J/AJ/169/76 Observed & derived parameters of TOI companions (Matson+, 2025)
Demographics of M Dwarf binary exoplanet hosts discovered by TESS.
Matson R.A., Gore R., Howell S.B., Ciardi D.R., Christiansen J.L.,
Clark C.A., Crossfield I.J.M., Fajardo-Acosta S.B., Fernandes R.B.,
Furlan E., Gilbert E.A., Gonzales E., Lester K.V., Lund M.B.,
Matthews E.C., Polanski A.S., Schlieder J.E., Ziegler C.
<Astron. J., 169, 76 (2025)>
=2025AJ....169...76M 2025AJ....169...76M
ADC_Keywords: Stars, double and multiple; Photometry, infrared; Exoplanets;
Stars, dwarfs; Stars, M-type; Optical
Keywords: Binary stars ; Exoplanet systems ; Low mass stars ; M dwarf stars
Abstract:
M dwarfs have become increasingly important in the detection of
exoplanets and the study of Earth-sized planets and their
habitability. However, 20%-30% of M dwarfs have companions that can
impact the formation and evolution of planetary systems. We use
high-resolution imaging and Gaia astrometry to detect stellar
companions around M dwarf exoplanet hosts discovered by TESS and
determine the projected separation and estimated stellar masses for
each system. We find 47 companions around 216 M dwarfs and a
multiplicity rate of 19.4±2.7% that is consistent with field M dwarfs.
The binary projected separation distribution is shifted to larger
separations, confirming the lack of close binaries hosting transiting
exoplanets seen in previous studies. We correct the radii of planets
with nearby companions and examine the properties of planets in
M dwarf multistar systems. We also note three multiplanet systems that
occur in close binaries (≤50AU) where planet formation is expected to
be suppressed.
Description:
TESS Objects of Interest (TOIs) with a stellar effective temperature
of 3900K or less in the TESS Input Catalog (TIC; IV/39) were selected
from the TESS Exoplanet Follow-up Observing Program (ExoFOP) website,
which resulted in a list of 308 potential M dwarf exoplanet host
stars. 65 of the TOIs have been classified as false positives (FPs),
9 as likely giants, and 13 as ambiguous planet candidates (APC), with
8 of them having already been identified as binary stars via
spectroscopy or the Gaia DR3 catalog of nonsingle stars
(Gaia Collab+2023, I/357). Our final sample therefore consists of a
total of 221 M dwarfs with confirmed or candidate transiting
exoplanets.
To assess the stellar multiplicity of these systems, we collected
high-resolution imaging observations of as many of the TOIs as
possible. We observed 148 of the M dwarf TOIs with speckle interferometry
between 2019 January-2024 January. Most of the observations were
obtained with the 'Alopeke and Zorro speckle imagers at the Gemini
8.1m North (Hawaii, US) and South (Chile) telescopes, respectively,
while some additional TOIs were observed using the NN-EXPLORE
Exoplanet Stellar Speckle Imager (NESSI) at the 3.5m WIYN telescope in
Arizona, US. Each speckle observation consists of one or more sets,
depending on the magnitude of the target star, of 1000x60ms exposures
taken in filters centered at 562nm (Δλ=54nm) and 832nm
(Δλ=40nm) simultaneously.
We also observed 85 M dwarf TOIs with near-infrared (NIR) AO imaging
using the Near-infrared Camera, Second Generation (NIRC2) on the Keck
II 10m telescope in Hawaii, US, and the Palomar High Angular
Resolution Observer (PHARO) on the 200inch Hale telescope at Palomar
Observatory in California, US, from 2018 November to 2022 August.
For NIRC2, both narrow (e.g., Brγ and Jcont) and broadband
filters (e.g., K) with central wavelengths near 2.2um were used
depending on the NIR magnitude of the target and the observing
conditions. Palomar observations were made in the Brγ
(λ0=2.1686um; Δ{;ambda}=0.0326um) and/or Hcont
(λ0=1.668um; Δλ=0.018um) filter depending on the
magnitude of the target, observing conditions, and whether a companion
was detected.
To augment our observations we inspected the additional
high-resolution imaging data available on the TESS Exoplanet Follow-up
Observing Program (ExoFOP) website. A majority of the observations
retrieved from ExoFOP, including 10 companion detections, were made
with the High-Resolution Camera (HRCam), a speckle imager on the
Southern Astrophysical Research (SOAR) 4.1m telescope in Chile.
Observations consist of two sets of 400 frames taken in the I-band
(λ0=824nm; Δλ=170nm) with a 6.3" field of view.
Additional speckle observations, including the detection of one
companion, were made by the Speckle Polarimeter on the 2.5m at the
Caucasian Observatory of the Sternberg Astronomical Institute of
Lomonosov Moscow State University in Ukraine. For each target 4000
frames with 30ms exposure times were obtained in the Ic filter
(λ0=806nm).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 47 308 M star TOIs with TIC and Gaia DR3 designations
table2.dat 69 52 Companions observed with high-resolution imaging
table3.dat 82 76 Companions detected using proper motions and
parallaxes
table4.dat 66 47 Observed and derived properties of the analyzed
companions
--------------------------------------------------------------------------------
See also:
B/wds : The Washington Visual Double Star Catalog (Mason+ 2001-2020)
IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)
IV/39 : TESS Input Catalog version 8.2 (TIC v8.2) (Paegert+, 2021)
I/357 : Gaia DR3 Part 3. Non-single stars (Gaia Collaboration, 2022)
J/A+A/450/68 : Companions to close spectroscopic binaries (Tokovinin+, 2006)
J/AJ/139/2566 : SLoWPoKES catalog (Dhital+, 2010)
J/ApJS/190/1 : A survey of stellar families (Raghavan+, 2010)
J/AJ/141/45 : Speckle observations of HIP stars (Horch+, 2011)
J/AJ/142/19 : Speckle observations of KOI (Howell+, 2011)
J/ApJS/192/2 : A Bayesian search for binaries in Hipparcos (Shaya+, 2011)
J/ApJ/754/44 : The AstraLux Large M-dwarf Survey (Janson+ 2012)
J/ApJ/779/188 : Spectra of nearby late K and M Kepler stars (Mann+, 2013)
J/ApJS/208/9 : Intrinsic colors and temperatures of PMS stars (Pecaut+, 2013)
J/AJ/150/57 : SLoWPoKES-II catalog (Dhital+, 2015)
J/ApJ/807/45 : Potentially habitable planets orbit. M dwarfs (Dressing+, 2015)
J/ApJ/814/130 : Planet occurrence rates calculated for KOIs (Mulders+, 2015)
J/MNRAS/449/2618 : M-dwarfs in Multiples (MinMs) survey. I. (Ward-Duong+, 2015)
J/AJ/152/8 : Impact of stellar multiplicity on planetary syst.I. (Kraus+, 2016)
J/AJ/153/25 : Near-infrared observations of 84 KOI systems (Atkinson+, 2017)
J/AJ/153/71 : Kepler follow-up observation program. I. Imaging (Furlan+, 2017)
J/MNRAS/480/4884 : Gaia wide binaries (El-Badry+, 2018)
J/AJ/156/83 : Effect of stellar companions on planetary syst. (Ziegler+, 2018)
J/AJ/156/259 : Robo-AO detected close binaries in Gaia DR2 (Ziegler+, 2018)
J/AJ/157/211 : Unresolved binaries in TESS with speckle imaging (Matson+, 2019)
J/AJ/157/216 : Stell multiplicity rate of M dwarfs within 25pc (Winters+, 2019)
J/AJ/159/211 : Exoplanets parameters from Kepler and K2 (Cloutier+, 2020)
J/ApJS/247/66 : SUPERWIDE: wide binaries in Gaia & SUPERBLINK (Hartman+, 2020)
J/ApJ/902/107 : Spectroscopic binary multiplicity with Robo-AO (Laos+, 2020)
J/AN/341/996 : Stellar companions of (C)TOIs (Mugrauer+, 2020)
J/ApJ/891/58 : TIC star exposure times for JWST, LUVOIR and OST (Suissa+, 2020)
J/AJ/159/19 : SOAR TESS survey. I. (Ziegler+, 2020)
J/A+A/650/A190 : Wide companions to M and L subdwarfs (Gonzalez-Payo+, 2021)
J/ApJS/254/39 : Exoplanet candidates from TESS first 2yr obs (Guerrero+, 2021)
J/AJ/161/134 : Survey of stellar & planetary comp. within 25pc (Hirsch+, 2021)
J/AJ/161/164 : Observation of 186 TESS stars with NESSI (WYIN) (Howell+, 2021)
J/AJ/162/75 : Speckle obs. TESS exoplanet host stars. II. (Lester+, 2021)
J/AN/342/840 : Stellar companions of (C)TOIs (Mugrauer+, 2021)
J/A+A/650/A201 : 10 parsec sample in the Gaia era first update (Reyle+, 2021)
J/A+A/649/A3 : Gaia Early Data Release 3 photometric passbands (Riello+, 2021)
J/AJ/162/192 : SOAR TESS surv.II. Impact of stellar companions (Ziegler+, 2021)
J/AJ/163/160 : Properties of 170 TOI hosts and companions (Behmard+, 2022)
J/AJ/163/168 : Photometry and radial velocity of LTT 1445A (Winters+, 2022)
J/AN/343/24017 : Stellar companions of (C)TOIs (Mugrauer+, 2022)
J/AJ/165/265 : Properties of 363 M-dwarfs from TESS (Ment+, 2023)
J/AN/344/55 : Stellar companions of (C)TOIs (Mugrauer+, 2023)
J/AJ/167/56 : The POKEMON Speckle Survey of nearby M dwarfs.II. (Clark+, 2024)
J/AJ/167/174 : The POKEMON Speckle Surv. of Nearby M Dwarfs.III. (Clark+, 2024)
J/A+A/686/A232 : AstraLux-TESS planet candidates (Lillo-Box+, 2024)
J/MNRAS/527/3183 : (Sub)Stellar companions of exoplanet hosts (Michel+ 2024)
J/AJ/167/89 : Architectures of S* Transit. Planets in Binar.I. (Zhang+, 2024)
http://exofop.ipac.caltech.edu/tess/ : TESS Exoplanet Follow-up Observing
Program (ExoFOP) website
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- TOI [122/5139] TESS Object of Interest identifier
6- 14 I9 --- TIC [1133072/900715901] TESS Input Catalog (IV/39)
identifier
16- 38 A23 --- GaiaDR3 Gaia DR3 (I/355) identifier
40- 42 A3 --- Status Planet status (1)
44- 47 A4 --- Comp Detected companions (2)
--------------------------------------------------------------------------------
Note (1): If the TOI was identified as a false positive (FP) or ambiguous
planet candidate (APC) as of February 8, 2024 it is marked in the
Status column and excluded from our sample. Nine additional TOIs have
parameters consistent with giant stars, marked with a 'g' in the
Status column, and were also excluded.
Status as follows:
FP = False Positive (65 occurrences)
APC = Ambiguous Planet Candidate (13 occurrences)
g = Parameters consistent with giant star (9 occurrences)
Note (2): This column shows whether a stellar companion was identified through
high-resolution imaging (HR) or Gaia common proper motions (G).
Companions found with high-resolution imaging but not bound to the
TOI are marked as `U'. The column includes companions detected with
high-resolution imaging around TOIs removed from our sample, however,
not all such TOIs have been searched for companions.
Identifications as follows:
HR = High-resolution Imaging (35 occurrences)
G = Gaia common proper motion (37 occurrences)
U = High-resolution imaging but not bound to the TOI (5 occurrences)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- TOI [256/4889] TESS Object of Interest identifier
6 A1 --- Flag Additional information on the system (1)
8- 26 A19 --- Inst Instrument (2)
28- 34 A7 --- Filter Filter
36- 44 F9.4 arcsec Sep [0.04/4683] Angular separation
46- 51 F6.2 deg PosAng [0.36/356] Position angle
53- 58 F6.4 mag dMag [0/6.72] Magnitude difference (3)
60- 69 A10 "Y:M:D" Date Date of observation (UT)
--------------------------------------------------------------------------------
Note (1): Flag as follows:
a = Companion parameters on ExoFOP refer to the outer components of a triple
system. Here we show the companion parameters with respect to the
primary star. See Section 3.1 for details.
b = Unbound, see Section 3.3.
c = KOI-245, observed by Kraus+2016 (J/AJ/152/8), ExoFOP observations
extracted from Furlan+2017 (J/AJ/153/71).
Note (2): Instruments as follows:
NIRC2 = Near-infrared Camera, Second Generation (NIRC2), an
imager on the Keck II 10m telescope in Hawaii, US;
(6 occurrences)
PHARO = Palomar High Angular Resolution Observer (PHARO), a
NIR camera on the 200inch Hale telescope at Palomar
Observatory in California, US; (18 occurrences)
HRCam = High-Resolution Camera (HRCam), a speckle imager on the
Southern Astrophysical Research (SOAR) 4.1m telescope
in Chile; (13 occurrences)
Alopeke = a speckle imager at the Gemini 8.1m North telescope in
Hawaii, US; (5 occurrences)
Zorro = a speckle imagers at the Gemini 8.1m South telescope in
Chile; (8 occurrences)
NESSI = NN-EXPLORE Exoplanet Stellar Speckle Imager (NESSI), a
speckle imager at the 3.5m WIYN telescope in Arizona, US;
(1 occurrence)
Speckle Polarimeter = on the 2.5m at the Caucasian Observatory of the
Sternberg Astronomical Institute of Lomonosov Moscow
State University in Ukraine; (1 occurrence)
Note (3): Magnitude differences are measured in different filters for each
technique and have not been transformed to a common wavelength or
filter.
--------------------------------------------------------------------------------
Byte-by-byte Description of file:table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- TOI [218/4991] TESS Object of Interest identifier
6- 9 A4 --- Comp Companion flag (1)
11 A1 --- Flag Additional information on the system (2)
13- 18 F6.2 arcsec Sep [0.8/536.6]? Angular separation
20- 25 F6.2 deg PosAng [0.03/356.3]? Position angle
27- 30 F4.2 mag dMag [0.02/7.67]? Magnitude difference
32- 36 F5.2 mag Gmag [5.9/20.6] Gaia G-band magnitude
38- 42 F5.2 mas plx [2.2/44.6] Parallax
44- 47 F4.2 mas e_plx [0.01/2.6] Parallax uncertainty
49- 55 F7.2 mas/yr pmRA [-403.2/280.7] Proper motion in right
ascension
57- 60 F4.2 mas/yr e_pmRA [0.01/1.8] pmRA uncertainty
62- 68 F7.2 mas/yr pmDE [-381/191.3] Proper motion in declination
70- 73 F4.2 mas/yr e_pmDE [0.01/1.5] pmDE uncertainty
75- 82 A8 --- Ref References (3)
--------------------------------------------------------------------------------
Note (1): The companion flag is given for rows immediately subsequent to the
otherwise unflagged primary.
Note (2): Flag as follows:
a = Detected companion is brighter than the TOI.
b = Companion also detected with high-resolution imaging.
Note (3): References as follows:
E21 = El-Badry+ (2021MNRAS.506.2269E 2021MNRAS.506.2269E); 28 occurrences
M20 = Mugrauer+2020 (J/AN/341/996); 14 occurrences
M21 = Mugrauer+2021 (J/AN/342/840); 8 occurrences
M22 = Mugrauer+2022 (J/AN/343/24017); 1 occurrence
M23 = Mugrauer+2023 (J/AN/344/55); 4 occurrence
--------------------------------------------------------------------------------
Byte-by-byte Description of file:table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- TOI [218/4991] TESS Object of Interest identifier
6 A1 --- Flag Flag to indicate that the TOI is fainter than
the detected companion and assumed to be the
secondary
8- 14 F7.2 arcsec Sep [0.04/4682.2] Angular separation
16- 20 F5.2 mag mag1 [5.1/16.2] Estimated apparent magnitude of
the primary
22 A1 --- Filt Filter (1)
24- 28 F5.2 mag mag2 [7.2/20.7] Estimated apparent magnitude of
the secondary
30- 33 I4 K Teff [3022/3896] Effective temperature
35- 40 F6.2 pc Dist [6.8/415] Distance
42- 49 F8.2 AU SepProj [1.6/97538] Projected physical separation
51- 54 F4.2 Msun Mass1 [0.16/0.57] Mass of the primary
56- 60 F5.3 Msun Mass2 [0.08/0.54] Mass of the secondary
62- 66 F5.2 --- RUWE [0.93/13.8] Gaia DR3 (I/355) renormalized
unit weight error
--------------------------------------------------------------------------------
Note (1): Filters as follows:
G = Gaia G-band (30 occurrences)
I = I-band (9 occurrences)
K = K-band (8 occurrences)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Robin Leichtnam [CDS] 19-Nov-2025