J/ApJ/952/68 A search for stellar siblings of TOI-251b syst. (Sun+, 2023)
A search for stellar siblings of the ∼200Myr TOI-251b planetary system.
Sun Q., Wang S.X., Mann A.W., Tofflemire B.M., Kraus A.L., Gan T.,
Barber M.G.
<Astrophys. J., 952, 68 (2023)>
=2023ApJ...952...68S 2023ApJ...952...68S
ADC_Keywords: Exoplanets; Associations, stellar; Colors; Photometry; Optical;
Radial velocities; Stars, ages; Ultraviolet; Infrared
Keywords: Stellar associations ; Exoplanet evolution ; Early stellar evolution ;
Stellar dynamics ; Stellar ages ; Stellar rotation
Abstract:
Young planets (<1Gyr) are helpful for studying the physical processes
occurring at the early stage of planet evolution. TOI-251 b is a
recently discovered sub-Neptune orbiting a young G dwarf, which has an
imprecise age estimation of 40-320Myr. We select TOI-251 sibling
candidates based on kinematics and spatial proximity to TOI-251 and
further use the color-magnitude diagram to refine the list and to
compare to multiple open clusters. We report the stellar rotational
period for 321 sibling candidates in a 50pc radius around TOI-251 by
analyzing their stellar light curves and find a color-rotational
period sequence that lies in between the Group X (300Myr) and Pleiades
(120Myr) members, suggesting an age ∼200Myr. A quantitative age
analysis using gyrochronology relations gives 204±45Myr, consistent
with the average Li age of selected siblings (238±38Myr) and the
Gaia variability age (193-54102Myr). The detection fraction of
comoving candidates that have a short rotational period is 68.1%, much
higher than the typical value in the field (14%-16% from Kepler). The
overdensity of young stars and consistency in age of stellar siblings
suggest a potential young association candidate in the Phoenix-Grus
constellation. Though TOI-251 b has a radius larger than most of its
field-age counterparts, we are uncertain whether TOI-251 is inflated,
due to a lack of knowledge on the planet's mass.
Objects:
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RA (ICRS) DE Designation(s)
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23 32 14.83 -37 15 21.1 TOI-251 = CD-37 15287
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 196 321 Parameters for TOI-251 sibling candidates
table2.dat 90 30 Siblingship and gyrochronology age for TOI-251
comoving candidates
table3.dat 77 6 EW and age posterior for selected candidates
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See also:
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
II/328 : AllWISE Data Release (Cutri+ 2013)
II/335 : Revised cat. of GALEX UV sources (GUVcat_AIS GR6+7) (Bianchi+ 2017)
IV/34 : K2 Ecliptic Plane Input Catalog (EPIC) (Huber+, 2017)
IV/39 : TESS Input Catalog version 8.2 (TIC v8.2) (Paegert+, 2021)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
J/A+A/331/81 : Hyades membership (Perryman+ 1998)
J/ApJ/687/1264 : Age estimation for solar-type dwarfs (Mamajek+, 2008)
J/ApJ/695/679 : Stellar rotation in M35 (Meibom+, 2009)
J/ApJ/733/115 : Rotation periods and membership in M34 (Meibom+, 2011)
J/MNRAS/416/3108 : Membership of Sco OB2 moving group (Rizzuto+, 2011)
J/ApJ/756/L33 : Rvel of 2 hot Jupiters in Praesepe (Quinn+, 2012)
J/ApJS/208/9 : Intrinsic colors & temperatures of PMS stars (Pecaut+, 2013)
J/AJ/147/146 : Spectroscopy of Tuc-Hor candidate members (Kraus+, 2014)
J/ApJS/211/24 : Rotation periods of Kepler MS stars (McQuillan+, 2014)
J/A+A/588/A103 : 2nd ROSAT all-sky survey (2RXS) source cat. (Boller+, 2016)
J/AJ/152/113 : Pleiades members with K2 LCs. I. Periods (Rebull+, 2016)
J/AJ/153/128 : WOCS. LXXV. Hyades&Praesepe lithium data (Cummings+, 2017)
J/AJ/156/37 : Li abund. of cool dwarfs in M35 (Anthony-Twarog+, 2018)
J/ApJ/855/115 : Lithium abundances of KOIs from CKS spectra (Berger+, 2018)
J/A+A/613/A63 : Lithium content for 148 Pleiades stars (Bouvier+, 2018)
J/A+A/618/A93 : Gaia DR2 open clusters in the MW (Cantat-Gaudin+, 2018)
J/ApJ/856/23 : BANYAN. XI. The BANYAN Σ algorithm (Gagne+, 2018)
J/AJ/156/102 : TESS Input Catalog & Candidate Target List (Stassun+, 2018)
J/ApJ/879/100 : K2 rot. periods for Hyades & Praesepe (Douglas+, 2019)
J/A+A/633/A53 : TESS planet candidates classification (Osborn+, 2020)
J/AJ/160/239 : Cluster difference imaging phot. survey. II. (Bouma+, 2020)
J/ApJ/898/27 : Ages For Field LowEr-mass Stars (Stanford-Moore+, 2020)
J/AJ/159/19 : SOAR TESS survey. I. (Ziegler+, 2020)
J/AJ/159/220 : WOCS LXXIX. M48. I. WIYN/Hydra sp. for M48 (Sun+, 2020)
J/ApJS/250/20 : Rotation periods in TOIs (Canto+, 2020)
J/MNRAS/500/1158 : Rotation & lithium depletion of M35 dwarfs (Jeffries+, 2021)
J/ApJ/917/23 : SPYGLASS. I. Mapping young stellar structures (Kerr+, 2021)
J/AJ/161/65 : THYME. IV. 3 Exoplanets around TOI-451 B (Newton+, 2021)
J/ApJS/254/39 : Exoplanets from TESS first 2yr obs (Guerrero+, 2021)
J/ApJS/255/17 : Rotation & activity for Kepler stars. II. (Santos+, 2021)
J/AJ/161/171 : THYME. V. A new stellar assoc. (Tofflemire+, 2021)
J/A+A/661/A23 : Exoplanet X-ray irradiation & evaporation (Foster+, 2022)
J/AJ/164/88 : THYME. VIII. MELANGE-3 candidate members (Barber+, 2022)
J/AJ/163/121 : Radial velocity & light curve of Kepler 1627A (Bouma+, 2022)
J/AJ/163/228 : Limb-darkening coeff. of TESS exoplanets (Patel+, 2022)
J/AJ/164/215 : Candidate members of Cep-Her, RSG-5 and CH-2 (Bouma+, 2022)
J/ApJS/260/8 : 541 new open cluster candidates (He+, 2022)
J/ApJS/259/33 : Faint-star TOIs from TESS Primary Mission (Kunimoto+, 2022)
J/AJ/163/156 : THYME. VI. TOI-1227 radial velocity (Mann+, 2022)
J/AJ/164/115 : TESS Hunt for Young and Maturing Exopl. VII. (Newton+, 2022)
J/AJ/168/177 : Detecting exoplanet transits: X-ray data (Cilley+, 2024)
J/A+A/699/A100 : Exoplanets & host stars Gaia spect. cat. (de Laverny+, 2025)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- Gaia Gaia DR3 identifier
21- 30 I10 --- TIC [2733583/2056038856] TESS Input Catalog
identifier
32- 42 F11.7 deg RAdeg Right Ascension (ICRS) at Epoch=2016.0
44- 54 F11.7 deg DEdeg [-65/-8.8] Declination (ICRS) at Epoch=2016.0
56- 61 F6.3 mag Gmag [3.7/19.5] Gaia DR3 G-band magnitude
63- 68 F6.3 mag Rpmag [2.7/18]? Gaia DR3 RP-band magnitude
70- 75 F6.3 mag BP-RP [-0.08/4.2]? Gaia DR3 BP-RP color
77- 81 F5.3 mag BP/RP [1/2.8]? Gaia DR3 BP/RP flux excess
83- 87 F5.3 km/s Voff [0/5] Tangential velocity offset
89- 95 F7.4 deg Sep [0/29.5] Spatial separation to TOI-251
97- 103 F7.4 pc SepProj [0/50] (3D) projected separation to TOI-251
105- 110 F6.2 km/s RVelpre [-12.2/8.1] Predicted radial velocity
112- 116 F5.2 km/s RVelobs [-6.3/3.4]? Gaia DR3 observed radial velocity
118- 122 F5.2 km/s e_RVelobs [0.14/25.2]? Uncertainty in RVel-obs
124- 127 F4.2 km/s Vtot [0/6.5]? Total velocity offset
129- 134 F6.3 mas plx [6.7/17] Gaia DR3 parallax
136- 139 A4 --- SpT Gaia DR3 Spectral Type (1)
141- 148 F8.6 --- FnuvJ [5e-06/0.023]? GALEX (II/335) Flux ratio,
FNUV/FJ (https://doi.org/10.26131/irsa166)
150- 155 F6.3 mag W1-W3 [-0.22/1]? ALLWISE (II/311) W1-W3 color
(https://doi.org/10.26131/irsa1)
157- 161 F5.3 --- RUWE [0.78/9.6] Gaia DR3 renormalized unit weight
error
163- 167 F5.2 d Prot [1/13.8]? Derived stellar rotational period
169- 173 F5.2 d e_Prot [0.06/1.7]? Uncertainty in Prot
175- 190 A16 --- Comm Comments (2)
192- 196 A5 --- Sib Siblingship (3)
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Note (1): Spectral type is calculated based on Gaia DR3 color
(2023A&A...674A..32B 2023A&A...674A..32B, https://doi.org/10.26131/irsa544) and the
location in the color-magnitude diagram.
Note (2): Comments on whether light curve is available for the given
star ("no lc") and whether short-period rotational signal is
detected ("non-detection"). Four additional sources are flagged
as "likely pulsation" based on their blue BP-RP colors.
Note (3): The candidates that are rejected based on Prot or Li-age
are identified in column "Sib" by using a superscript of "Li" or
"P" right to "N".
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 1 I1 --- grp [1/2] Subset (1)
3- 11 I9 --- TIC [5774692/616064178] TESS Input Catalog identifier
14- 14 A1 --- flags Source flags (2)
17- 22 F6.3 mag Gmag [8/15.2] Gaia DR3 G band magnitude
24- 28 F5.3 mag BP-RP [0.4/2.9] Gaia DR3 BP-RP color
30- 34 F5.3 km/s Voff [0/5] Tangential velocity offset
36- 40 F5.2 km/s RVel [-6.3/3.1] Radial Velocity
42- 46 F5.3 --- RUWE [0.78/9] Gaia DR3 renormalized unit weight error
48- 52 F5.3 mag B-V0 [0.27/1.81]? TIC dereddened B-V color (3)
54- 58 F5.3 mag e_B-V0 [0.029/0.35]? Uncertainty in B-V0 (3)
60- 63 F4.2 d Prot [1.69/9.3]? Derived stellar rotational period
66- 66 A1 --- f_Prot Flag on Prot (4)
69- 72 F4.2 d e_Prot [0.06/1.4]? Uncertainty in Prot
74- 76 I3 Myr Age1 [106/757]? Age, Mamajek & Hillenbrand (2008) (5)
78- 80 I3 Myr e_Age1 [34/521]? Uncertainty in Age1 (5)
82- 84 I3 Myr Age2 [83/865]? Age, Meibom et al. (2009) (5)
86- 88 I3 Myr e_Age2 [31/883]? Uncertainty in Age2 (5)
90- 90 A1 --- Sib [NUY] Siblingship (Y=sibling; U=Uncertain; or
N=non-sibling)
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Note (1): Table subset as follows:
1 = All comoving candidates in 0.4<BP-RP<1.3;
2 = Siblings in BP-RP>1.3.
Note (2): Source flags as follows:
4 = The first line is TOI-251;
5 = The final siblingship designation has been changed to "N"
after checking its Li age.
Note (3): De-reddened (B-V)0 computed based on B, V , and B-V color
excess from the TESS Input Catalog. Errors are propagated from B,
V , and B-V.
Note (4): For candidates bluer than 0.5 mag, the reported PROT are
likely not real but pulsations.
Note (5): Age in Myr based on gyrochronology relations from
Mamajek & Hillenbrand (2008, J/ApJ/687/1264, Age1) and
Meibom+ (2009, J/ApJ/695/679, Age2). Ages are set to null values
if the gyrochronology relation is not applicable. Errors
are propagated from period and (B-V)0 (e_Age1, e_Age2).
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Simbad SIMBAD name
13- 19 A7 --- OName Other name
21- 29 I9 --- TIC [12434574/224225541] TESS Input Cat.
identifier (1)
31- 35 F5.3 mag BP-RP [0.13/0.98] Gaia DR3 BP-RP color
37- 41 F5.3 mag B-V0 [0.08/0.85] TIC dereddened B-V color
43- 43 A1 --- MmProt [NUY] Membership based on rotational period
45- 47 I3 0.1pm EWLi [6/139] Lithium equivalent width, mÅ (2)
49- 49 A1 --- f_EWLi [*] *=treat EWLi<10mA as upper limit (1)
51- 53 I3 Myr Age [210/437]? Age from BAFFLE posterior
55- 59 F5.1 Myr AgeR1lo [53.9/331]? 1 σ Age range, lower bound
61- 63 I3 Myr AgeR1up [441/596]? 1 σ Age range, upper bound
65- 69 F5.1 Myr AgeR2lo [13/168]? 2 σ Age range, lower bound
71- 73 I3 Myr AgeR2up [577/763]? 2 σ Age range, upper bound
75- 75 A1 --- SibLi [NUY] Association member based on its Li age
77- 77 A1 --- f_SibLi Final membership for HD 798 uncertain (3)
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Note (1): TIC 144276313 (the star with the bluest Bp-Rp color) has a Li EW
measurement of only 6mÅ, and we recommend that readers treat this
as an upper limit. Furthermore, no cluster data lie in this color
range, so we exclude TIC 144276313 from further discussions regarding
the age of the association.
Note (2): Lithium equivalent width includes the contribution from the
FeI 6707.4Å line.
Note (3): The final membership designation for HD 798 is uncertain
because its Prot pattern suggests uncertain membership.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 27-Aug-2025