J/AJ/165/269 TW Hya association candidate members (Luhman, 2023)
A Census of the TW Hya Association with Gaia.
Luhman K.L.
<Astron. J., 165, 269 (2023)>
=2023AJ....165..269L 2023AJ....165..269L
ADC_Keywords: Associations, stellar; Spectra, optical; Photometry, infrared;
Spectral types; Proper motions; Parallaxes, trigonometric
Keywords: Star formation ; Initial mass function ; Low mass stars ;
Stellar associations ; Circumstellar disks ; Protoplanetary disks
Abstract:
I have used high-precision photometry and astrometry from the third
data release of Gaia to perform a survey for members of the TW Hya
association (TWA). I have identified candidate members that appear to
share similar kinematics and ages with bona fide members compiled by
Gagne et al. (2017), and I have assessed their membership using radial
velocities and spectroscopic diagnostics of age from various sources.
My new catalog of adopted members contains 67 Gaia sources in 55
systems. The histogram of spectral types for TWA peaks near M5
(∼0.15M☉), resembling the distributions measured for other nearby
young associations. The UVW velocities of its members indicate that
the association is expanding. The rate of expansion corresponds to an
age of 9.6-0.8+0.9Myr. In a Gaia color-magnitude diagram, the
members of TWA exhibit well-defined sequences of single stars and
unresolved binary stars. The combined sequence of low-mass stars in
TWA is indicative of an age of 11.4-1.2+1.3Myr when compared to
the sequence for Upper Centaurus Lupus/Lower Centaurus Crux, for which
an age of 20Myr is assumed. Based on these expansion and isochronal
ages, I have adopted an age of 10±2Myr for TWA. Finally, I have
used mid-infrared photometry from the Wide-field Infrared Survey
Explorer to check for excess emission from circumstellar disks among
the TWA members. Fourteen members have detected disks, all of which
have been reported in previous studies. The fraction of members at
≲M6≳0.1M☉) that have full, transitional, or evolved disks is
10/52=0.19-0.06+0.08. That value is similar to the fraction
previously measured for the Upper Sco association, which is roughly
coeval with TWA.
Description:
I have compiled previous measurements of radial velocities for the
bona fide members of TW Hya association (TWA) and the additional
candidate members. For most stars that have multiple radial velocity
measurements, I have adopted the velocity with the smallest error.
For candidate members of TWA that lack spectral classifications from
previous studies, I have searched for spectra in the data archives of
various observatories. I found optical spectra of five candidates that
were obtained with the Fiber-fed Optical Echelle Spectrograph (FEROS)
on the Max-Planck-Gesellschaft/European Southern Observatory 2.2m
telescope through program 090.C-0200(A), the Gemini Multi-Object
Spectrograph (GMOS) at the Gemini South telescope through program
GS-2014A-Q-44, and the Ultraviolet and Visual Echelle Spectrograph
(UVES) on the Unit Telescope 2 of the Very Large Telescope through
program 092.C-0203(A). All of the spectra in question cover a wide
range of wavelengths, spanning from 6000 to 9000Å at a minimum. The
data from GMOS, UVES, and FEROS exhibit R∼4400, 20000, and 48000,
respectively.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 50 13 New spectral classifications for candidate members
of TWA
table2.dat 502 67 Adopted Members of TWA
fig3_1.dat 24 3826 GMOS spectrum of Gaia DR3 3493814268751183744
fig3_2.dat 24 3826 GMOS spectrum of Gaia DR3 5348165127505382400
fig3_3.dat 24 3826 GMOS spectrum of Gaia DR3 5401389770971149568
fig3_4.dat 24 3826 GMOS spectrum of Gaia DR3 6114656192408518784
fig3_5.dat 24 3826 GMOS spectrum of Gaia DR3 6143632653128880896
fig3_6.dat 24 3826 GMOS spectrum of Gaia DR3 6143984423832713856
fig3_7.dat 24 3826 GMOS spectrum of Gaia DR3 6143984428129994624
fig3_8.dat 24 6227 GMOS spectrum of Gaia DR3 6145303429765430784
fig3_9.dat 24 3826 GMOS spectrum of Gaia DR3 6179256348830614784
refs.dat 71 51 References used
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See also:
III/135 : Henry Draper Catalogue and Extension (Cannon+ 1918-1924; ADC 1989)
II/328 : AllWISE Data Release (Cutri+ 2013)
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
I/352 : Distances to 1.47 billion stars in Gaia EDR3 (Bailer-Jones+, 2021)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/ApJS/99/135 : Rotation and Spectral Peculiarities (Abt+ 1995)
J/ApJ/525/466 : Young low-mass stars & brown dwarfs in IC348 (Luhman+, 1999)
J/other/ARA+A/42.685 : Young stars near the Sun (Zuckerman+, 2004)
J/ApJ/620/1010 : Spitzer 24µm photometry of A dwarfs (Rieke+, 2005)
J/AJ/132/866 : New M dwarfs in solar neighborhood (Riaz+, 2006)
J/A+A/460/695 : Search Associations Containing Young stars (Torres+, 2006)
J/ApJ/662/1067 : Sptizer observations of sigma Orionis (Hernandez+, 2007)
J/AJ/136/1290 : Ultracool dwarfs from the 2MASS (Reid+, 2008)
J/ApJS/186/111 : Spitzer observations of Taurus members (Luhman+, 2010)
J/A+A/517/A76 : Near-IR spectrum of 2M1207b (Patience+, 2010)
J/ApJ/758/31 : IR photometry for members of Upper Sco (Luhman+, 2012)
J/A+A/551/A107 : Xshooter spectra of 24 young stellar objects (Manara+, 2013)
J/ApJS/208/9 : Intrinsic colors & temperatures of PMS stars (Pecaut+, 2013)
J/A+A/562/A127 : NIR integral field spectra of 15 M-Ldwarfs (Bonnefoy+, 2014)
J/A+A/568/A26 : SACY. V. Multiple systems (Elliott+, 2014)
J/ApJ/784/126 : IR photometry of all known members in Taurus (Esplin+, 2014)
J/ApJ/786/97 : Photospheric properties of T Tauri stars (Herczeg+, 2014)
J/ApJ/788/81 : BANYAN III. RVel & rotation of low-mass stars (Malo+, 2014)
J/A+A/564/A55 : 1.1-2.4um spectra of 7 young M & Ldwarfs (Manjavacas+, 2014)
J/AJ/147/85 : Solar neighborhood. XXXIII. 45 M dwarfs (Riedel+, 2014)
J/MNRAS/454/593 : Young moving groups in solar neighbourhood (Bell+, 2015)
J/ApJS/219/33 : BANYAN. VII. Candidate YMG members from BASS (Gagne+, 2015)
J/MNRAS/453/2220 : Early-type Sco-Cen memb with literature RVs (Murphy+, 2015)
J/AJ/154/134 : Planetary-mass brown dwarfs in Taurus SFR (Esplin+, 2017)
J/AJ/153/46 : Spectroscopy of candidate members in Taurus (Luhman+, 2017)
J/ApJ/840/87 : Young star systems observed with SALT (Riedel+, 2017)
J/AJ/154/69 : ACRONYM II. β Pictoris Moving Group (Shkolnik+, 2017)
J/ApJS/234/1 : M, L, & T dwarfs from PS1 3π Survey (Best+, 2018)
J/MNRAS/478/4513 : GALAH Survey DR2 (Buder+, 2018)
J/AJ/156/75 : Circumstellar disks in Upper Sco association (Esplin+, 2018)
J/MNRAS/475/1960 : ESPaDOnS spectropolarimeter obs. of M dwarfs (Fouque+, 2018)
J/ApJ/862/138 : BANYAN. XIII. Nearby young assoc. Gaia DR2 (Gagne+, 2018)
J/ApJ/856/23 : BANYAN. XI. The BANYAN Σ algorithm (Gagne+, 2018)
J/ApJ/877/60 : YMGs. I. Young binaries & lithium-rich stars (Bowler+, 2019)
J/MNRAS/489/3625 : Applying Chronostar βPictoris group (Crundall+, 2019)
J/AJ/157/234 : ACRONYM. III. Cand young low-mass stars (Schneider+, 2019)
J/A+A/632/A46 : TW Hydrae association with X-shooter (Venuti+, 2019)
J/AJ/159/257 : Hawaii IR plx program IV. L0-T8 BDs with UKIRT (Best+, 2020)
J/MNRAS/491/215 : Supplementary data for 146 cand young stars (Binks+, 2020)
J/AJ/160/44 : Upper Scorpius spectroscopy and photometry (Luhman+, 2020)
J/A+A/642/A179 : betaPictoris moving group RV of 81 stars (Miret-Roig+, 2020)
J/A+A/649/A3 : Gaia EDR3 photometric passbands (Riello+, 2021)
J/A+A/645/A30 : SB updated census in SACY sample (Zuniga-Fernandez+, 2021)
J/AJ/163/24 : Stellar populations in the Sco-Cen complex (Luhman, 2022)
J/AJ/163/25 : Circumstellar disk pops in Sco-Cen complex (Luhman, 2022)
J/MNRAS/520/6245 : Dynamical age Tucana-Horologium (Galli+, 2023)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- Gaia Gaia DR3 source identifier
21- 25 A5 --- SpT New spectral type
27 A1 --- l_lambda [<] Limit on lambda
29- 32 F4.2 0.1nm lambda [0.1/0.8]? Wavelength Wλ(Li) (Å) (1)
34- 38 A5 --- Inst Instrument used (FEROS or GMOS)
40- 43 I4 yr Obs.Y [2013/2023] Year of observation
45- 47 A3 "month" Obs.M Month of observation
49- 50 I2 d Obs.D Day of observation
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Note (1): Uncertainties are 0.05Å
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- Gaia Gaia DR3 source name
21- 47 A27 --- Name Other source name
49- 58 F10.6 deg RAdeg [146/210] Gaia DR3 right ascension
(ICRS at Epoch 2016.0)
60- 69 F10.6 deg DEdeg [-53/-17] Gaia DR3 declination
(ICRS at Epoch 2016.0)
71-107 A37 --- SpT Spectral type
109-137 A29 --- r_SpT Spectral type reference
139-143 A5 --- Adopt Adopted spectral type
145-152 F8.3 mas/yr pmRA [-119/-38]? Gaia DR3 proper motion in right
ascension
154-158 F5.3 mas/yr e_pmRA [0.01/0.7]? Error in pmRA
160-166 F7.3 mas/yr pmDE [-42/10]? Gaia DR3 proper motion in
declination
168-172 F5.3 mas/yr e_pmDE [0.01/0.7]? Error in pmDec
174-179 F6.3 mas plx [9.5/29.4]? Gaia DR3 parallax
181-185 F5.3 mas e_plx [0.01/1]? Error in plx
187-193 F7.3 pc rmedgeo [34/105]? Median of geometric distance
posterior (1)
195-201 F7.3 pc rlogeo [34/105]? 16th percentile of geometric
distance posterior (1)
203-209 F7.3 pc rhigeo [34/105]? 84th percentile of geometric
distance posterior (1)
211-216 F6.3 km/s RVel [3.79/20]? Radial velocity
218-222 F5.3 km/s e_RVel [0.01/7]? Error in RVel
224-225 I2 --- r_RVel [1/18]? Radial velocity reference (2)
227-232 F6.2 km/s U [-14.8/-6.19]? U component of space velocity
234-237 F4.2 km/s e_U [0.01/2.97]? Error in U
239-244 F6.2 km/s V [-28.4/-13.7]? V component of space velocity
246-249 F4.2 km/s e_V [0.01/6.05]? Error in V
251-256 F6.2 km/s W [-11.3/-0.37]? W component of space velocity
258-261 F4.2 km/s e_W [0.01/2.91]? Error in W
263-268 F6.3 mag Gmag [5.42/20.6] Gaia DR3 G magnitude
270-274 F5.3 mag e_Gmag [0.003/0.07] Error in Gmag
276-281 F6.3 mag GBPmag [5.44/21.7]? Gaia DR3 GBP magnitude
283-287 F5.3 mag e_GBPmag [0.003/0.3]? Error in GBPmag
289-294 F6.3 mag GRPmag [5.35/19]? Gaia DR3 GRP magnitude
296-300 F5.3 mag e_GRPmag [0.004/0.3]? Error in GRPmag
302-307 F6.3 --- RUWE [0.87/10.5]? Gaia DR3 renormalized unit
weight error
309-331 A23 --- 2M Closest 2MASS source within 3 arcsec
333-336 F4.2 arcsec 2Msep [0.01/2]? Angular separation between
Gaia DR3 (epoch 2000) and 2MASS
338-338 A1 --- 2Mclose Is this Gaia source the closest match for
the 2MASS source?
340-364 A25 --- wise Closest WISE source within 3 arcsec
366-369 F4.2 arcsec wisesep [0/1.85]? Angular separation between Gaia DR3
(epoch 2010.5) and WISE
371-371 A1 --- wiseclose Is this Gaia source the closest match for
the WISE source?
373-378 F6.3 mag Jmag [5.313/15.494]? 2MASS J magnitude
380-384 F5.3 mag e_Jmag [0.018/0.058]? Error in Jmag
386-391 F6.3 mag Hmag [5.352/14.608]? 2MASS H magnitude
393-397 F5.3 mag e_Hmag [0.022/0.067]? Error in Hmag
399-404 F6.3 mag Ksmag [5.235/14.04]? 2MASS Ks magnitude
406-410 F5.3 mag e_Ksmag [0.017/0.06]? Error in Ksmag
412-417 F6.3 mag W1mag [5.212/13.64]? WISE W1 magnitude
419-423 F5.3 mag e_W1mag [0.022/0.079]? Error in W1mag
425-430 F6.3 mag W2mag [4.996/13.204]? WISE W2 magnitude
432-436 F5.3 mag e_W2mag [0.019/0.054]? Error in W2mag
438-442 A5 --- f_W2mag Flag on W2mag (3)
444-449 F6.3 mag W3mag [3.11/11.785]? WISE W3 magnitude
451-455 F5.3 mag e_W3mag [0.013/0.212]? Error in W3mag
457-461 A5 --- f_W3mag Flag on W3mag (3)
463-467 F5.3 mag W4mag [0.202/8.853]? WISE W4 magnitude
469-473 F5.3 mag e_W4mag [0.009/0.404]? Error in W4mag
475-479 A5 --- f_W4mag Flag on W4mag (3)
481-481 A1 --- ExcW2 ? Excess present in W2?
483-483 A1 --- ExcW3 ? Excess present in W3?
485-485 A1 --- ExcW4 ? Excess present in W4?
487-498 A12 --- DiskType ? Disk Type (4)
500-500 A1 --- bfmem Bona fide member of TWA (Gagne et al. 2017)
502-502 A1 --- outlier Spatial outlier
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Note (1): Bailer-Jones+, 2021, I/352
Note (2): References as follows:
1 = Schneider+, 2019, J/AJ/157/234
2 = Gaia DR3
3 = Buder+, 2018, J/MNRAS/478/4513
4 = Gagne+, 2017ApJS..228...18G 2017ApJS..228...18G
5 = Bailey+, 2012ApJ...749...16B 2012ApJ...749...16B
6 = Murphy+, 2015, J/MNRAS/453/2220
7 = Fouque+, 2018, J/MNRAS/475/1960
8 = Zuniga-Fernandez+, 2021A&A...645..A30Z
9 = Shkolnik+, 2011ApJ...727....6S 2011ApJ...727....6S
10 = Zuniga-Fernandez+, 2021A&A...655..A15Z
11 = Torres+, 2003AJ....125..825T 2003AJ....125..825T
12 = Mohanty+, 2003ApJ...593LL109M
13 = Looper+, 2010AJ....140.1486L 2010AJ....140.1486L
14 = Looper+, 2010ApJ...714...45L 2010ApJ...714...45L
15 = Venuti+, 2019A&A...632..A46V
16 = Reid, 2003MNRAS.342..837R 2003MNRAS.342..837R
17 = Elliott+, 2014A&A...568..A26E
18 = Kidder+, 2019ApJ...879...63K 2019ApJ...879...63K
Note (3): Flag as follows:
nodet = nondetection;
false = detection from WISE catalog appears to be false or
unreliable based on visual inspection.
Note (4): Excess classifications in W4 for TWA 8B and TWA 26 are based on
24 micron photometry from the Spitzer Space Telescope
(Luhman+, 2010, J/ApJS/186/L111)
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Byte-by-byte Description of file: fig3_[123456789].dat
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Bytes Format Units Label Explanations
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1- 11 F11.6 0.1nm lambda Wavelength (Å)
13- 24 E12.5 --- F7500 Flux ratio (Fλ/F7500Å)
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref [1/51] Reference code
4- 24 A21 --- Author Main author (et al.)
26- 44 A19 --- BIB BIBcode
46- 61 A16 --- Cat. Catalog in VizieR
63- 71 A9 --- Note Additional note
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 27-Oct-2023