J/AJ/153/46 Spectroscopy of candidate members in Taurus (Luhman+, 2017)
A Survey for new members of the Taurus star-forming region with the Sloan
Digital Sky Survey.
Luhman K.L., Mamajek E.E., Shukla S.J., Loutrel N.P.
<Astron. J., 153, 46-46 (2017)>
=2017AJ....153...46L 2017AJ....153...46L (SIMBAD/NED BibCode)
ADC_Keywords: Associations, stellar ; Stars, dwarfs ; Spectra, infrared ;
Spectral types ; Extinction
Keywords: brown dwarfs - protoplanetary disks - stars: formation -
stars: low-mass - stars: luminosity function, mass function -
stars: pre-main sequence
Abstract:
Previous studies have found that ∼1deg2 fields surrounding the
stellar aggregates in the Taurus star-forming region exhibit a surplus
of solar-mass stars relative to denser clusters like IC 348 and the
Orion Nebula Cluster. To test whether this difference reflects mass
segregation in Taurus or a variation in the initial mass function, we
have performed a survey for members of Taurus across a large field
(∼40deg2) that was imaged by the Sloan Digital Sky Survey (SDSS). We
obtained optical and near-infrared spectra of candidate members
identified with those images and the Two Micron All Sky Survey, as
well as miscellaneous candidates that were selected with several other
diagnostics of membership. We have classified 22 of the candidates as
new members of Taurus, which includes one of the coolest known members
(M9.75). Our updated census of members within the SDSS field shows a
surplus of solar-mass stars relative to clusters, although it is less
pronounced than in the smaller fields toward the stellar aggregates
that were surveyed for previously measured mass functions in Taurus.
In addition to spectra of our new members, we include in our study
near-IR spectra of roughly half of the known members of Taurus, which
are used to refine their spectral types and extinctions. We also
present an updated set of near-IR standard spectra for classifying
young stars and brown dwarfs at M and L types.
Description:
We have obtained optical and near-infrared spectra of candidate
members of Taurus. The spectra were collected with the Gemini
Near-Infrared Imager (NIRI) using the K-band grism and 0.47'' slit
(1.9-2.5µm, R=700), the Gemini Multi-Object Spectrograph (GMOS)
using the 400line/mm grating and 0.75'' slit (0.56-1µm, R=1500),
the Marcario Low-Resolution Spectrograph (LRS) on the Hobby-Eberly
Telescope (HET) using the G3 grism and 2'' slit (0.63-0.91µm,
R=1100), and SpeX at the NASA Infrared Telescope Facility (IRTF) using
either the prism or SXD mode (R=150/750) and 0.8'' slit
(0.8-2.5µm).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 170 414 Members of Taurus
table2.dat 82 22 New members of Taurus in spectroscopic sample
table3.dat 84 18 Nonmembers in the spectroscopic sample
table4.dat 105 40 Spectral types for known members of TW Hya
association (TWA)
table5.dat 66 68 Data for construction of standard spectra
figure15.dat 60 31 Standard spectra for classifying young stars
and brown dwarfs
refs.dat 94 103 References
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See also:
II/328 : AllWISE Data Release (Cutri+ 2013)
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
III/182 : HDE Charts: positions, proper motions (Nesterov+ 1995)
J/MNRAS/453/2220 : Early-type Sco-Cen members with RVs (Murphy+, 2015)
J/ApJS/219/33 : BANYAN. VII. Candidate YMG members from BASS (Gagne+, 2015)
J/A+A/562/A127 : NIR integral field spectra of 15 M-L dwarfs (Bonnefoy+, 2014)
J/ApJ/784/126 : IR photometry of all known members in Taurus (Esplin+, 2014)
J/AJ/147/85 : Solar neighborhood. XXXIII. 45 M dwarfs (Riedel+, 2014)
J/ApJS/208/9 : Intrinsic colors and temperatures of PMS stars (Pecaut+, 2013)
J/ApJ/745/119 : Close companions to young stars. I. ChaI & Tau (Nguyen+, 2012)
J/AJ/140/1214 : NIR spectroscopic survey of class I YSOs (Connelley+, 2010)
J/ApJS/186/259 : Taurus Spitzer survey: new candidate members (Rebull+, 2010)
J/ApJ/703/1511 : Wide binaries in Taurus and Upper Sco (Kraus+, 2009)
J/ApJ/676/1281 : L and T dwarfs in 2MASS/SDSS (Metchev+, 2008)
J/AJ/136/1290 : Ultracool dwarfs from the 2MASS (Reid+, 2008)
J/AJ/134/411 : Properties of IC 348 members (Muench+, 2007)
J/ApJ/647/1180 : Infrared photometry of Taurus SFR (Luhman+, 2006)
J/ApJ/645/676 : Spatial distribution of brown dwarfs in Taurus (Luhman+, 2006)
J/A+A/460/695 : Search for Associations Containing Young stars (Torres+, 2006)
J/A+A/446/485 : New very low-mass members in Taurus (Guieu+, 2006)
J/AJ/132/2665 : QUEST2 BRI photometry of Taurus-Auriga PMS (Slesnick+, 2006)
J/AJ/130/1145 : YSO near-infrared properties (Doppmann+, 2005)
J/other/ARA+A/42.685 : Young stars near the Sun (Zuckerman+, 2004)
J/ApJ/593/1093 : IC 348 membership (Luhman+, 2003)
J/ApJ/525/466 : Young low-mass stars and brown dwarfs in IC348 (Luhman+, 1999)
J/A+A/312/439 : New T Tauri stars in Taurus-Auriga (Wichmann+, 1996)
J/ApJS/101/117 : UBVRIJHKLMNQ photometry in Taurus-Auriga (Kenyon+ 1995)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- 2MASS 2MASS Point Source Catalog (Cutri et al. 2003,
Cat. II/246) source name
19- 37 A19 --- WISE WISE All-Sky Source Catalog (Cutri et al. 2012,
Cat. II/311) source name (1)
39- 40 I2 h RAh Hour of Right Ascension (J2000)
42- 43 I2 min RAm Minute of Right Ascension (J2000)
45- 49 F5.2 s RAs Second of Right Ascension (J2000)
51 A1 --- DE- Sign of the Declination (J2000)
52- 53 I2 deg DEd Degree of Declination (J2000)
55- 56 I2 arcmin DEm Arcminute of Declination (J2000)
58- 61 F4.1 arcsec DEs Arcsecond of Declination (J2000)
63- 85 A23 --- Name ? Source name
87-117 A31 --- SpT ? Spectral type(s)
119-137 A19 --- r_SpT ? Reference for SpT; in refs.dat
139-149 A11 --- Date ? Date of SpeX observation
151-155 A5 --- ASpT ? Adopted spectral type
157-161 F5.2 mag AJ [0/11.4]? Extinction in J
163-170 A8 --- f_AJ ? Method of extinction estimation (either 1,
2, 3, 4, 5, 6, 7, CTTS, J-H, J-K, SpeX,
edge-on, edge-on?, na, or opt spec) (3)
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Note (1): Source names for HBC 360, HBC 361, and IRAM 04191+1522 are from the
ALLWISE Source Catalog.
Note (3): The methods are explained as follows:
SpeX = Derived from a SpeX spectrum;
CTTS = Derived from J-H and H-K colors assuming intrinsic colors of
classical T Tauri stars from from Meyer et al. 1997AJ....114..288M 1997AJ....114..288M;
opt spec = derived from an optical spectrum;
J-H = Derived from this color assuming photospheric near-infrared color;
J-K = Derived from this color assuming photospheric near-infrared color;
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: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- 2MASS 2MASS Point Source Catalog (Cutri et al. 2003,
Cat. II/246) source name
19 A1 --- f_2MASS Flag for companion on 2MASS (b or c) (1)
21- 29 A9 --- SpT Spectral type
31- 41 A11 --- Selection Basis of selection for spectroscopy (CMDs,
Hα, X-ray, IR, pm, WIRCam/IRAC,
or companion?) (G1)
43- 59 A17 --- Inst Telescope and instrument for the spectroscopy
(Gemini/NIRI, HET/LRS, HET/LRS,IRTF/SpeX,
or IRTF/SpeX) (G2)
61- 71 A11 "Y:M:D" Date1 Date for the spectroscopy
73- 82 A10 "Y:M:D" Date2 Second date for the spectroscopy, if any
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Note (1): The flag codes are defined as follows:
b = Candidate companion to IRAS 04125+2902;
c = GZ Aur A and B. Both components were observed by SpeX. Only the
primary was observed by Low-Resolution Spectrograph (LRS).
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- --- [2MASS]
7- 23 A17 --- 2MASS 2MASS Point Source Catalog (Cutri et al. 2003,
Cat. II/246) source name
25- 28 A4 --- --- [WISE]
30- 48 A19 --- WISE WISE All-Sky Source Catalog (Cutri et al. 2012,
Cat. II/311) source name
50- 55 A6 --- SpT Spectral type
57- 60 A4 --- Sel Basis of selection for spectroscopy
(CMDs or IR) (G1)
62- 72 A11 --- Inst Telescope and instrument for (Gemini/GMOS,
Gemini/NIRI, or IRTF/SpeX) (G2)
74- 84 A11 "Y:M:D" Date Date for the spectroscopy
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- TWA TW Hya association (TWA) number (1)
3 A1 --- m_TWA TWA component (A or B)
5- 21 A17 --- 2MASS 2MASS Point Source Catalog (Cutri et al. 2003,
Cat. II/246) source name
23- 38 A16 --- OName Other name
40- 79 A40 --- SpT Spectral type(s) (2)
81- 99 A19 --- r_SpT Reference(s); in refs.dat file
101-105 A5 --- ASpT Adopted spectral type
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Note (1): TWA names 39 through 43 were assigned by Gagne et al.
2017ApJS..228...18G 2017ApJS..228...18G.
Note (2): ir=Spectral types measured from near-infrared spectra.
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Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 23 A23 --- Name Object name (1)
25- 29 A5 --- ASpT Adopted optical spectral type
31- 36 A6 --- r_ASpT Reference(s) for ASpT
38- 48 A11 "Y:M:D" Date1 Date of SpeX observation
50- 60 A11 "Y:M:D" Date2 Second SpeX date, if any
62- 66 A5 --- r_Date2 Reference(s) for the dates; in refs.dat file
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Note (1): We list the objects used to create the standard spectra.
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Byte-by-byte Description of file: figure15.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- SpT Spectral type
6- 12 A7 --- Pop Population (younger or older)
14- 29 A16 --- FileName Name of the FITS spectrum in subdirectory
figure15
31- 60 A30 --- Template Template
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Byte-by-byte Description of file: refs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Ref Reference code
5- 23 A19 --- BibCode Bibliographic code
25- 68 A44 --- Aut Author's name
70- 94 A25 --- Com Comment
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Global Notes:
Note (G1): Sources were candidate members as follows:
WIRCam/IRAC = Red WIRCam/Infrared Array Camera (WIRCam/IRAC) colors;
companion? = Possible companionship to known Taurus members;
X-ray = X-ray emission;
CMDs = Color-Magnitude Diagrams;
Ha = Hα emission;
IR = Mid-infrared excess emission;
pm = Proper motions.
Note (G2): The codes for the telescopes and instruments are defined as follows:
Gemini/NIRI = Gemini Near-Infrared Imager (NIRI);
Gemini/GMOS = Gemini Multi-Object Spectrograph (GMOS);
HET/LRS = Marcario Low-Resolution Spectrograph (LRS) on the
Hobby-Eberly Telescope (HET);
IRTF/SpeX = Spex at the NASA Infrared Telescope Facility (IRTF) on
Mauna Kea.
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 21-Jun-2017