J/AJ/158/54 New Taurus members from stellar to planetary masses (Esplin+, 2019)
A survey for new members of Taurus from stellar to planetary masses.
Esplin T.L., Luhman K.L.
<Astron. J., 158, 54 (2019)>
=2019AJ....158...54E 2019AJ....158...54E (SIMBAD/NED BibCode)
ADC_Keywords: Star Forming Region ; Populations, stellar ; Spectral types ;
Proper motions ; Photometry, infrared ; Equivalent widths ;
Spectra, optical ; Spectra, infrared
Keywords: brown dwarfs - protoplanetary disks - stars: low-mass -
stars: formation
Abstract:
We present a large sample of new members of the Taurus star-forming region
that extend from stellar to planetary masses. To identify candidate members
at substellar masses, we have used color-magnitude diagrams and proper
motions measured with several wide-field optical and infrared (IR) surveys.
At stellar masses, we have considered the candidate members that were found
in a recent analysis of high-precision astrometry from the Gaia mission.
Using new and archival spectra, we have measured spectral types and
assessed membership for these 161 candidates, 79 of which are classified
as new members. Our updated census of Taurus now contains 519 known
members. According to Gaia data, this census should be nearly complete
for spectral types earlier than M6-M7 at AJ<1. For a large field
encompassing ∼72% of the known members, the census should be complete
for K<15.7 at AJ<1.5, which corresponds to ∼5-13 MJup for ages of
1-10 Myr based on theoretical evolutionary models. Our survey has doubled
the number of known members at ≥M9 and has uncovered the faintest known
member in MK, which should have a mass of ∼3-10 MJup for ages of
1-10 Myr. We have used mid-IR photometry from the Spitzer Space Telescope
and the Wide-field Infrared Survey Explorer to determine whether the new
members exhibit excess emission that would indicate the presence of
circumstellar disks. The updated disk fraction for Taurus is ∼0.7 at =<M3.5
and ∼0.4 at >M3.5.
Description:
For our census of Taurus, we begin with the 438 objects adopted as
members by Luhman (2018, J/AJ/156/271), which were vetted for contaminants
using the proper motions and parallaxes from Gaia DR2 (Cat. I/345). When
the 79 new members from our survey are included, we arrive at a catalog
of 519 known members of Taurus, which are presented in Table 1.
We have obtained spectra of 140 candidate members of Taurus, three known
companions that lack spectral classifications, and the primary for one
of the latter stars. We also searched for publicly available spectra of
our candidates in the data archives of observatories and spectroscopic
surveys, finding spectra with sufficient signal-to-noise ratios (S/Ns)
for 38 objects. Those archival observations consist of 31 optical spectra
from the third data release of the Large Sky Area Multi-Object Fiber
Spectroscopic Telescope survey (LAMOST; Cui et al. 2012RAA....12.1197C 2012RAA....12.1197C;
Zhao et al. 2012RAA....12..723Z 2012RAA....12..723Z) and seven IR spectra collected through
programs GN-2017A-Q-81, GN-2017B-Q-35 (L. Albert), and GN-2017B-Q-19
(E. Magnier) with the Gemini Near-Infrared Spectrograph (GNIRS;
Elias et al. 2006SPIE.6269E..4CE). We present spectra for a total of
168 objects, some of which were observed with multiple instruments.
We performed our spectroscopy with the Red Channel Spectrograph
(Schmidt et al. 1989PASP..101..713S 1989PASP..101..713S) and the MMT and Magellan Infrared
Spectrograph (MMIRS; McLeod et al. 2012PASP..124.1318M 2012PASP..124.1318M) at the MMT; GNIRS
and the Gemini Multi-Object Spectrograph (GMOS; Hook et al.
2004PASP..116..425H 2004PASP..116..425H) at Gemini North; SpeX (Rayner et al.
2003PASP..115..362R 2003PASP..115..362R) at the NASA Infrared Telescope Facility (IRTF);
and the Low-Resolution Spectrograph 2 (LRS2; Chonis et al.
2014SPIE.9147E..0AC, 2016SPIE.9908E..4CC) at the Hobby-Eberly Telescope
(HET). The date and instrument for each object are listed in Table 4.
Objects:
-------------------------------------------------------------
RA (ICRS) DE Designation(s)
-------------------------------------------------------------
04 41.0 +25 52 Taurus = NAME Taurus Dark Cloud
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File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 471 519 Members of Taurus
table4.dat 130 168 Spectroscopic data for candidate members
of Taurus
list.dat 155 153 List of spectra from Table 4
fig15/* . 60 Optical spectra of candidate members of Taurus
from Table 4 and Figure 15 of this paper
fig16a/* . 100 Near-IR spectra of candidate members of Taurus
from Table 4 and Figure 16 of this paper
fig16b/* . 24 Dereddened near-IR spectra of candidate members
of Taurus from Table 4 and Figure 16 of this
paper
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/ApJ/578/914 : Low-mass stars in Taurus (Hartmann, 2002)
J/ApJ/645/676 : Spatial distribution of brown dwarfs in Taurus (Luhman+, 2006)
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/784/126 : Infrared photometry of all known members in Taurus
(Esplin+, 2014)
J/AJ/153/46 : Spectroscopy of candidate members in Taurus (Luhman+, 2017)
J/AJ/154/46 : Proper motions and photometry for members of Cha I
(Esplin+, 2017)
J/AJ/154/134 : Planetary-mass brown dwarfs in the Taurus SFR (Esplin+, 2017)
J/AJ/156/271 : The stellar membership of the Taurus SFR (Luhman, 2018)
J/ApJ/858/41 : PS1 proper-motion survey for brown dwarfs. I. Taurus
(Zhang+, 2018)
J/ApJ/859/33 : GOBELINS. IV. VLBA obs. of Taurus (Galli+, 2018)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- 2MASS 2MASS Point Source Catalog name
(JHHMMSSss+DDMMSSs)
20- 38 A19 --- UGCS UKIDSS Galactic Clusters Survey name
(JHHMMSS.ss+DDMMSS.s) (1)
40- 58 I19 --- Gaia ? Gaia DR2 name
60- 82 A23 --- OName Other source name
84- 92 F9.6 deg RAdeg Right Ascension in decimal degrees (J2000)
94-102 F9.6 deg DEdeg Declination in decimal degrees (J2000)
104-110 A7 --- rPos Reference for RAdeg and DEdeg (2)
112-116 A5 --- SpType Adopted spectral type (3)
118-123 F6.3 mas/yr pmRA [-1.889/28.987]? Proper motion in RA from
Gaia DR2 (pmRA*cosDE)
125-129 F5.3 mas/yr e_pmRA [0.067/4.285]? Error in pmRA
131-137 F7.3 mas/yr pmDE [-30.258/-8.093]? Proper motion in DE from
Gaia DR2
139-143 F5.3 mas/yr e_pmDE [0.04/3.452]? Error in pmDE
145-150 F6.3 mas Plx [2.257/14.425]? Parallax from Gaia DR2
152-156 F5.3 mas e_Plx [0.035/2.407]? Error in Plx
158 A1 --- f_Plx [*] Flag on Plx (4)
160-165 F6.3 mag Gmag [6.518/21.439]? G magnitude from Gaia DR2
167-171 F5.3 mag e_Gmag [0.001/0.065]? Error in Gmag
173-178 F6.3 mag GBPmag [6.532/22.284]? GBP magnitude from Gaia DR2
180-184 F5.3 mag e_GBPmag [0.001/0.731]? Error in GBPmag
186-191 F6.3 mag GRPmag [6.529/19.212]? GRP magnitude from Gaia DR2
193-197 F5.3 mag e_GRPmag [0.001/0.197]? Error in GRPmag
199-204 F6.2 --- RUWE [0.81/120.5]? Re-normalized unit weight error
(5)
206-210 A5 --- Pop Population from Luhman (2018, J/AJ/156/271)
212-216 F5.1 mas/yr pmRAIR [-50/39.6]? Proper motion in RA from
2MASS/WFCAM/IRAC
218-221 F4.1 mas/yr e_pmRAIR [0/83]? Error in pmRAIR
223-227 F5.1 mas/yr pmDEIR [-88.1/63.6]? Proper motion DE from
2MASS/WFCAM/IRAC
229-232 F4.1 mas/yr e_pmDEIR [0/74.6]? Error in pmDEIR
234-238 F5.2 mag Jmag [5.94/19.55]? J band magnitude
240-243 F4.2 mag e_Jmag [0/0.08]? Error in Jmag
245 I1 --- r_Jmag [1/5]? Reference for Jmag (6)
247-251 F5.2 mag Hmag [5.06/17.86]? H band magnitude
253-256 F4.2 mag e_Hmag [0/0.19]? Error in Hmag
258 I1 --- r_Hmag [1/5]? Reference for Hmag (6)
260-264 F5.2 mag Kmag [4.23/16.79]? K or Ks band magnitude
266-269 F4.2 mag e_Kmag [0/9.99]? Error in Kmag
271 I1 --- r_Kmag [1/4]? Reference for Kmag (6)
273-277 F5.2 mag 3.6mag [5.86/15.64]? Spitzer [3.6] band magnitude
279-282 F4.2 mag e_3.6mag [0.02/0.17]? Error in 3.6mag
284-288 A5 --- f_3.6mag Flag on 3.6mag (7)
290-294 F5.2 mag 4.5mag [5.03/15.36]? Spitzer [4.5] band magnitude
296-299 F4.2 mag e_4.5mag [0.02/0.12]? Error in 4.5mag
301-305 A5 --- f_4.5mag Flag on 4.5mag (7)
307-311 F5.2 mag 5.8mag [2.59/14.53]? Spitzer [5.8] band magnitude
313-316 F4.2 mag e_5.8mag [0.03/0.13]? Error in 5.8mag
318-322 A5 --- f_5.8mag Flag on 5.8mag (7)
324-328 F5.2 mag 8.0mag [2.76/14.49]? Spitzer [8.0] band magnitude
330-333 F4.2 mag e_8.0mag [0.03/0.18]? Error in 8.0mag
335-339 A5 --- f_8.0mag Flag on 8.0mag (7)
341-344 F4.2 mag 24mag [0.55/9.82]? Spitzer [24] band magnitude
346-349 F4.2 mag e_24mag [0.04/0.31]? Error in 24mag
351-355 A5 --- f_24mag Flag on 24mag (7)
357 I1 --- Ref-S [1/4]? Reference for Spitzer photometry (8)
359-363 F5.2 mag W1mag [3.25/15.96]? WISE W1 band magnitude
365-368 F4.2 mag e_W1mag [0.02/0.14]? Error in W1mag
370-374 A5 --- f_W1mag Flag on W1mag (7)
376-380 F5.2 mag W2mag [6.03/15.73]? WISE W2 band magnitude
382-385 F4.2 mag e_W2mag [0.02/0.38]? Error in W2mag
387-391 A5 --- f_W2mag Flag on W2mag (7)
393-397 F5.2 mag W3mag [-0.21/12.01]? WISE W3 band magnitude
399-402 F4.2 mag e_W3mag [0.01/0.35]? Error in W3mag
404-408 A5 --- f_W3mag Flag on W3mag (7)
410-414 F5.2 mag W4mag [-2.51/8.69]? WISE W4 band magnitude
416-419 F4.2 mag e_W4mag [0.01/0.47]? Error in W4mag
421-425 A5 --- f_W4mag Flag on W4mag (7)
427-428 A2 --- Exc4.5 Excess present in [4.5]?
430-431 A2 --- Exc8.0 Excess present in [8.0]?
433 A1 --- Exc24 Excess present in [24]?
435-436 A2 --- ExcW2 Excess present in W2?
438 A1 --- ExcW3 Excess present in W3?
440 A1 --- ExcW4 Excess present in W4?
442-456 A15 --- Disk Disk type (9)
458-462 F5.2 mag Aj [0/11.4]? Extinction in J
464-471 A8 --- f_Aj Method for estimating Aj (10)
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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 2MASS.
Note (2): Reference as follows:
2MASS = 2MASS Point Source Catalog (Cat. II/246);
Gaia = Gaia DR2 (Cat. I/345);
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),
Esplin & Luhman (2017, J/AJ/154/46), and Luhman (2018, J/AJ/156/271) for
previously known members and types measured in this work for new members
(Table 3).
Note (4): Flag as follows:
* = Discrepant parallax relative to other members of Taurus, as noted in
Luhman (2018, J/AJ/156/271) and the Appendix.
Note (5): From Lindegren (2018, Re-normalising the Astrometric Chi-square in
Gaia DR2 GAIA-C3-TN-LU-LL-124-01,
http://www.rssd.esa.int/doc_fetch.php?id=3757412).
Note (6): Reference as follows:
1 = 2MASS Point Source Catalog (Cat. II/246);
2 = UKIRT Hemisphere Survey;
3 = UKIDSS Data Release 10;
4 = Our WFCAM photometry (Sec 3.1.3);
5 = WIRCam photometry.
Note (7): Flag as follows:
nodet = Non-detection;
sat = Saturated;
out = Outside of the camera's field of view;
bl = Photometry may be affected by blending with a nearby star;
bin = Includes an unresolved binary companion;
ext = Not explained in this paper;
unres = Too close to a brighter star to be detected;
false = Detection from WISE catalog appears false or unreliable based on
visual inspection.
Note (8): Reference as follows:
1 = Luhman et al. (2010, J/ApJS/186/111);
2 = Esplin et al. (2014, J/ApJ/784/126);
3 = Esplin & Luhman (2017, J/AJ/154/134);
4 = This work.
Note (9): The disks are assigned to the following categories:
full = Optically thick full (primordial) disks with no large
gaps or holes that affect the mid-IR spectral energy
distribution (SED);
trans/transitional = Optically thick transitional disks with large inner
holes;
ev/evolved = Optically thin evolved disks with no large gaps;
ev trans = Optically thin evolved transitional disks with large
inner holes;
debris = Optically thin debris disks that are composed of
second-generational dust from planetesimal collisions;
0/I = Protostar+disk+infalling envelope;
II = Star+disk;
III = Star without disk.
Note (10): Method as follows:
J-H/J-K = Derived from these colors assuming photospheric near-IR colors
(Luhman et al. 2010, J/ApJS/186/111);
CTTS = Derived from J-H and H-K colors assuming intrinsic colors of
classical T Tauri stars from Meyer et al. (1997AJ....114..288M 1997AJ....114..288M);
opt spec = Derived from an optical spectrum;
IR spec = Derived from an infrared spectrum;
1 = Briceno et al. (1998AJ....115.2074B 1998AJ....115.2074B);
2 = Luhman (2000ApJ...544.1044L 2000ApJ...544.1044L);
3 = Strom & Strom (1994ApJ...424..237S 1994ApJ...424..237S);
4 = Beck (2007AJ....133.1673B 2007AJ....133.1673B);
5 = White & Ghez (2001ApJ...556..265W 2001ApJ...556..265W);
6 = DeWarf et al. (2003ApJ...590..357D 2003ApJ...590..357D);
7 = Calvet et al. (2004AJ....128.1294C 2004AJ....128.1294C).
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 24 A24 --- Name Source name (G1)
26- 34 F9.6 deg RAdeg Right Ascension in decimal degrees (J2000)
36- 44 F9.6 deg DEdeg Declination in decimal degrees (J2000)
46- 56 A11 --- SpType Spectral type(s)
58 A1 --- l_EWLi [<] Limit flag on EWLi
59- 62 F4.2 0.1nm EWLi [0.1/0.95]? Equivalent width of Li (Å)
64- 67 F4.2 0.1nm e_EWLi [0.05/0.2]? Error in EWLi (Å)
69- 91 A23 --- Inst Instrument(s)
93-103 A11 "date" Date1 First date of observation
105-115 A11 "date" Date2 Second date of observation
117-127 A11 "date" Date3 Third date of observation
129-130 A2 --- Memb Member of Taurus? (Y=yes, N=No)
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 24 A24 --- Name Source name (G1)
26- 39 A14 --- FileName15 Name of FITS file, in subdirectory fig15 (1)
41- 68 A28 --- FileName16a1 Name of FITS file, in subdirectory fig16a (2)
70- 96 A27 --- FileName16a2 Name of FITS file, in subdirectory fig16a (2)
98-126 A29 --- FileName16b1 Name of FITS file, in subdirectory fig16b (2)
128-155 A28 --- FileName16b2 Name of FITS file, in subdirectory fig16b (2)
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Note (1): These data are at a resolution of 3-8 Angstroms. The fluxes are
normalized to the flux at 7500 Angstroms.
Note (2): The fluxes are normalized to the flux at 1.68 microns.
--------------------------------------------------------------------------------
Global notes:
Note (G1): Identifications from the 2MASS Point Source Catalog (Cat. II/246)
when available. Otherwise, they are based on coordinates from Data Release 10
of the UKIDSS Galactic Clusters Survey.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 17-Sep-2019