J/AJ/156/271 The stellar membership of the Taurus SFR (Luhman, 2018)
The stellar membership of the Taurus star-forming region.
Luhman K.L.
<Astron. J., 156, 271-271 (2018)>
=2018AJ....156..271L 2018AJ....156..271L (SIMBAD/NED BibCode)
ADC_Keywords: Star Forming Region ; Populations, stellar ; Spectral types ;
Proper motions ; Parallaxes, trigonometric ; Radial velocities ;
Space velocities ; Photometry ; Optical ; Photometry, infrared
Keywords: astrometry - stars: formation - stars: kinematics and dynamics
Abstract:
The high-precision astrometry from the second data release of the Gaia
mission (Cat. I/345) has made it possible to greatly improve the census
of members of nearby clusters and associations. I have applied the Gaia
data to the Taurus star-forming region, refining the sample of known
members and identifying candidates for undiscovered members. The resulting
samples of members and candidates provide the best constraints to date
on the distribution of ages and the initial mass function (IMF) in Taurus.
Several studies over the last 30 years have proposed the existence of
a population of older stars (≳10 Myr) that is associated with the Taurus
clouds. The data from Gaia demonstrate that such a population does not
exist. Meanwhile, previous IMF estimates for small fields surrounding the
Taurus aggregates have exhibited a surplus of K7-M0 stars (0.7-0.8 M☉)
relative to star-forming clusters such as IC 348 and the Orion Nebula
Cluster. However, that difference disappears when the new census of the
entire region is considered, which should be complete for spectral types
earlier than M6-M7 at AJ<1. Thus, there is little variation in the stellar
IMF across the 3-4 orders of magnitude in stellar density that are present
in nearby star-forming regions. Finally, I note that the proper motions of
two previously known members, KPNO 15 and 2MASS J04355209+2255039, indicate
that they may have been ejected from the same location within the L1536
cloud ∼7200 years ago.
Description:
To examine the kinematics and distances of known members of Taurus, I have
considered the 427 stars that were adopted as members by Esplin & Luhman
(2017, J/AJ/154/134). For each star, I identified the closest counterpart
in Gaia DR2 (Cat. I/345) within 1" of its position in the Point Source
Catalog from the Two Micron All Sky Survey (2MASS; Skrutskie et al. 2006,
Cat. VII/233). Some members had multiple Gaia counterparts, all of which
corresponded to the known components of binary systems. I retrieved the
photometry, parallaxes, proper motions, and radial velocities for those
counterparts from DR2. Multiple systems in which the components were
unresolved from each other in the photometric catalogs utilized by
Esplin & Luhman (2017, J/AJ/154/134) appeared as single entries in the list
of members from that study. Gaia provides resolved measurements for
companions in 13 of those systems, so they are now counted as separate
objects.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 232 438 Members of Taurus
table5.dat 164 91 Candidate members of group 29
(as defined in Oh+ 2017, J/AJ/153/257)
table6.dat 164 62 Candidate members of Taurus
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
III/252 : Pulkovo radial velocities for 35493 HIP stars (Gontcharov, 2006)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+A/312/439 : New T Tauri stars in Taurus-Auriga (Wichmann+, 1996)
J/ApJS/155/175 : MK Classification of Bright Star Supplement (Abt, 2004)
J/ApJ/647/1180 : Infrared photometry of Taurus SFR (Luhman+, 2006)
J/ApJS/186/111 : Spitzer observations of Taurus members (Luhman+, 2010)
J/ApJS/186/259 : Taurus Spitzer survey: new candidate members (Rebull+, 2010)
J/ApJ/745/119 : Close companions to young stars. I. ChaI + Tau (Nguyen+, 2012)
J/ApJ/784/126 : Infrared photometry of all known members in Taurus
(Esplin+, 2014)
J/ApJ/786/97 : Photospheric properties of T Tauri stars (Herczeg+, 2014)
J/AJ/153/46 : Spectroscopy of candidate members in Taurus (Luhman+, 2017)
J/AJ/153/257 : Comoving stars in Gaia DR1 (Oh+, 2017)
J/AJ/154/134 : Planetary-mass brown dwarfs in the Taurus SFR (Esplin+, 2017)
J/ApJ/838/150 : The Taurus-Auriga ecosystem. I. (Kraus+, 2017)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- 2MASS ? 2MASS Point Source Catalog source name
(JHHMMSSss+DDMMSSs)
19- 37 A19 --- UGCS ? UKIDSS Galactic Clusters Survey source name
(1)
39- 61 A23 --- OName ? Other source name
63- 71 F9.6 deg RAdeg Right Ascension in decimal degrees (J2000)
73- 81 F9.6 deg DEdeg Declination in decimal degrees (J2000)
83- 89 A7 --- rPos Reference for Right Ascension and Declination
(2)
91- 95 A5 --- SpType ? Adopted spectral type (3)
97-102 F6.3 mas/yr pmRA [-1.889/28.987]? Gaia DR2 proper motion in
right ascension (pmRA*cosDE)
104-108 F5.3 mas/yr e_pmRA [0.067/4.285]? Error in pmRA
110-116 F7.3 mas/yr pmDE [-30.258/-8.093]? Gaia DR2 proper motion in
declination
118-122 F5.3 mas/yr e_pmDE [0.04/3.452]? Error in pmDE
124-129 F6.3 mas plx [2.257/11.856]? Gaia DR2 parallax
131-135 F5.3 mas e_plx [0.035/2.407]? Error in plx
137-142 F6.3 km/s RV [8.9/22.45]? Radial velocity
144-148 F5.3 km/s e_RV [0.01/3.1]? Error in RVel
150-151 I2 --- r_RV [1/13]? Radial velocity reference (4)
153-158 F6.2 km/s U [-20.34/-9.64]? U component of space velocity
160-163 F4.2 km/s e_U [0.04/3.02]? Error in U
165-170 F6.2 km/s V [-16.85/-8.6]? V component of space velocity
172-175 F4.2 km/s e_V [0.07/2.44]? Error in V
177-182 F6.2 km/s W [-12.86/-2.56]? W component of space velocity
184-187 F4.2 km/s e_W [0.03/1.68]? Error in W
189-194 F6.3 mag Gmag [6.518/21.165]? Gaia DR2 G magnitude
196-200 F5.3 mag e_Gmag [0.001/0.065]? Error in Gmag
202-207 F6.3 mag GBPmag [6.532/22.284]? Gaia DR2 GBP magnitude
209-213 F5.3 mag e_GBPmag [0.001/0.731]? Error in GBPmag
215-220 F6.3 mag GRPmag [6.529/19.212]? Gaia DR2 GRP magnitude
222-226 F5.3 mag e_GRPmag [0.001/0.197]? Error in GRPmag
228-232 A5 --- Pop ? Color code for the kinematic populations
in Figures 2-11 of this paper
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Note (1): Based on coordinates from Data Release 10 of the UKIDSS Galactic
Clusters Survey for stars with Ks>10 from the Two Micron All Sky Survey
(2MASS, Skrutskie et al. 2006, Cat. VII/233).
Note (2): Reference as follows:
Gaia = Gaia DR2 (Cat. I/345);
2MASS = The 2MASS Point Source Catalog (Cat. II/246);
UKIDSS = UKIDSS Data Release 10;
Spitzer = Images from the Spitzer Space Telescope (Luhman et al. 2010,
J/ApJS/186/111).
Note (3): Spectral types adopted by Luhman et al. (2017, J/AJ/153/46) and
Esplin & Luhman (2017, J/AJ/154/134) with the exception of HD 283641,
RX J0422.1+1934, L1551-55, RX J0507.2+2437, HD 28354, HD 283782, HD 30378,
PSO J065.8871+19.8386/PSO J071.6033+17.0281/PSO J074.1999+29.2197, and
PSO J071.3189+31.6888/PSO J076.2495+31.7503, whose types are from
Wichmann et al. (2000A&A...359..181W 2000A&A...359..181W), Martin & Magazzu (1999A&A...342..173M 1999A&A...342..173M),
Herczeg & Hillenbrand (2014, J/ApJ/786/97), Briceno et al.
(1999AJ....118.1354B 1999AJ....118.1354B), Abt (2004, J/ApJS/155/175), Wichmann et al. (1996,
J/A+A/312/439), Racine (1968AJ.....73..233R 1968AJ.....73..233R), Esplin & Luhman (in
preparation), and this work, respectively.
Note (4): Radial velocity reference as follows:
1 = Nguyen et al. (2012, J/ApJ/745/119);
2 = Gontcharov (2006, Cat. III/252);
3 = Muzerolle et al. (2003ApJ...592..266M 2003ApJ...592..266M);
4 = White & Basri (2003ApJ...582.1109W 2003ApJ...582.1109W);
5 = Torres et al. (2013ApJ...773...40T 2013ApJ...773...40T);
6 = Hartmann et al. (1986ApJ...309..275H 1986ApJ...309..275H);
7 = Wichmann et al. (2000A&A...359..181W 2000A&A...359..181W);
8 = Kraus et al. (2017, J/ApJ/838/150);
9 = Reipurth et al. (1990A&A...235..197R 1990A&A...235..197R);
10 = Rice et al. (2010ApJS..186...63R 2010ApJS..186...63R);
11 = Scelsi et al. (2008A&A...490..601S 2008A&A...490..601S);
12 = Mathieu et al. (1997AJ....113.1841M 1997AJ....113.1841M);
13 = Gaia DR2 (Cat. I/345).
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Byte-by-byte Description of file: table5.dat table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- 2MASS ? 2MASS Point Source Catalog source name
(JHHMMSSss+DDMMSSs)
19- 33 A15 --- OName ? Other source name (only in Table 5)
35- 43 F9.6 deg RAdeg Right Ascension in decimal degrees (J2000)
45- 53 F9.6 deg DEdeg Declination in decimal degrees (J2000)
55- 60 F6.3 mas/yr pmRA [-5.79/14.318] Gaia DR2 proper motion in right
ascension (pmRA*cosDE)
62- 66 F5.3 mas/yr e_pmRA [0.06/0.663] Error in pmRA
68- 74 F7.3 mas/yr pmDE [-27.385/-12.524] Gaia DR2 proper motion in
declination
76- 80 F5.3 mas/yr e_pmDE [0.034/0.474] Error in pmDE
82- 86 F5.3 mas plx [4.906/8.595] Gaia DR2 parallax
88- 92 F5.3 mas e_plx [0.036/0.43] Error in plx
94- 99 F6.3 mag Gmag [7.136/18.553] Gaia DR2 G magnitude
101-105 F5.3 mag e_Gmag [0.001/0.006] Error in Gmag
107-112 F6.3 mag GBPmag [7.179/20.836]? Gaia DR2 GBP magnitude
114-118 F5.3 mag e_GBPmag [0.001/0.198]? Error in GBPmag
120-125 F6.3 mag GRPmag [7.103/17.007]? Gaia DR2 GRP magnitude
127-131 F5.3 mag e_GRPmag [0.001/0.02]? Error in GRPmag
133-137 F5.2 mag Jmag [7/14.56]? 2MASS J magnitude
139-142 F4.2 mag e_Jmag [0.02/0.04]? Error in Jmag
144-148 F5.2 mag Hmag [7.03/13.96]? 2MASS H magnitude
150-153 F4.2 mag e_Hmag [0.01/0.05]? Error in Hmag
155-159 F5.2 mag Ksmag [7.02/13.56]? 2MASS Ks magnitude
161-164 F4.2 mag e_Ksmag [0.01/0.05]? Error in Ksmag
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 16-Apr-2019