J/AJ/160/22 TOI-1235 Radial velocities & optical spectroscopy (Cloutier+, 2020)
TOI-1235 b: a keystone super-Earth for testing radius valley emergence models
around early M dwarfs.
Cloutier R., Rodriguez J.E., Irwin J., Charbonneau D., Stassun K.G.,
Mortier A., Latham D.W., Isaacson H., Howard A.W., Udry S., Wilson T.G.,
Watson C.A., Pinamonti M., Lienhard F., Giacobbe P., Guerra P.,
Collins K.A., Beiryla A., Esquerdo G.A., Matthews E., Matson R.A.,
Howell S.B., Furlan E., Crossfield I.J.M., Winters J.G., Nava C., Ment K.,
Lopez E.D., Ricker G., Vanderspek R., Seager S., Jenkins J.M., Ting E.B.,
Tenenbaum P., Sozzetti A., Sha L., Segransan D., Schlieder J.E.,
Sasselov D., Roy A., Robertson P., Rice K., Poretti E., Piotto G.,
Phillips D., Pepper J., Pepe F., Molinari E., Mocnik T., Micela G.,
Mayor M., Martinez Fiorenzano A.F., Mallia F., Lubin J., Lovis C.,
Lopez-Morales M., Kosiarek M.R., Kielkopf J.F., Kane S.R., Jensen E.L.N.,
Isopi G., Huber D., Hill M.L., Harutyunyan A., Gonzales E., Giacalone S.,
Ghedina A., Ercolino A., Dumusque X., Dressing C.D., Damasso M., Dalba P.A.,
Cosentino R., Conti D.M., Colon K.D., Collins K.I., Cameron A.C., Ciardi D.,
Christiansen J., Chontos A., Cecconi M., Caldwell D.A., Burke C.,
Buchhave L., Beichman C., Behmard A., Beard C., Akana Murphy J.M.
<Astron. J., 160, 22 (2020)>
=2020AJ....160...22C 2020AJ....160...22C
ADC_Keywords: Stars, dwarfs; Stars, M-type; Spectra, optical; Photometry;
Radial velocities; Exoplanets
Keywords: Radial velocity ; M dwarf stars ; Transit photometry ;
Exoplanet formation ; Exoplanet structure
Abstract:
Small planets on close-in orbits tend to exhibit envelope mass
fractions of either effectively zero or up to a few percent depending
on their size and orbital period. Models of thermally driven
atmospheric mass loss and of terrestrial planet formation in a
gas-poor environment make distinct predictions regarding the location
of this rocky/nonrocky transition in period-radius space. Here we
present the confirmation of TOI-1235b (P=3.44days,
rp=1.738-0.076+0.087R⊕), a planet whose size and period
are intermediate between the competing model predictions, thus making
the system an important test case for emergence models of the
rocky/nonrocky transition around early M dwarfs
(Rs=0.630±0.015R☉, Ms=0.640±0.016M☉). We
confirm the TESS planet discovery using reconnaissance spectroscopy,
ground-based photometry, high- resolution imaging, and a set of 38
precise radial velocities (RVs) from HARPS-N and HIRES. We measure a
planet mass of 6.91-0.85+0.75M⊕, which implies an iron
core mass fraction of 20-12+15% in the absence of a gaseous
envelope. The bulk composition of TOI-1235b is therefore consistent
with being Earth-like, and we constrain an H/He envelope mass fraction
to be <0.5% at 90% confidence. Our results are consistent with model
predictions from thermally driven atmospheric mass loss but not with
gas-poor formation, suggesting that the former class of processes
remains efficient at sculpting close-in planets around early M dwarfs.
Our RV analysis also reveals a strong periodicity close to the first
harmonic of the photometrically determined stellar rotation period
that we treat as stellar activity, despite other lines of evidence
favoring a planetary origin (P=21.8-0.8+0.9days,
mpsini=13.0-5.3+3.8M⊕) that cannot be firmly ruled out
by our data.
Description:
TOI-1235 was observed in three nonconsecutive Transiting Exoplanet
Survey Satellite (TESS) sectors between UT 2019 July 18 and 2020
February 18.
MEarth-North has archival images of the field surrounding TOI-1235
that span 7.1yr (UT 2008 October 2to 2015 November 10). MEarth-North
is a telescope array located at the Fred Lawrence Whipple Observatory
(FLWO) on Mount Hopkins, AZ. The facility consists of eight 40cm
telescopes.
We obtained 27 spectra of TOI-1235 with the HARPS-N optical echelle
spectrograph at the 3.6m Telescopio Nazionale Galileo on La Palma in
the Canary Islands (R=115000). The spectra were taken as part of the
HARPS-N Collaboration Guaranteed Time Observations program between UT
2019 December 24 and 2020 March 12. The exposure time was set to 1800s
(440-687nm).
We obtained 11 additional spectra of TOI-1235 with the High Resolution
Echelle Spectrometer on Keck I as part of the TESS-Keck Survey (TKS)
between UT 2019 December 10 and 2020 March 10. HIRES is an optical
spectrograph at R=60000, that perform its precise wavelength
calibration between 500 and 620nm.
Objects:
-------------------------------------------------------
RA (ICRS) DE Designation(s) (Period)
-------------------------------------------------------
10 08 51.81 +69 16 35.6 TOI1235 = TOI 1235 (P=44.7)
-------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 32 38 Radial velocity time series of TOI-1235 from
HARPS-N & HIRES
fig3.dat 32 2064 TOI-1235 differential light curve from archival
MEarth-North photometry
--------------------------------------------------------------------------------
See also:
I/259 : The Tycho-2 Catalogue (Hog+ 2000)
II/335 : Revised catalog of GALEX UV sources (GUVcat_AIS GR6+7)(Bianchi+ 2017)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)
J/AJ/123/2822 : Photometry of southern NLTT stars (Reid+, 2002)
J/MNRAS/370/954 : VRIHalpha photometry of M34 (Irwin+, 2006)
J/A+A/468/1115 : Thorium and argon lines in the visible (Lovis+, 2007)
J/A+A/529/A75 : Limb-darkening coefficients (Claret+, 2011)
J/AJ/142/19 : Speckle observations of KOI (Howell+, 2011)
J/ApJ/743/48 : Stars with Prot and X-ray luminosities (Wright+, 2011)
J/ApJS/200/15 : HARPS-TERRA project. I. (Anglada-Escude+, 2012)
J/A+A/546/A27 : Radial velocity and photometry for GJ3470 (Bonfils+, 2012)
J/ApJ/798/41 : GALEX NUV obs. of bright M-type stars (Ansdell+, 2015)
J/ApJ/800/135 : HARPS-N radial velocities of KOI-69 (Dressing+, 2015)
J/ApJ/804/64 : Empirical and model parameters of 183 M dwarfs (Mann+, 2015)
J/AJ/152/141 : Solar neighborhood. XXXVII. RVs M dwarfs (Benedict+, 2016)
J/ApJ/821/93 : Rot. & Galactic kinematics of mid M dwarfs (Newton+, 2016)
J/AJ/152/180 : Bolom. fluxes of eclipsing bin. in Tycho-2 (Stassun+, 2016)
J/MNRAS/463/1844 : M dwarfs rotation-activity relation (Stelzer+, 2016)
J/AJ/154/109 : California-Kepler Survey III. Planet radii (Fulton+, 2017)
J/ApJ/834/85 : Hα emission in nearby M dwarfs (Newton+, 2017)
J/AJ/153/136 : Planets and their host stars with Gaia plxs (Stassun+, 2017)
J/ApJ/836/77 : Library of high-S/N optical spectra FGKM stars (Yee+, 2017)
J/ApJ/865/68 : Abundances for 79 Sun-like stars within 100pc (Bedell+,2018)
J/A+A/618/A142 : Radial velocity for GJ 1132 (Bonfils+, 2018)
J/A+A/615/A69 : K2-3 system characterized HARPS-N & HARPS (Damasso+, 2018)
J/AJ/156/264 : California-Kepler Survey VII. Planet rad gap (Fulton+, 2018)
J/AJ/155/136 : Planets orbiting bright stars in K2 campaigns (Mayo+, 2018)
J/AJ/155/180 : Catalog of cool dwarf targets for the TESS (Muirhead+, 2018)
J/AJ/156/102 : TESS Input Catalog & Candidate Target List (Stassun+, 2018)
J/AJ/158/81 : Low-mass stars from the first 2 TESS sectors (Cloutier,2019)
J/A+A/629/A111 : L 98-59 (TOI 175) HARPS observations (Cloutier+, 2019)
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/ApJ/874/107 : HARPS-N solar radial velocities & activity (Milbourne+,2019)
J/AJ/159/211 : Exoplanets parameters from Kepler and K2 (Cloutier+, 2020)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 F11.6 d BJD [1828/1922] Barycentric Julian Date, BJD-2457000
13- 18 F6.3 m/s RVel [-7.9/9.7] Radial velocity
20- 24 F5.3 m/s e_RVel [0.81/2.2] Uncertainty in RV
26- 32 A7 --- Inst Instrument used (1)
--------------------------------------------------------------------------------
Note (1): Instruments as follows:
HARPS-N = High Accuracy Radial velocity Planet Searcher for the
Northern hemisphere at the Italian Telescopio Nazionale
Galileo, a 3.58m telescope at Roque de los Muchachos
Observatory, Canary Island, Spain (27 occurrences)
HIRES = High Resolution Spectrograph on Keck 4.145m Telescope in
Hawaii (11 occurrences)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: fig3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 F14.6 d BJD [2454741/2457337] Barycentric Julian Date
16- 23 F8.6 --- Flux [0.89/1.1] Normalized flux
25- 32 F8.6 --- e_Flux [0.001/0.03] Error, Flux
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 02-Oct-2020