 October 25 and 2022 September.
We also obtained RVel measurements with the NN-explore Exoplanet
Investigations with Doppler (NEID) spectroscopy instrument, a
high-resolution (R∼110,000) spectrograph at the WIYN 3.5m telescope on
Kitt Peak, Arizona. We obtained 990s exposures with the
high-resolution fiber between 2022 April 2 and 2022 June 6.
Objects:
------------------------------------------------------------------------
RA (2000) DE Designation(s) (Period)
------------------------------------------------------------------------
21 31 45.91 +66 20 55.9 TOI-1420 = 2MASS J21314590+6620556 (P=6.96d)
------------------------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 38 53 TOI-1420 radial velocity measurements from HARPS-N
and NEID
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See also:
I/259 : The Tycho-2 Catalogue (Hog+ 2000)
J/ApJ/757/18 : Radial velocities 16 hot Jupiter host stars (Albrecht+, 2012)
J/other/Nat/486.375 : Stellar parameters of KOI stars (Buchhave+, 2012)
J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 2014)
J/ApJ/831/64 : Mass-metallicity relation for giant planets (Thorngren+, 2016)
J/A+A/599/A3 : WASP 127, 136 and 138 RV and light curves (Lam+, 2017)
J/AJ/153/215 : Photometry and spectroscopy of KELT-11 (Pepper+, 2017)
J/AJ/153/142 : Radial velocities systems hosting sub-Saturns (Petigura+, 2017)
J/AJ/155/89 : California-Kepler Survey (CKS). IV. Planets (Petigura+, 2018)
J/AJ/156/102 : TESS Input Catalog and Candidate Target List (Stassun+, 2018)
J/ApJ/874/L31 : Giant planet bulk & atmosphere metallicities (Thorngren+, 2019)
J/ApJS/254/39 : Exoplanet candidates from TESS first 2yr obs (Guerrero+, 2021)
J/AJ/161/70 : RVvel for WASP-107 with HIRES & CORALIE (Piaulet+, 2021)
J/AJ/161/119 : The TESS-Keck survey. IV. Rvel for WASP-107 (Rubenzahl+, 2021)
J/ApJS/258/16 : TESS Eclipsing Binary stars. I. Sectors 1-26 (Prsa+, 2022)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Inst Instrument identifier
9- 23 F15.7 d BJD [2459513/2459829] Barycentric Julian Date; TDB
25- 33 F9.2 m/s RVel [-10354/-10228] Radial velocity
35- 38 F4.2 m/s e_RVel [1/8] Uncertainty in RVel
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 09-Apr-2024