J/AJ/162/79 HARPS radial velocity follow up of TOI-1634 (Cloutier+, 2021)
TOI-1634 b: an ultra-short-period keystone planet sitting inside the M-dwarf
radius valley.
Cloutier R., Charbonneau D., Stassun K.G., Murgas F., Mortier A.,
Massey R., Lissauer J.J., Latham D.W., Irwin J., Haywood R.D., Guerra P.,
Girardin E., Giacalone S.A., Bosch-cabot P., Bieryla A., Winn J.,
Watson C.A., Vanderspek R., Udry S., Tamura M., Sozzetti A., Shporer A.,
Segransan D., Seager S., Savel A.B., Sasselov D., Rose M., Ricker G.,
Rice K., Quintana E.V., Quinn S.N., Piotto G., Phillips D., Pepe F.,
Pedani M., Parviainen H., Palle E., Narita N., Molinari E., Micela G.,
Mcdermott S., Mayor M., Matson R.A., Martinez Fiorenzano A.F., Lovis C.,
Lopez-morales M., Kusakabe N., Jensen E.L.N., Jenkins J.M., Huang C.X.,
Howell S.B., Harutyunyan A., Furesz G., Fukui A., Esquerdo G.A.,
Esparza-borges E., Dumusque X., Dressing C.D., Di Fabrizio L.,
Collins K.A., Cameron A.C., Christiansen J.L., Cecconi M., Buchhave L.A.,
Boschin W., Andreuzzi G.
<Astron. J., 162, 79-79 (2021)>
=2021AJ....162...79C 2021AJ....162...79C (SIMBAD/NED BibCode)
ADC_Keywords: Exoplanets; Stars, M-type; Stars, dwarfs; Spectra, optical;
Radial velocities
Keywords: Planetary system formation; Exoplanet structure; Radial velocity
Transit photometry; Low mass stars
Abstract:
Studies of close-in planets orbiting M dwarfs have suggested that the
M-dwarf radius valley may be well explained by distinct formation
timescales between enveloped terrestrials and rocky planets that form
at late times in a gas-depleted environment. This scenario is at odds
with the picture that close-in rocky planets form with a primordial
gaseous envelope that is subsequently stripped away by some thermally
driven mass-loss process. These two physical scenarios make unique
predictions of the rocky/enveloped transition's dependence on orbital
separation such that studying the compositions of planets within the
M-dwarf radius valley may be able to establish the dominant physics.
Here, we present the discovery of one such keystone planet: the
ultra-short-period planet TOI-1634b (P=0.989days, F=121F⊕,
rp=1.790-0.081+0.080R⊕) orbiting a nearby M2 dwarf
(Ks=8.7, Rs=0.450R☉, Ms=0.502M☉) and whose size and
orbital period sit within the M-dwarf radius valley. We confirm the
TESS-discovered planet candidate using extensive ground-based
follow-up campaigns, including a set of 32 precise radial velocity
measurements from HARPS-N. We measure a planetary mass of
4.91-0.70+0.68M⊕, which makes TOI-1634b inconsistent with an
Earth-like composition at 5.9σ and thus requires either an
extended gaseous envelope, a large volatile-rich layer, or a rocky
composition that is not dominated by iron and silicates to explain its
mass and radius. The discovery that the bulk composition of TOI-1634b
is inconsistent with that of Earth supports the gas-depleted formation
mechanism to explain the emergence of the radius valley around M
dwarfs with Ms≲0.5M☉.
Description:
We obtained 32 spectra of TOI-1634 using the HARPS-N spectrograph
located at the 3.6m Telescopio Nazionale Galileo (TNG) on La Palma,
Canary Islands. HARPS-N is a high-resolution (R=115000) optical
echelle spectrograph whose long-term pressure and temperature
stability enable it to reach sub-meter-per-second stability. The
exposure time was fixed to 1800s between UT 2020 August 7 and 2021
March 4.
Objects:
---------------------------------------------------------------
RA (2000) DE Designation(s) (Period)
---------------------------------------------------------------
03 45 33.75 +37 06 44.21 TOI-1634 = TIC 201186294 (P=0.989d)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 57 32 HARPS-N time series of TOI-1634
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See also:
I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)
IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)
J/ApJ/720/1118 : i-band photometry of HAT-P-16 (Buchhave+, 2010)
J/A+A/529/A75 : Limb-darkening coefficients (Claret+, 2011)
J/AJ/142/19 : Speckle observations of KOI (Howell+, 2011)
J/ApJS/200/15 : HARPS-TERRA project. I. (Anglada-Escude+, 2012)
J/A+A/549/A109 : HARPS XXXI. The M-dwarf sample (Bonfils+, 2013)
J/ApJS/208/9 : Intrinsic colors and temperatures of PMS stars (Pecaut+, 2013)
J/AJ/148/64 : HAZMAT. I. FUV & NUV emission in early M stars (Shkolnik+, 2014)
J/A+A/573/A101 : Generalised Lomb-Scargle periodogram code (Mortier+, 2015)
J/A+A/575/A119 : HARPS RV and stellar activity (Astudillo-Defru+, 2015)
J/ApJ/804/64 : Empirical and model parameters of 183 M dwarfs (Mann+, 2015)
J/ApJ/807/45 : Potentially habitable planets orbiting Mdwarfs (Dressing+, 2015)
J/AJ/152/141 : Solar neighborhood. XXXVII. RVs for M dwarfs (Benedict+, 2016)
J/AJ/152/180 : Bolometric fluxes eclipsing binaries in Tycho-2 (Stassun+, 2016)
J/MNRAS/457/2877 : Kepler M dwarf stars revised properties (Gaidos+, 2016)
J/A+A/600/A13 : HARPS M dwarf sample magnetic activity (Astudillo-Defru+, 2017)
J/AJ/153/136 : Planets and their host stars with Gaia plxes (Stassun+, 2017)
J/AJ/154/109 : California-Kepler Survey. III. Planet radii (Fulton+, 2017)
J/AJ/154/237 : HARPS-N radial velocities of WASP-47 (Vanderburg+, 2017)
J/ApJ/834/85 : Hα emission in nearby M dwarfs (Newton+, 2017)
J/A+A/618/A142 : Radial velocity for GJ 1132 (Bonfils+, 2018)
J/A+A/619/A1 : 55 Cnc radial velocities and photometry (Bourrier+, 2018)
J/AJ/156/264 : California-Kepler Survey. VII. Planet radius gap (Fulton+, 2018)
J/AJ/156/18 : APOGEE DR14:Binary comp. of evolved stars (Price-Whelan+, 2018)
J/A+A/621/A49 : K2-18 HARPS time-series (Cloutier+, 2019)
J/A+A/628/A39 : Radial velocities of GJ 357 (Luque+, 2019)
J/A+A/629/A111 : L 98-59 (TOI 175) HARPS observations (Cloutier+, 2019)
J/A+A/630/A89 : WASP-12b and WASP-43b griz light curves (Parviainen+, 2019)
J/AJ/158/75 : Mid-type M dwarfs planet occur. rates (Hardegree-Ullman+, 2019)
J/ApJ/875/29 : Spectroscopic analysis of the CKS sample. I. (Martinez+, 2019)
J/A+A/642/A236 : GJ 3473 (TOI-488) radial velocity curve (Kemmer+, 2020)
J/AN/341/996 : Stellar companions of (C)TOIs (Mugrauer+, 2020)
J/AJ/159/211 : Exoplanet parameters from Kepler and K2 (Cloutier+, 2020)
J/AJ/160/3 : Radial velocities of M-dwarf LTT 3780 with HARPS (Cloutier+, 2020)
J/AJ/160/22 : TOI-1235 Radial velocities & optical spectro. (Cloutier+, 2020)
J/A+A/649/A3 : Gaia Early Data Release 3 photometric passbands (Riello+, 2021)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 11 F11.6 d BJD [2068/2279] Observation time; BJD-2457000
13- 19 F7.3 m/s RVel [-12.1/7.34] HARPS-N barycentric radial velocity
21- 25 F5.3 m/s e_RVel [1/3] Uncertainty in RVel
27- 31 F5.3 km/s FWHM [2.96/3.08] FWHM
33- 39 F7.3 km/s BIS [-13.6/8.78] HARPS cross-correlation function
bisector span
41- 45 F5.3 --- Halpha [0.86/0.92] Hα index, unitless
47- 51 F5.3 --- NaD1 [0.44/0.55] Sodium doublet index, Na D1, 5890A
53- 57 F5.3 --- NaD2 [0.58/0.68] Sodium doublet index, Na D2, 5896A
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 23-Nov-2021