J/AJ/167/109 TOI-1994 radial velocities with MINERVA & CHIRON (Page+, 2024)
TOI-1994b: A Low-mass Eccentric Brown Dwarf Transiting A Subgiant Star.
Page E., Pepper J., Wright D., Rodriguez J.E., Wittenmyer R.A., Kane S.R.,
Addison B., Bedding T., Bowler B.P., Barclay T., Collins K.A., Evans P.,
Horner J., Jensen E.L.N., Johnson M.C., Kielkopf J., Mireles I.,
Plavchan P., Quinn S.N., Seager S., Shporer A., Stassun K.G., Striegel S.,
Winn J.N., Zhou G., Ziegler C.
<Astron. J., 167, 109 (2024)>
=2024AJ....167..109P 2024AJ....167..109P
ADC_Keywords: Exoplanets; Stars, brown dwarf; Spectra, optical;
Radial velocities
Keywords: Brown dwarfs ; Photometry ; Radial velocity ; Substellar
companion stars
Abstract:
We present the discovery of TOI-1994b, a low-mass brown dwarf
transiting a hot subgiant star on a moderately eccentric orbit.
TOI-1994 has an effective temperature of 7700-410+720K, Vmagnitude
of 10.51mag and logg of 3.982-0.065+0.067. The brown dwarf has a
mass of 22.1-2.5+2.6MJup, a period of 4.034days, an eccentricity
of 0.341-0.059+0.054, and a radius of 1.220-0.071+0.082RJup.
TOI-1994b is more eccentric than other transiting brown dwarfs with
similar masses and periods. The population of low-mass brown dwarfs
may have properties similar to planetary systems if they were formed
in the same way, but the short orbital period and high eccentricity of
TOI-1994b may contrast this theory. An evolved host provides a
valuable opportunity to understand the influence stellar evolution has
on the substellar companion's fundamental properties. With precise
age, mass, and radius, the global analysis and characterization of
TOI-1994b augments the small number of transiting brown dwarfs and
allows the testing of substellar evolution models.
Description:
TOI-1994b was spectroscopically observed by the MINERVA-Australis
telescope array in Toowoomba, Australia at the University of Southern
Queensland's Mount Kent Observatory. The telescopes T3, T4 and T5 were
used for spectroscopic observations of TOI-1994. Each
MINERVA-Australis telescope uses fiber optic cables to feed light into
a spectrograph reaching resolution R=80000 for wavelengths from 480 to
630nm. A total of 47 spectra were taken by MINERVA-Australis between
2021 June 5 and 2021 July 12 with an exposure time of 3600s.
We also collected a 23 measurements with the CHIRON spectrograph on
the 1.5m SMARTS telescope at CTIO in Chile. The observations were
obtained between 2021 November 6 and 2022 May 1, resulting in full
phase coverage for the orbit of TOI-1994b. We employed the fiber-fed
image slicer to yield a resolving power of R∼80000 between 4100 and
8700Å. The typical exposure time was 800s and resulted in a mean
S/N per resolution element of 65.
Objects:
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RA (2000) DE Designation(s) (Period)
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09 48 41.92 -51 45 23.6 TOI-1994 = 2MASS J09484191-5145236 (P=4.034d)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 32 66 Radial velocity observations of TOI-1994
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)
J/ApJ/640/1051 : 25pc sample of Sun-like stars (Grether+, 2006)
J/ApJ/718/1353 : Light curve of the triple system NLTT 41135 (Irwin+, 2010)
J/A+A/525/A95 : Search for brown-dwarf companions of stars (Sahlmann+, 2011)
J/AJ/156/140 : 4 eclipsing mid M-dwarf systems from MEarth (Irwin+, 2018)
J/AJ/156/102 : TESS Input Catalog & Candidate Target List (Stassun+, 2018)
J/MNRAS/485/2380 : Gaia-derived luminosities Kepler A/F stars (Murphy+, 2019)
J/AJ/161/97 : Radial Velocities of TOI-811 and TOI-852 (Carmichael+, 2021)
J/A+A/652/A127 : 13-150MJup eclipsing bins transiting comp. (Grieves+, 2021)
J/ApJS/254/39 : Exoplanet candidates from TESS 1st 2yr obs (Guerrero+, 2021)
J/A+A/645/A7 : Determining mass of RV exoplanets with Gaia (Kiefer+, 2021)
J/AJ/162/176 : The solar neighborhood. XLVIII. (Paredes+, 2021)
J/A+A/664/A94 : 8 TOI RV curves and 2 TOI light curves (Psaridi+, 2022)
J/AJ/165/268 : Radial velocity & rotation period HIP33069b (Vowell+, 2023)
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 F10.5 d BJD [9370/9655] Barycentric Julian Date, BJD
at TDB-2450000.0
12- 16 I5 m.s-1 RVel [-3742/3112] Radial velocity
18- 21 I4 m.s-1 e_RVel [228/1565] Uncertainty in RVel
23- 32 A10 --- Inst Instrument used (CHIRON or MINERVA)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 14-May-2024