J/AJ/161/56 The TESS-Keck Survey. II. RVs of TOI-561 (Weiss+, 2021)
The TESS-Keck Survey.
II. An ultra-short-period rocky planet and its siblings transiting the galactic
thick-disk star TOI-561.
Weiss L.M., Dai F., Huber D., Brewer J.M., Collins K.A., Ciardi D.R.,
Matthews E.C., Ziegler C., Howell S.B., Batalha N.M., Crossfield I.J.M.,
Dressing C., Fulton B., Howard A.W., Isaacson H., Kane S.R., Petigura E.A.,
Robertson P., Roy A., Rubenzahl R.A., Twicken J.D., Claytor Z.R.,
Stassun K.G., MacDougall M.G., Chontos A., Giacalone S., Dalba P.A.,
Mocnik T., Hill M.L., Beard C., Akana Murphy J.M., Rosenthal L.J.,
Behmard A., Van Zandt J., Lubin J., Kosiarek M.R., Lund M.B.,
Christiansen J.L., Matson R.A., Beichman C.A., Schlieder J.E.,
Gonzales E.J., Briceno C., Law N., Mann A.W., Collins K.I., Evans P.,
Fukui A., Jensen E.L.N., Murgas F., Narita N., Palle E., Parviainen H.,
Schwarz R.P., Tan T.-G., Acton J.S., Bryant E.M., Chaushev A., Gill S.,
Eigmuller P., Jenkins J., Ricker G., Seager S., Winn J.N.
<Astron. J., 161, 56 (2021)>
=2021AJ....161...56W 2021AJ....161...56W
ADC_Keywords: Exoplanets; Stars, metal-deficient; Spectra, optical;
Radial velocities
Keywords: Exoplanets ; Exoplanet astronomy ; Exoplanet systems ;
Exoplanet detection methods ; Exoplanet structure ;
Exoplanet formation ; Exoplanet evolution
Abstract:
We report the discovery of TOI-561, a multiplanet system in the
galactic thick disk that contains a rocky, ultra-short-period planet.
This bright (V=10.2) star hosts three small transiting planets
identified in photometry from the NASA TESS mission: TOI-561b
(TOI-561.02, P=0.44days, Rp=1.45±0.11R⊕), c (TOI-561.01,
P=10.8days, Rp=2.90±0.13R⊕), and d (TOI-561.03, P=16.3days,
Rp=2.32±0.16R⊕). The star is chemically
([Fe/H]=-0.41±0.05, [α/Fe]=+0.23±0.05) and kinematically
consistent with the galactic thick-disk population, making TOI-561 one
of the oldest (10±3Gyr) and most metal-poor planetary systems
discovered yet. We dynamically confirm planets b and c with radial
velocities from the W.M.Keck Observatory High Resolution Echelle
Spectrometer. Planet b has a mass and density of 3.2±0.8M⊕
and 5.5-1.6+2.0g/cm3, consistent with a rocky composition. Its
lower- than-average density is consistent with an iron-poor
composition, although an Earth-like iron-to-silicates ratio is not
ruled out. Planet c is 7.0±2.3M⊕ and 1.6±0.6g/cm3,
consistent with an interior rocky core overlaid with a low-mass
volatile envelope. Several attributes of the photometry for planet d
(which we did not detect dynamically) complicate the analysis, but we
vet the planet with high-contrast imaging, ground-based photometric
follow-up, and radial velocities. TOI-561b is the first rocky world
around a galactic thick-disk star confirmed with radial velocities and
one of the best rocky planets for thermal emission studies.
Description:
We obtained 60 high-resolution spectra with the W.M.Keck Observatory
High Resolution Echelle Spectrometer (HIRES) instrument on Maunakea,
Hawaii between 2019 May and 2020 October, at a cadence of one to two
radial velocity (RVs) per night. We followed the standard observing
and data reduction procedures of the California Planet Search (CPS).
We obtained spectra with the C2 decker, which has dimensions of
14"x0.86" and spectral resolution R∼60000 at 500nm.
Objects:
--------------------------------------------
RA (2000) DE Designation(s)
--------------------------------------------
09 52 44.55 +06 12 58.9 TOI-561 = TOI-561
--------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 36 62 Radial Velocities
--------------------------------------------------------------------------------
See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+A/415/155 : Oxygen abundances in the Galactic disk (Bensby+, 2004)
J/A+A/433/185 : Detailed abund. analysis of 102 F and G dwarfs (Bensby+, 2005)
J/A+A/512/A54 : Teff and Fbol from Infrared Flux Method (Casagrande+, 2010)
J/ApJ/725/875 : Chromospheric activity for CPS stars (Isaacson+, 2010)
J/AJ/142/19 : Speckle observations of KOI (Howell+, 2011)
J/A+A/545/A32 : Chemical abundances of 1111 FGK stars (Adibekyan+, 2012)
J/other/Nat/486.375 : Stellar parameters of KOI stars (Buchhave+, 2012)
J/ApJ/776/67 : Rotational tracks (van Saders+, 2013)
J/A+A/562/A71 : Chemical abund. of solar neighbourhood dwarfs (Bensby+, 2014)
J/ApJ/789/154 : Kepler-10 RV measurements by HARPS-N (Dumusque+, 2014)
J/AJ/148/54 : The Hypatia Catalog ((Hinkel+, 2014)
J/ApJ/787/47 : 106 Kepler ultra-short-period planets (Sanchis-Ojeda+, 2014)
J/ApJS/225/32 : Extended abundance analysis of cool stars (Brewer+, 2016)
J/AJ/154/226 : Photometry and radial velocities of K2-131 (Dai+, 2017)
J/AJ/153/71 : Kepler follow-up observation program I Imaging (Furlan+, 2017)
J/ApJ/844/102 : KIC star plxs from asteroseismology vs Gaia (Huber+, 2017)
J/AJ/153/136 : Planets and host stars with Gaia parallaxes (Stassun+, 2017)
J/ApJ/836/77 : Library of high-S/N optical spectra of FGKM stars (Yee+, 2017)
J/MNRAS/473/2004 : TESS-HERMES Survey Data Release 1 catalog (Sharma+, 2018)
J/AJ/156/102 : TESS Input Catalog and Candidate Target List (Stassun+, 2018)
J/AJ/155/235 : Speckle interferometry SOAR in 2016 & 2017 (Tokovinin+, 2018)
J/AJ/155/48 : California-Kepler Survey V. Masses and radii (Weiss+, 2018)
J/A+A/636/A58 : L 168-9 radial velocity curve (Astudillo-Defru+, 2020)
J/AJ/159/241 : TESS-Keck Survey. I. HD332231 Radial Velocities (Dalba+, 2020)
J/AJ/159/239 : Transmission Spectroscopy Metric of exoplanets (Guo+, 2020)
J/AJ/160/138 : 68 Gaia DR2 ultra-short-period planet host stars (Hamer+,2020)
J/AJ/159/19 : SOAR TESS survey. I. (Ziegler+, 2020)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
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1- 14 F14.6 d BJD [2458599/2459183] Barycentric Julian Date
16- 20 F5.1 m/s RVel [-11.3/9.5] Radial velocity
22- 24 F3.1 m/s e_RVel [1.1/1.9] Uncertainty in RVel
26- 30 F5.3 --- S-Val [0.12/0.16] Mt. Wilson S-Value (1)
32- 36 F5.3 --- e_S-Val [0.001] Uncertainty in SVal
--------------------------------------------------------------------------------
Note (1): Indicator of chromospheric magnetic activity.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Dalba et al. Paper I. 2020AJ....159..241D 2020AJ....159..241D Cat. J/AJ/159/241
Weiss et al. Paper II. 2021AJ....161...56W 2021AJ....161...56W This catalog
Dai et al. Paper III. 2020AJ....160..193D 2020AJ....160..193D
Rubenzahl et al. Paper IV. 2021AJ....161..119R 2021AJ....161..119R Cat. J/AJ/161/119
Scarsdale et al. Paper V. 2021AJ....162..215S 2021AJ....162..215S Cat. J/AJ/162/215
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(End) Prepared by [AAS], Coralie Fix [CDS], 25-Mar-2021