J/AJ/144/8 Spectroscopy of ∼100 G/K/M-type Sco-Cen complex members (Song+, 2012)
New members of the Scorpius-Centaurus complex and ages of its sub-regions.
Song I., Zuckerman B., Bessell M.S.
<Astron. J., 144, 8 (2012)>
=2012AJ....144....8S 2012AJ....144....8S
ADC_Keywords: Associations, stellar ; Stars, M-type ; Stars, G-type ;
Stars, K-type ; Photometry, infrared ; Photometry, UBV ;
Space velocities ; Equivalent widths ; Radial velocities
Keywords: open clusters and associations: individual (Scorpius OB2, Lower
Centaurus-Crux, Upper Centaurus-Lupus, Upper Scorpius) -
stars: activity - stars: kinematics and dynamics -
stars: pre-main sequence
Abstract:
We have spectroscopically identified ∼100 G-, K-, and M-type members
of the Scorpius-Centaurus complex. To deduce the age of these young
stars we compare their Li λ6708 absorption line strengths
against those of stars in the TW Hydrae association and
β Pictoris moving group. These line strengths indicate that
Sco-Cen stars are younger than β Pic stars whose ages of ∼12Myr
have previously been derived from a kinematic traceback analysis. Our
derived age, ∼10Myr, for stars in the Lower Centaurus Crux and Upper
Centaurus Lupus subgroups of ScoCen is younger than previously
published ages based on the moving cluster method and upper
main-sequence fitting. The discrepant ages are likely due to an
incorrect (or lack of) cross-calibration between model-dependent and
model-independent age-dating methods.
Description:
Spectra with resolution λ/Δλ∼4500 of candidate
Scorpius-Centaurus members were obtained with the Double Beam
Spectrograph (DBS) on the Nasmyth-A focus of the Australian National
University's 2.3m telescope.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 140 104 *Identified members of Sco-Cen complex
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Note on table1.dat: Some (∼30) stars listed in the table were previously
identified by Mamajek et al. (2002, Cat. J/AJ/124/1670).
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See also:
B/denis : The DENIS database (DENIS Consortium, 2005)
I/284 : The USNO-B1.0 Catalog (Monet+ 2003)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
I/259 : The Tycho-2 Catalogue (Hog+ 2000)
IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999)
I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
J/other/ARA+A/42.685 : Young stars near the Sun (Zuckerman+, 2004)
J/PAZh/33/643 : Kinematics of Sco-Cen OB Association (Bobylev+, 2007)
J/A+A/448/1001 : Radial velocities of B stars in Sco-Cen (Jilinski+, 2006)
J/A+A/403/247 : Variability in the ROSAT All-Sky Survey (Fuhrmeister+, 2003)
J/AJ/124/1670 : Post-T Tauri Stars in Sco-Cen Association (Mamajek+, 2002)
J/ApJS/101/117 : UBVRIJHKLMNQ photometry in Taurus-Auriga (Kenyon+ 1995)
J/ApJS/82/117 : UBV and H-beta in Sco-Cen association (Slawson+, 1992)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Running sequence number
<[SZB2012] NNN> in Simbad
5- 7 A3 --- Group ScoCen subgroup (LCC, UCL or US) (1)
9- 22 A14 --- Name Star name
24- 25 I2 h RAh Hour of Right Ascension (J2000)
27- 28 I2 min RAm Minute of Right Ascension (J2000)
30- 34 F5.2 s RAs Second of Right Ascension (J2000)
36 A1 --- DE- Sign of the Declination
37- 38 I2 deg DEd Degree of Declination (J2000)
40- 41 I2 arcmin DEm Arcminute of Declination (J2000)
43- 46 F4.1 arcsec DEs Arcsecond of Declination (J2000)
48- 50 I3 pc Dist [35/165]? Distance (2)
52 I1 --- Num [1/4] Number of independent measurements
54- 56 I3 0.1pm W(Li) [100/580] Equivalent width (in mÅ) of
LiIλ6708 (3)
58- 62 F5.1 0.1nm W(Ha) [-60.5/1.6] Equivalent width of Hα
(negative values indicate emission) (3)
64- 68 F5.2 mag Vmag [7.86/15.35]? V magnitude
70 A1 --- r_Vmag [dpu] Origin of the V magnitude (4)
72- 75 F4.2 mag V-K [1.17/5.7]? V-K color index
77- 80 F4.2 mag B-V [0.45/1.71]? B-V color index (5)
82- 86 F5.2 --- f [-3.7/-1.9]? X-ray data [f=log(LX/Lbol)] (6)
88- 91 F4.1 km/s RV [-9.9/18]? Radial velocity
93- 95 F3.1 km/s e_RV ? Error in RV
97-101 F5.1 km/s Uvel [-14.3/-0.9]? U component of space motion
103-107 F5.1 km/s Vvel [-42.1/-10.6]? V component of space motion
109-113 F5.1 km/s Wvel [-32.4/-1]? W component of space motion
115 A1 --- f_Seq [D] Possible member of Tucana/HorA (7)
117-140 A24 --- Note Notes (8)
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Note (1): ScoCen subgroup as follows:
LCC = Lower Centaurus Crux;
UCL = Upper Centaurus Lupus;
US = Upper Scorpius and young stars in the vicinity.
Note (2): For non-Hipparcos stars, distances are photometrically estimated
based on an empirical ∼10Myr isochrone on a V-K versus MK diagram
(e.g., Figure 2 of Zuckerman & Song, 2004, Cat. J/other/ARA+A/42.685).
A typical uncertainty is about 30%.
Note (3): Average of the number of measurements indicated in column Num.
Note (4): No suffix after Vmag means Vmag come from either Hipparcos (Cat.
I/239) or Tycho-2 (Cat. I/259) and K from 2MASS (Cat. II/246).
Flag on Vmag as follows:
d = photometric data from DENIS (Cat. B/denis).
p = Our own V-band photometry and K from 2MASS (Cat. II/246).
u = Rmag from USNO (Cat. I/284) and K from 2MASS (Cat. II/246).
Note (5): Interpolated from V-K values using Kenyon & Hartmann
(1995, Cat. J/ApJS/101/117).
Note (6): From ROSAT All Sky Survey (Voges et al., 1999, Cat. IX/10). For
binaries, X-ray counts are divided according to each star's optical
brightness.
* HIP 60913 may be a member (good kinematics and W(Li)=215mÅ) with
low X-ray luminosity (f=-4.34)i
* HIP 76063 may be a member (A-type star located on zero-age main
sequence; Zuckerman & Song, 2004ApJ...613L..65Z 2004ApJ...613L..65Z).
Note (7): D = Based on UVW, HIP 84642 may instead be a Tucana/HorA member
(Table 7 of Zuckerman & Song, 2004ApJ...613L..65Z 2004ApJ...613L..65Z).
Note (8): "FS" designation indicates an X-ray variable star (Fuhrmeister &
Schmitt, 2003, Cat. J/A+A/403/247).
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History:
From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 02-Aug-2013