J/ApJ/771/110 Early-type stars in Taurus-Auriga (Mooley+, 2013)
B- and A-type stars in the Taurus-Auriga star-forming region.
Mooley K., Hillenbrand L., Rebull L., Padgett D., Knapp G.
<Astrophys. J., 771, 110 (2013)>
=2013ApJ...771..110M 2013ApJ...771..110M
ADC_Keywords: Radial velocities ; Stars, A-type ; Stars, B-type ;
Proper motions ; Spectral types ; Stars, distances
Keywords: ISM: clouds; stars: early-type; stars: formation;
stars: variables: T Tauri, Herbig Ae/Be
Abstract:
We describe the results of a search for early-type stars associated
with the Taurus-Auriga molecular cloud complex, a diffuse nearby
star-forming region noted as lacking young stars of intermediate and
high mass. We investigate several sets of possible O, B, and early A
spectral class members. The first is a group of stars for which
mid-infrared images show bright nebulae, all of which can be
associated with stars of spectral-type B. The second group consists of
early-type stars compiled from (1) literature listings in SIMBAD, (2)
B stars with infrared excesses selected from the Spitzer Space
Telescope survey of the Taurus cloud (Rebull et al. 2010,
J/ApJS/186/259), (3) magnitude- and color-selected point sources from
the Two Micron All Sky Survey (Skrutskie et al. 2006, VII/233), and
(4) spectroscopically identified early-type stars from the Sloan
Digital Sky Survey coverage of the Taurus region (Finkbeiner et al.
2004AJ....128.2577F 2004AJ....128.2577F; Knapp et al. 2007AAS...211.2907K 2007AAS...211.2907K). We evaluated
stars for membership in the Taurus-Auriga star formation region based
on criteria involving: spectroscopic and parallactic distances, proper
motions and radial velocities, and infrared excesses or line emission
indicative of stellar youth. For selected objects, we also model the
scattered and emitted radiation from reflection nebulosity and compare
the results with the observed spectral energy distributions to further
test the plausibility of physical association of the B stars with the
Taurus cloud. This investigation newly identifies as probable Taurus
members three B-type stars: HR 1445 (HD 28929), τ Tau (HD 29763),
72 Tau (HD 28149), and two A-type stars: HD 31305 and HD 26212, thus
doubling the number of stars A5 or earlier associated with the Taurus
clouds. Several additional early-type sources including HD 29659 and
HD 283815 meet some, but not all, of the membership criteria and
therefore are plausible, though not secure, members.
Description:
Optical spectra follow-up were obtained at the Palomar 200 inch Hale
telescope on 2010 December 4 using the Double Spectrograph (DBSP). The
data have medium spectral resolution (R∼7800 and 10419 in the blue and
red channels, respectively). Spectra for two stars (HD 27659 and
HD 26212) were taken on 2011 September 2 using a different
configuration resulting in a much lower resolution and a larger
wavelength coverage.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 132 328 List of candidate early-type stars with
various selection methods
table4.dat 156 34 Spectral types derived through new spectroscopy
table6.dat 162 13 Final List of early-type stars showing
indications of membership with Taurus
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See also:
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
VII/244 : Atlas and Catalog of Dark Clouds (Dobashi+, 2005)
III/23 : MK Classification for OB Stars (Lesh 1968)
J/ApJS/196/4 : New young star candidates in Taurus-Auriga (Rebull+, 2011)
J/ApJ/731/8 : Multiple star formation in Taurus-Auriga (Kraus+, 2011)
J/ApJ/727/64 : Young stellar groups & their most massive stars (Kirk+, 2011)
J/A+A/519/A83 : T Tau stars toward the Taurus-Auriga region (Takita+ 2010)
J/ApJS/186/259 : Taurus Spitzer survey: new candidate members (Rebull+, 2010)
J/ApJ/647/1180 : Infrared photometry of Taurus SFR (Luhman+, 2006)
J/A+A/446/485 : New very low-mass members in Taurus (Guieu+, 2006)
J/A+A/438/769 : Pre-main sequence stars Proper Motion Cat. (Ducourant+, 2005)
J/ApJ/573/359 : Rotational velocities of B stars from BSC (Abt+, 2002)
J/AJ/117/354 : OB associations from Hipparcos (de Zeeuw+, 1999)
J/A+A/325/647 : High-resolution spectra south of Taurus (Neuhaeuser+ 1997)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Group Star grouping (G1)
5- 7 I3 --- Seq Running index number
9- 31 A23 --- Name Star name
33- 41 F9.6 deg RAdeg Right Ascension in decimal degrees (J2000)
43- 51 F9.6 deg DEdeg Declination in decimal degrees (J2000)
53- 55 I3 pc dHIP [82/667]? Hipparcos derived distance
57- 59 I3 pc e_dHIP ? Lower limit uncertainty in dHIP
61- 64 I4 pc E_dHIP ? Upper limit uncertainty in dHIP
66- 70 I5 pc dSpec [16/22508]? Spectroscopic derived distance
72- 76 I5 pc e_dSpec ? Uncertainty in dSpec (1)
78- 82 F5.1 mas/yr pmRA [-35/38] Proper motion along RA; times cos(DE)
84- 87 F4.1 mas/yr e_pmRA Uncertainty in pmRA
89- 94 F6.2 mas/yr pmDE [-41/5.4] Proper motion along DE
96-100 F5.2 mas/yr e_pmDE Uncertainty in pmDE
102-107 F6.1 km/s HRV [-169/206]? Heliocentric radial velocity
109-112 F4.1 km/s e_HRV [0.9/13]? Uncertainty in HRV
114-124 A11 --- SpT MK spectral type (2)
126-128 A3 --- dC Candidate based on distance? (3)
130-132 A3 --- kC Candidate based on kinematic assessments? (4)
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Note (1): Error is the standard deviation among distances calculated using
B,V,R,J,H, and K magnitudes, as available, and underestimates true
error values; see text.
Note (2): From SIMBAD and Kharchenko et al. 2009 (Cat. I/280) for the first
three groups, with a slash (/) denoting any discrepancy between these
two compilations, and from SDSS for the fourth group. In cases where
we have derived new spectral types ourselves in this paper (see
Table 4), our types supersede those from the references.
Note (3): Star is a probable Taurus member (Y) or not (N) based on the two
distance estimates.
Note (4): Star is a probable Taurus member (Y) or not (N) based on the two
kinematic assessments: proper motion and radial velocity.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Group Star grouping (G1)
5- 7 I3 --- Seq [4/329]? Sequence number as in table 3
9- 20 A12 --- Name Star name
22- 24 F3.1 100 S/N [0.3/3.4] Signal-to-noise ratio of the
obtained spectrum
26- 29 F4.2 0.1nm EWCa [0.1/4]? CaIIK 3933.7 equivalent width
30 A1 --- f_EWCa Flag on EWCa (1)
32 A1 --- l_EWNII Limit flag on EWNII
34- 37 F4.2 0.1nm EWNII [0.01/0.5]? NII 3995.0 equivalent width
38- 40 A3 --- f_EWNII Flag on EWNII (1)
42 A1 --- l_EWHe1 Limit flag on EWHe1
44- 47 F4.2 0.1nm EWHe1 [0.01/0.7]? HeI 4009.3 equivalent width
48 A1 --- f_EWHe1 Flag on EWHe1 (1)
50- 51 A2 --- l_EWHe2 [≤ ] Limit flag on EWHe2
53- 56 F4.2 0.1nm EWHe2 [0.01/1.5]? HeI 4026.2 equivalent width
57 A1 --- f_EWHe2 Flag on EWHe2 (1)
59- 62 F4.1 0.1nm EWHd [4/17.6]? Hδ 4101.7 equivalent width
64 A1 --- l_EWHe3 Limit flag on EWHe3
66- 69 F4.2 0.1nm EWHe3 [0.05/0.5]? HeI 4120.8 equivalent width
70 A1 --- f_EWHe3 Flag on EWHe3 (1)
72 A1 --- l_EWSi Limit flag on EWSi
74- 77 F4.2 0.1nm EWSi [0.02/0.8]? SiII 4128.1, 4130.9 equivalent width
78 A1 --- f_EWSi Flag on EWSi (1)
80- 81 A2 --- l_EWHe4 [≤ ] Limit flag on EWHe4
83- 86 F4.2 0.1nm EWHe4 [0.01/0.9]? HeI 4143.7 equivalent width
87- 89 A3 --- f_EWHe4 Flag on EWHe4 (1)
91- 94 F4.1 0.1nm EWHg [4/18]? Hγ 4340.4 equivalent width
95 A1 --- f_EWHg Flag on EWHg (1)
97 A1 --- l_EWHe5 Limit flag on EWHe5
99-102 F4.2 0.1nm EWHe5 [0.1/1]? HeI 4387.9 equivalent width
103-105 A3 --- f_EWHe5 Flag on EWHe5 (1)
107 A1 --- l_EWHe6 Limit flag on EWHe6
109-113 F5.3 0.1nm EWHe6 [0.02/1.6]? HeI 4471.5 equivalent width
114 A1 --- f_EWHe6 Flag on EWHe6 (1)
116-119 F4.2 0.1nm EWMg [0.1/0.9] MgII 4491.2 equivalent width
121-124 F4.1 0.1nm EWHb [3.6/16]? Hβ 4862.3 equivalent width
125 A1 --- f_EWHb Flag on EWHb (1)
127-128 A2 --- l_EWHe7 [≤ ] Limit flag on EWHe7
130-133 F4.2 0.1nm EWHe7 [0.1/1]? HeI 4921.9 equivalent width
134 A1 --- f_EWHe7 Flag on EWHe7 (1)
136-139 F4.1 0.1nm EWHa [3.4/11]? Hα 6562.8 equivalent width
140 A1 --- f_EWHa Flag on EWHa (1)
142 A1 --- l_EWHe8 Limit flag on EWHe8
144-147 F4.2 0.1nm EWHe8 [0.01/0.7]? HeI 6678.2 equivalent width
148 A1 --- f_EWHe8 Flag on EWHe8 (1)
150-156 A7 --- SpT Derived MK spectral type
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Note (1): Flag as follows:
a = Embedded in an adjacent absorption line.
b = Hard to distinguish from noise.
c = Emission line present within the absorption line.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Mm Membership code (1)
4- 6 I3 --- Seq [19/329] Sequence number (as in table 3)
8- 16 A9 --- Name Star name
18- 32 A15 --- AName Alternative identifier
34- 35 I2 h RAh Hour of right ascension (J2000)
37- 38 I2 min RAm Minute of right ascension (J2000)
40- 44 F5.2 s RAs Second of right ascension (J2000)
46 A1 --- DE- Sign of declination (J2000)
47- 48 I2 deg DEd Degree of declination (J2000)
50- 51 I2 arcmin DEm Arcminute of declination (J2000)
53- 56 F4.1 arcsec DEs Arcsecond of declination (J2000)
58- 67 A10 --- SpT MK spectral type
69- 71 I3 pc dHIP [123/177]? Hipparcos derived distance
73- 74 I2 pc E_dHIP [13/43]? Upper limit uncertainty in dHIP
76- 77 I2 pc e_dHIP [11/29]? Lower limit uncertainty in dHIP
79 A1 --- f_dSp [d] Discrepent values for V892 Tau (2)
81- 83 I3 pc dSp [120/422]? Spectroscopic derived distance
85- 86 I2 pc e_dSp [1/52]? dSp uncertainty (3)
88 A1 --- l_Pchi2 Limit flag on Pchi2
89- 92 F4.1 --- Pchi2 The probability of proper-motion membership
(P(χ2) (see section 2.3.2)
94- 97 F4.1 km/s HRV [7.3/20.3]? Heliocentric radial velocity
99-101 F3.1 km/s e_HRV [0.9/4.1]? RV uncertainty
103-162 A60 --- Comm Comments
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Note (1): Code as follows:
pM = Probable members based on our analysis of distance and/or kinematics.
cM = Candidates with several membership indicators but that are not secure
distance and kinematic members.
nM = Stars illuminating infrared nebulae but that cannot be associated with
Taurus based on distance and kinematic criteria.
Note (2):
d = For the source V892 Tau, dSPEC=1697±1548pc, but dB=4720pc while
dK=135pc.
Note (3): Error on dSPEC corresponds to variance among calculations and
underestimates the true error.
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Global notes:
Note (G1): Group as follows:
S = O, B, and A0 stars from SIMBAD.
R10 = Additional B and early A stars proposed by Rebull et al. (2010,
Cat. J/ApJS/186/259) from infrared excess.
2M = Additional early-type candidates selected from 2MASS photometry.
KS = O, B, A stars from Knapp et al. (2007AAS...211.2907K 2007AAS...211.2907K) SDSS data
O = Other stars
Std = Spectral-type standards (for table 4)
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 22-Jan-2015