J/AJ/161/97 Radial Velocities of TOI-811 and TOI-852 (Carmichael+, 2021)
TOI-811b and TOI-852b: new transiting brown dwarfs with similar masses and very
different radii and ages from the TESS mission.
Carmichael T.W., Quinn S.N., Zhou G., Grieves N., Irwin J.M., Stassun K.G.,
Vanderburg A.M., Winn J.N., Bouchy F., Brasseur C.E., Briceno C.,
Caldwell D.A., Charbonneau D., Collins K.A., Colon K.D., Eastman J.D.,
Fausnaugh M., Fong W., Furesz G., Huang C., Jenkins J.M., Kielkopf J.F.,
Latham D.W., Law N., Lund M.B., Mann A.W., Ricker G.R., Rodriguez J.E.,
Schwarz R.P., Shporer A., Tenenbaum P., Wood M.L., Ziegler C.
<Astron. J., 161, 97 (2021)>
=2021AJ....161...97C 2021AJ....161...97C
ADC_Keywords: Stars, brown dwarf; Exoplanets; Spectra, optical;
Radial velocities
Keywords: Brown dwarfs ; Radial velocity ; Transit photometry ; Spectroscopy ;
Photometry ; Substellar companion stars
Abstract:
We report the discovery of two transiting brown dwarfs (BDs), TOI-811b
and TOI-852b, from NASA's Transiting Exoplanet Survey Satellite
mission. These two transiting BDs have similar masses but very
different radii and ages. Their host stars have similar masses,
effective temperatures, and metallicities. The younger and larger
transiting BD is TOI-811b at a mass of Mb=59.9±13.0MJ and radius
of Rb=1.26±0.06RJ, and it orbits its host star in a period of
P=25.16551±0.00004days. We derive the host star's age of
93-29+61Myr from an application of gyrochronology. The youth of
this system, rather than external heating from its host star, is why
this BD's radius is relatively large. This constraint on the youth of
TOI-811b allows us to test substellar mass-radius evolutionary models
at young ages where the radius of BDs changes rapidly. TOI-852b has a
similar mass at Mb=53.7±1.4MJ but is much older (4 or 8Gyr,
based on bimodal isochrone results of the host star) and is also
smaller with a radius of Rb=0.83±0.04RJ. TOI-852b's orbital
period is P=4.94561±0.00008days. TOI-852b joins the likes of other
old transiting BDs that trace out the oldest substellar mass-radius
evolutionary models where contraction of the BD's radius slows and
approaches a constant value. Both host stars have a mass of
M*=1.32M☉±0.05 and differ in their radii, Teff, and [Fe/H],
with TOI-811 having R*=1.27±0.09R☉, Teff=6107±77K, and
[Fe/H]=0.40±0.09 and TOI-852 having R*=1.71±0.04R☉,
Teff=5768±84K, and [Fe/H]=0.33±0.09. We take this opportunity
to examine how TOI-811b and TOI-852b serve as test points for young
and old substellar isochrones, respectively.
Description:
To characterize the Radial Velocities of TOI-811, we obtained a series
of 11 spectroscopic observations using the CHIRON spectrograph on the
1.5m Small and Moderate Aperture Research Telescope System (SMARTS)
telescope, located at Cerro Tololo Inter-American Observatory (CTIO),
Chile. CHIRON has a resolving power of R∼80000 over the wavelength
region 4100-8700Å.
We use the Tillinghast Reflector Echelle Spectrograph (TRES)
instrument on Mount Hopkins, Arizona, to obtain spectra for both
TOI-811 and TOI-852. TRES has a resolving power of R∼44000 and covers
a wavelength range of 3900-9100Å.
We obtained 11 spectroscopic observations of TOI-852 from 2019 August
4 to 26 with the high-resolution CORALIE spectrograph on the Swiss
1.2m Euler telescope at the La Silla Observatory, Chile. CORALIE has a
resolving power of R∼60000.
Objects:
---------------------------------------------------------
RA (2000) DE Designation(s) (Period)
---------------------------------------------------------
05 52 07.26 -32 55 30.7 TOI-811 = TOI-811 (P=25.166d)
01 38 57.66 -07 16 51.3 TOI-852 = TOI-852 (P=4.946d)
---------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 40 37 Relative radial velocities of TOI-811 from CHIRON
and of TOI-852 from TRES and CORALIE
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See also:
I/259 : The Tycho-2 Catalogue (Hog+ 2000)
IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/ApJS/141/503 : Radial Velocities for 889 late-type stars (Nidever+, 2002)
J/A+A/392/215 : The CORALIE survey for extrasolar planets. IX. (Santos+,2002)
J/MNRAS/349/757 : Masses, ages and metallicities of F-G dwarfs (Lambert+, 2004)
J/A+A/491/889 : CoRoT-Exo-3b observations (Deleuil+, 2008)
J/ApJ/687/1264 : Age estimation for solar-type dwarfs (Mamajek+, 2008)
J/ApJ/718/1353 : Light curve of the triple system NLTT 41135 (Irwin+, 2010)
J/ApJ/757/18 : RVel for 16 hot Jupiter host stars (Albrecht+, 2012)
J/other/Nat/486.375 : Stellar parameters of KOI stars (Buchhave+, 2012)
J/ApJ/761/123 : KELT-1 photometry and spectroscopy follow-up (Siverd+, 2012)
J/A+A/549/A18 : WASP-30 and J1219-39 light & velocity curves (Triaud+, 2013)
J/AJ/153/15 : Photometry and spectroscopy of EPIC 201702477 (Bayliss+,2017)
J/ApJ/836/77 : Library of high-S/N optical spectra of FGKM stars (Yee+,2017)
J/A+A/613/A63 : Lithium content for 148 Pleiades stars (Bouvier+, 2018)
J/ApJ/856/23 : BANYAN. XI. The BANYAN Σ algorithm (Gagne+, 2018)
J/AJ/156/140 : 4 new eclipsing mid M-dwarf systems from MEarth (Irwin+,2018)
J/AJ/156/102 : TESS Input Catalog and Candidate Target List (Stassun+, 2018)
J/AJ/158/38 : Substellar discoveries from Kepler & K2 (Carmichael+, 2019)
J/A+A/628/A64 : EPIC 212036875b griz light curves (Persson+, 2019)
J/AJ/157/31 : Differential photometry & RVel of HATS-70 (Zhou+, 2019)
J/AJ/159/19 : SOAR TESS survey. I. (Ziegler+, 2020)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 11 F11.6 d BJD [8582/8874] Barycentric Julian Date, TBD; BJD-2450000
13- 18 I6 m/s RVel [-22141/36734] Radial Velocity
20- 24 F5.1 m/s e_RVel [19.9/168] Error on RVel
26- 32 A7 --- Inst Instrument used; CHIRON, TRES or CORALIE (1)
34- 40 A7 --- TOI Target star identification
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Note (1): The offsets γ for each instrument are free parameters in our
EXOFASTv2 analysis
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History:
From electronic version of the journal
(End) Prepared by Coralie Fix [CDS], 10-May-2021