J/AJ/160/3 Radial velocities of M-dwarf LTT 3780 with HARPS (Cloutier+, 2020)
A pair of TESS planets spanning the radius valley around the nearby mid-M dwarf
LTT3780.
Cloutier R., Eastman J.D., Rodriguez J.E., Astudillo-Defru N., Bonfils X.,
Mortier A., Watson C.A., Stalport M., Pinamonti M., Lienhard F.,
Harutyunyan A., Damasso M., Latham D.W., Collins K.A., Massey R., Irwin J.,
Winters J.G., Charbonneau D., Ziegler C., Matthews E., Crossfield I.J.M.,
Kreidberg L., Quinn S.N., Ricker G., Vanderspek R., Seager S., Winn J.,
Jenkins J.M., Vezie M., Udry S., Twicken J.D., Tenenbaum P., Sozzetti A.,
Segransan D., Schlieder J.E., Sasselov D., Santos N.C., Rice K.,
Rackham B.V., Poretti E., Piotto G., Phillips D., Pepe F., Molinari E.,
Mignon L., Micela G., Melo C., de Medeiros J.R., Mayor M., Matson R.A.,
Martinez Fiorenzano A.F., Mann A.W., Magazzu A., Lovis C., Lopez-Morales M.,
Lopez E., Lissauer J.J., Lepine S., Law N., Kielkopf J.F., Johnson J.A.,
Jensen E.L.N., Howell S.B., Gonzales E., Ghedina A., Forveille T.,
Figueira P., Dumusque X., Dressing C.D., Doyon R., Diaz R.F., Di
Fabrizio L., Delfosse X., Cosentino R., Conti D.M., Collins K.I.,
Cameron A.C., Ciardi D., Caldwell D.A., Burke C., Buchhave L., Briceno C.,
Boyd P., Bouchy F., Beichman C., Artigau E., Almenara J.M.
<Astron. J., 160, 3 (2020)>
=2020AJ....160....3C 2020AJ....160....3C
ADC_Keywords: Exoplanets; Stars, M-type; Stars, dwarfs; Spectra, optical;
Radial velocities
Keywords: Radial velocity ; M dwarf stars ; Exoplanet systems ;
Transit photometry
Abstract:
We present the confirmation of two new planets transiting the nearby
mid-M dwarf LTT3780 (TIC36724087, TOI-732, V=13.07, Ks=8.204,
Rs=0.374R☉, Ms=0.401 M☉, d=22pc). The two planet candidates
are identified in a single Transiting Exoplanet Survey Satellite
sector and validated with reconnaissance spectroscopy, ground-based
photometric follow-up, and high-resolution imaging. With measured
orbital periods of Pb=0.77, Pc=12.25days and sizes
rp,b=1.33±0.07, rp,c=2.30±0.16R{earth}, the two planets
span the radius valley in period-radius space around low-mass stars,
thus making the system a laboratory to test competing theories of the
emergence of the radius valley in that stellar mass regime. By
combining 63 precise radial velocity measurements from the High
Accuracy Radial velocity Planet Searcher (HARPS) and HARPS-N, we
measure planet masses of mp,b=2.62-0.46+0.48 and
mp,c=8.6-1.3+1.6M{earth}, which indicates that LTT3780b has a
bulk composition consistent with being Earth-like, while LTT3780c
likely hosts an extended H/He envelope. We show that the recovered
planetary masses are consistent with predictions from both
photoevaporation and core-powered mass-loss models. The brightness and
small size of LTT3780, along with the measured planetary parameters,
render LTT3780b and c as accessible targets for atmospheric
characterization of planets within the same planetary system and
spanning the radius valley.
Description:
We obtained 33 spectra of LTT3780 with the High Accuracy Radial
velocity Planet Searcher (HARPS) echelle spectrograph mounted at the
European Southern Observatory (ESO) 3.6m telescope at La Silla
Observatory, Chile, at R=115000. The observations were taken between
UT-2019-June-21 and 2020-February-24 as part of the ESO program
1102.C-0339. The exposure time was set to 2400s.
We obtained 30 spectra of LTT3780 with the HARPS Northern hemisphere
(HARPS-N) optical echelle spectrograph at the Telescopio Nazionale
Galileo (TNG) on La Palma in the Canary Islands. The observations were
taken as part of the HARPS-N Collaboration Guaranteed Time
Observations program between UT-2019 December-14 and 2020-March-15.
The exposure time was set to 1800s.
Objects:
--------------------------------------------------------
RA (ICRS) DE Designation(s) (Period)
--------------------------------------------------------
10 18 35.14 -11 43 00.2 LTT3780 = LTT 3780 (P=104)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 33 63 Radial velocity time series of LTT 3780 from
HARPS & HARPS-N
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See also:
II/328 : AllWISE Data Release (Cutri+ 2013)
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/A+A/442/211 : Spectroscopic distances of 322 NLTT stars (Scholz+, 2005)
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/ApJS/200/15 : HARPS-TERRA project. I. (Anglada-Escude+, 2012)
J/ApJ/796/127 : Spitzer h and χ Persei candidate members (Cloutier+, 2014)
J/ApJS/210/20 : Small Kepler planets radial velocities (Marcy+, 2014)
J/ApJ/807/45 : Habitable planets orbiting M dwarfs (Dressing+, 2015)
J/ApJ/804/64 : Empirical and model parameters of 183 M dwarfs (Mann+, 2015)
J/ApJ/809/25 : Stellar and planet properties for K2 candidates (Montet+,2015)
J/AJ/152/141 : Solar neighborhood. XXXVII. RVs for M dwarfs (Benedict+, 2016)
J/A+A/600/A13 : HARPS M dwarf sample magnetic activity (Astudillo-Defru+,2017)
J/ApJ/834/17 : Mass & radius of planets, moons, low mass stars (Chen+, 2017)
J/AJ/154/109 : California-Kepler Survey . III. Planet radii (Fulton+, 2017)
J/A+A/618/A142 : Radial velocity for GJ 1132 (Bonfils+, 2018)
J/A+A/615/A69 : K2-3 system characterized with HARPS-N & HARPS (Damasso+,2018)
J/AJ/155/136 : Planets orbiting bright stars K2 campaigns 0-10 (Mayo+, 2018)
J/AJ/155/180 : A catalog of cool dwarf targets for the TESS (Muirhead+, 2018)
J/AJ/156/102 : The TESS Input Catalog & Candidate Target List (Stassun+,2018)
J/AJ/157/43 : WASP-161b, WASP-163b and WASP-170b (Barkaoui+, 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/627/A43 : Two super-Earths orbiting TOI-402 (Dumusque+, 2019)
J/AJ/158/75 : Mid-type M dwarfs planet occur. rates (Hardegree-Ullman+,2019)
J/A+A/623/A114 : Light curve of K2-292 (HD 119130) (Luque+, 2019)
J/A+A/636/A58 : L 168-9 radial velocity curve (Astudillo-Defru+, 2020)
J/AJ/159/211 : Exoplanets parameters from Kepler and K2 (Cloutier+, 2020)
J/ApJS/247/28 : K2 star parameters from Gaia & LAMOST (Hardegree-Ullman+,2020)
J/AJ/159/19 : SOAR TESS survey. I. (Ziegler+, 2020)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 11 F11.6 d BJD [1656/1924] Baricentric Julian Date; BJD-2457000
13- 19 F7.3 m/s RVel [-10.1/10.6] Radial Velocity
21- 25 F5.3 m/s e_RVel [0.79/2.5] Uncertainty in RVel
27- 33 A7 --- Inst Instrument HARPS (33 occurrences) or HARPS-N
(30 occurrences)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 30-Sep-2020