J/AJ/170/68 Radial velocities of 11 new brown dwarfs from TESS (Vowell+, 2025)
Eleven new transiting brown dwarfs and very-low-mass stars from TESS.
Vowell N., Rodriguez J.E., Latham D.W., Quinn S.N., Schulte J.,
Eastman J.D., Bieryla A., Barkaoui K., Ciardi D.R., Collins K.A.,
Girardin E., Hebrard G., Heldridge E., Jafariyazani M., Kotten B.,
Mancini L., Murgas F., Narita N., Radford D.J., Relles H.M., Shporer A.,
Soares-Furtado M., Strakhov I.A., Ziegler C., Boisse I., Briceno C.,
Calkins M.L., Clark C.A., Collins K.I., de Leon J., Esquerdo G.A.,
Fajardo-Acosta S.B., Forveille T., Fukui A., Watkins C.N., He R.,
Heidari N., Horne K., Jenkins J.M., Mann A.W., Naponiello L., Palle E.,
Schwarz R.P., Seager S., Southworth J., Srdoc G., Swift J.J., Winn J.N.
<Astron. J., 170, 68 (2025)>
=2025AJ....170...68V 2025AJ....170...68V
ADC_Keywords: Stars, brown dwarf; Radial velocities; Spectroscopy; Optical;
Exoplanets
Keywords: Brown dwarfs ; Exoplanets ; M dwarf stars ; Transits ; Radial velocity
Abstract:
We present the discovery of 11 new transiting brown dwarfs (BDs) and
low-mass M dwarfs from NASA's Transiting Exoplanet Survey Satellite
(TESS) mission: TOI-2844, TOI-3122, TOI-3577, TOI-3755, TOI-4462,
TOI-4635, TOI-4737, TOI-4759, TOI-5240, TOI-5467, and TOI-5882. They
consist of five BD companions and six very-low-mass stellar companions
ranging in mass from 25MJ to 128MJ. We used a combination of
photometric time-series, spectroscopic, and high-resolution imaging
follow-up as a part of the TESS Follow-up Observing Program (or TFOP)
to characterize each system. With over 50 transiting BDs confirmed, we
now have a large enough sample to directly test different formation
and evolutionary scenarios. We provide a renewed perspective on the
transiting "brown dwarf desert" and its role in differentiating
between planetary and stellar formation mechanisms. Our analysis of
the eccentricity distribution for the transiting BD sample does not
support previous claims of a transition between planetary and stellar
formation at ∼42MJ. We also contribute a first look into the
metallicity distribution of transiting companions in the range
7-150MJ, showing that this does not support a ∼42MJ transition
too. Finally, we also detect a significant lithium absorption feature
in one of the BD hosts (TOI-5882). However, we determine that the host
star is likely old based on rotation, kinematic, and photometric
measurements. We therefore claim that TOI-5882 may be a candidate for
planetary engulfment.
Description:
We obtained spectroscopic measurements for each system in this sample
via the Tillinghast Reflector Echelle Spectrograph (TRES) on the
1.5m Tillinghast Reflector telescope at the Fred Lawrence Whipple
Observatory on Mt. Hopkins, Arizona, USA. The TRES instrument is a
fiber-fed, optical echelle spectrograph with a resolving power of
44,000. The measurements were taken between 2021 June and 2023 October.
We complement the TRES data with SOPHIE observations of TOI-5882.
SOPHIE (Spectrographe pour l'Observation des Phenomenes des Interieurs
stellaires et des Exoplanetes) is a stabilized echelle spectrograph at
the 1.93m telescope of the Observatoire de Haute-Provence, France. We
used its high-resolution mode (resolving power R=75,000) and the fast
readout of its CCD. We have a data set of 21 SOPHIE measurements of
TOI-5882 secured from 2022 December to 2024 July. Exposure times
ranged between 5 and 37min, allowing S/Ns between 14 and 40 to be
reached per pixel at 550nm.
The systems presented here were observed by TESS between Sectors 6-76
(12/11/18-03/26/24) with cadences ranging from 30min in the prime
mission to as low as 2min in the extended mission. We then gathered
ground-based time-series photometry of each system as the companion
transited its host star. The observations for these systems were
collected through the TESS Follow-up Observing Program (TFOP;
Collins+2018, J/AJ/156/234) between 2023 and 2025 from various
observatories. The Las Cumbres Observatory Global Telescope (LCOGT)
was responsible for 14 light curves from the following sites: McDonald
Observatory (McD; Texas, USA), Teide Observatory (TEID; Spain), South
African Astronomical Observatory (SAAO), and Cerro Tololo
Inter-American Observatory (CTIO; Chile). The remaining light curves
were contributed by the following facilities: Calar Alto Observatory
(Spain), Brierfield Observatory (Australia), the Telescopio Carlos
Sanchez (TCS) at Teide Observatory (Spain), Grand-Pra (GdP)
Observatory (Switzerland), Thacher Observatory (California, USA),
KeplerCam at the Fred Lawrence Whipple Observatory (FLWO; Arizona,
USA), and the Acton Sky Portal (USA).
We used the ShARCS and PHARO instruments for AO imaging. The ShARCS
instrument is on the Shane 3m telescope located at Lick Observatory
and the PHARO instrument is on the Palomar Hale 5m telescope at
Palomar Observatory, both in California, USA. For our speckle
observations, we used the following telescopes and instruments: HRCam
on the Southern Astrophysical Research (SOAR) 4.1m telescope at CTIO
(Chile), the NN-EXPLORE Exoplanet Stellar Speckle Imager (NESSI) on
the WIYN 3.5m telescope at Kitt Peak Observatory (Arizona, USA), the
Speckle Polarimeter on the 2.5m telescope at the Caucasian Mountain
Observatory of the Sternberg Astronomical Institute (SAI) at Lomonosov
Moscow State University (Russia), and the Zorro instrument on the
Gemini-South 8m telescope (Chile). Our high-resolution imaging runs
took place between 2021 October and 2024 April, and resulted in the
detection of only two nearby companions, one in the TOI-4462 system
and another in the TOI-5240 system.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
targets.dat 21 11 List of targets (Table added by CDS)
table4.dat 48 160 Radial velocity measurements
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
IV/39 : TESS Input Catalog version 8.2 (TIC v8.2) (Paegert+, 2021)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
I/357 : Gaia DR3 Part 3. Non-single stars (Gaia Collaboration, 2022)
J/A+A/398/363 : Statistical properties of exoplanets II (Santos+, 2003)
J/ApJ/622/1102 : The planet-metallicity correlation. (Fischer+, 2005)
J/ApJ/640/1051 : 25pc sample of Sun-like stars (Grether+, 2006)
J/A+A/505/853 : HD16760 radial velocity curve (Bouchy+, 2009)
J/ApJ/710/1724 : Follow-up photometry for HAT-P-11 (Bakos+, 2010)
J/ApJ/720/1118 : i-band photometry of HAT-P-16 (Buchhave+, 2010)
J/other/Nat/486.375 : Stellar parameters of KOI stars (Buchhave+, 2012)
J/ApJ/756/L33 : RVs of 2 hot Jupiters in Praesepe (Quinn+, 2012)
J/ApJS/225/15 : IR excess stars from Tycho-2 and AllWISE (Cotten+, 2016)
J/AJ/153/136 : Planets & their host stars with Gaia parallaxes (Stassun+, 2017)
J/MNRAS/477/3406 : HATS-39b, 40b, 41b and 42b transit data (Bento+, 2018)
J/AJ/156/234 : KELT transit false positive catalog for TESS (Collins+, 2018)
J/AJ/156/102 : The TESS Input Catalog & Candidate Target List (Stassun+, 2018)
J/AJ/157/85 : The CIDA Variability Survey of Orion OB1. II. (Briceno+, 2019)
J/A+A/630/A89 : WASP-12b and WASP-43b griz light curves (Parviainen+, 2019)
J/AJ/159/255 : Obs. & radial velocity of WASP-150 & WASP-176 (Cooke+, 2020)
J/A+A/636/A98 : WASP-18A, WASP-19, WASP-77A photometry (Cortes-Zuleta+, 2020)
J/AN/341/996 : Stellar companions of (C)TOIs (Mugrauer+, 2020)
J/AJ/159/19 : SOAR TESS survey. I. (Ziegler+, 2020)
J/AJ/161/97 : Radial Velocities of TOI-811 and TOI-852 (Carmichael+, 2021)
J/A+A/652/A127 : 13-150MJ eclipsing binaries transiting comp. (Grieves+, 2021)
J/ApJS/254/39 : Exoplanet candidates from TESS first 2yr obs (Guerrero+, 2021)
J/AN/342/840 : Stellar companions of (C)TOIs (Mugrauer+, 2021)
J/ApJ/923/177 : TESS obs. & rot. periods of T Tauri in Orion (Serna+, 2021)
J/AJ/161/171 : THYME. V. Discovering a new stellar assoc. (Tofflemire+, 2021)
J/ApJS/259/33 : Faint-star TOIs from the TESS Primary Mission (Kunimoto+, 2022)
J/AJ/166/271 : FEROS spectra for 3 giants exoplanets (Eberhardt+, 2023)
J/AJ/165/268 : Radial velocity & rotation period of HIP 33069b (Vowell+, 2023)
J/ApJS/271/16 : Giant Outer Transiting Exoplanet Mass surv. IV. (Dalba+, 2024)
J/A+A/681/A55 : HD88986 radial velocity curves (Heidari+, 2024)
J/AJ/167/109 : TOI-1994 radial velocities with MINERVA & CHIRON (Page+, 2024)
J/MNRAS/528/5703 : 23 low mass stars photometry (Swayne+, 2024)
J/A+A/694/A36 : Velocity curves of 7 transiting systems (Heidari+, 2025)
Byte-by-byte Description of file: targets.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Target Target name
10- 19 F10.7 d Per Orbital period of planetary companion
(from Tables 6 & 7 of the paper)
21 A1 --- Flag [*] *=Bimodal models with high and low-mass
solutions (1)
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Note (1): Four of our fits resulted in bimodal posterior distributions. Here,
only the period from the higher-probability distribution solution is reported,
which is the low-mass solution for all four sources.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Target Target name
10- 23 F14.6 d BJD [2459395/2460500] Barycentric Julian Date in
Barycentric Dynamical Time
25- 33 F9.2 m/s RVel [-25093/20205] Radial velocity
35- 41 F7.2 m/s e_RVel [5.8/1791.21] Uncertainty in RV
43- 48 A6 --- Spec Spectrograph (1)
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Note (1): Spectrograph as follows:
SOPHIE = The Spectrographe pour l'Observation des Phenomenes des Interieurs
stellaires et des Exoplanetes (SOPHIE) installed on the 1.93m
reflector telescope at the Haute-Provence Observatory, France
(21 occurrences)
TRES = The Tillinghast Reflector Echelle Spectrograph (TRES) on the
1.5m Tillinghast optical telescope at the Fred L. Whipple
Observatory in Arizona, USA (139 occurrences)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Robin Leichtnam [CDS] 20-May-2026