J/ApJ/746/154 Improved kinematic parallaxes for Sco-Cen members (Pecaut+, 2012)
A revised age for upper Scorpius and the star formation history among the
F-type members of the Scorpius-Centaurus OB association.
Pecaut M.J., Mamajek E.E., Bubar E.J.
<Astrophys. J., 746, 154 (2012)>
=2012ApJ...746..154P 2012ApJ...746..154P
ADC_Keywords: Parallaxes, spectroscopic ; Spectral types ; Stars, masses ;
Associations, stellar ; Stars, F-type ; Extinction
Keywords: circumstellar matter - Hertzsprung-Russell and C-M diagrams -
open clusters and associations: individual (Scorpius-Centaurus) -
stars: individual (Antares, 1RXS J160930.3-210459) -
stars: pre-main sequence
Abstract:
We present an analysis of the ages and star formation history of the
F-type stars in the Upper Scorpius (US), Upper Centaurus-Lupus (UCL),
and Lower Centaurus-Crux (LCC) subgroups of Scorpius-Centaurus
(Sco-Cen), the nearest OB association. Our parent sample is the
kinematically selected Hipparcos sample of de Zeeuw et al. (1999,
Cat. J/AJ/117/354), restricted to the 138 F-type members. We have
obtained classification-resolution optical spectra and have also
determined the spectroscopic accretion disk fraction. With Hipparcos
and 2MASS photometry, we estimate the reddening and extinction for
each star and place the candidate members on a theoretical H-R
diagram. For each subgroup we construct empirical isochrones and
compare to published evolutionary tracks.
Description:
Low-resolution blue (∼3700Å-5200Å) and red (∼5600Å-6900Å)
optical spectra were obtained from the SMARTS 1.5m telescope at Cerro
Tololo Inter-American Observatory (CTIO). Observations were made in
queue mode with the RC spectrograph between 2009 February and 2009
December.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 106 138 Input observables for Sco-Cen candidate members
table4.dat 112 124 Stellar parameters for F-type Sco-Cen members
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See also:
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
I/259 : The Tycho-2 Catalogue (Hog+ 2000)
J/AJ/144/8 : Spectroscopy of ∼100 G/K/M-type Sco-Cen members (Song+, 2012)
J/ApJ/745/56 : Upper Sco members rotational velocities (Dahm+, 2012)
J/A+A/527/A24 : Spectra of low-mass stars in Upper Sco (Lodieu+, 2011)
J/A+A/504/981 : Proper motions of cool stars in Upper Sco OB (Bouy+, 2009)
J/PAZh/33/643 : Kinematics of Sco-Cen OB Association (Bobylev+, 2007)
J/MNRAS/373/95 : ZYJHK survey of Upper Sco association (Lodieu+, 2006)
J/AJ/121/1040 : PMS members of upper Sco OB association (Preibisch+, 2001)
J/AJ/117/354 : OB associations from Hipparcos (de Zeeuw+, 1999)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- HIP HIP number
7- 9 A3 --- Grp Subgroup (LCC, UCL, US) (G1)
11- 26 A16 --- 2MASS 2MASS identification (HHMMSSss+DDMMSSs)
28- 33 F6.2 mas/yr pmRA [-43.28,-6] Proper motion along RA
(µα*) (1)
35- 38 F4.2 mas/yr e_pmRA [0.42,2.57] pmRA uncertainty (1)
40- 45 F6.2 mas/yr pmDE [-35.2,4.41] Proper motion along DEC (1)
47- 50 F4.2 mas/yr e_pmDE [0.33,2.3] pmDE uncertainty (1)
52- 56 F5.2 mag Vmag [6.62,10.57] Hipparcos V-band magnitude
58- 62 F5.3 mag B-V [0.23,0.755] Hipparcos B-V color index
64- 68 F5.3 mag e_B-V [0.001,0.495] B-V uncertainty
70- 74 F5.3 mag Jmag [5.688,9.836] 2MASS J-band magnitude
76- 80 F5.3 mag e_Jmag [0.018,0.056] Jmag uncertainty
82- 86 F5.3 mag Hmag [5.459,9.729] 2MASS H-band magnitude
88- 92 F5.3 mag e_Hmag [0.021,0.069] Hmag uncertainty
94- 98 F5.3 mag Ksmag [5.326,9.653] 2MASS Ks-band magnitude
100-104 F5.3 mag e_Ksmag [0.016,0.038] Ksmag uncertainty
106 A1 --- r_pm [HT] PM reference (1)
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Note (1): We have taken proper motion data, used to calculate a
kinematically improved parallax (more on this in Section 4.3) from
both the revised Hipparcos data ("H", van Leeuwen 2007, Cat. I/311)
and the Tycho-2 ("T" Hog et al. 2000, Cat. I/259) catalogs. We used
revised Hipparcos data if the fit obtained is that for a single star
(i.e., a five-parameter solution with no peculiarities). Otherwise we
use the long-baseline proper motions from the Tycho-2 catalog.
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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- 5 I5 --- HIP HIP number
7- 9 A3 --- Grp Subgroup (LCC, UCL, US) (G1)
11- 16 A6 --- SpT MK spectral type from this work (section 4.1)
18- 22 F5.2 mas pKin [4.6,12.7] Kinematic parallax (section 4.3)
24- 27 F4.2 mas e_pKin [0.38,0.96] pKin uncertainty
29- 32 F4.1 0.1nm EWHa [-1.9,6.7] Hα equivalent width
34- 37 F4.2 mag Av [0,1] Extinction (section 4.2)
39- 42 F4.2 mag e_Av [0.01,0.4] Av uncertainty
44- 48 F5.3 [K] logTe [3.781,3.872] Log of effective temperature
50- 54 F5.3 [K] e_logTe [0.005,0.017] logTe uncertainty (1)
56- 59 F4.2 [Lsun] logL [0.23,1.18] Luminosity (log(L/L☉))
61- 64 F4.2 [Lsun] e_logL [0.05,0.18] logL uncertainty
66- 68 F3.1 Msun M1 [1.1,2] Mass from D08 (2)
70 A1 --- f_M1 [a] Assumed age (15Myr) (3)
72 A1 --- l_Age1 Limit flag on Age (4)
74- 75 I2 Myr Age1 [5,32] Age from D08 (2)
77- 79 F3.1 Msun M2 [1.2,2] Mass (2)
81 A1 --- f_M2 [a] Assumed age (15Myr) (3)
83 A1 --- l_Age2 Limit flag on Age2 (4)
85- 86 I2 Myr Age2 [5,83]? Age (2)
88- 90 F3.1 Msun M3 [1.3,2] Mass (2)
92 A1 --- f_M3 [ab] Assumed age (15 or 10Myr) (3)
94 A1 --- l_Age3 Limit flag on Age3 (4)
96- 97 I2 Myr Age3 [7,62]? Age (2)
99-101 F3.1 --- M4 [1.2,2] Mass (2)
103 A1 --- f_M4 [ab] Assumed age (15 or 10Myr) (3)
105 A1 --- l_Age4 Limit flag on Age4 (4)
107-108 I2 --- Age4 [5,39]? Age (2)
110-112 F3.1 Msun M [1.2,2] Median mass (5)
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Note (1): Uncertainties in log(Teff) are calculated with a spectral type
uncertainty of 1 subtype.
Note (2): Reference as below:
D08 = (1) Dotter et al. 2008ApJS..178...89D 2008ApJS..178...89D
YY04 = (2) Demarque et al. 2004ApJS..155..667D 2004ApJS..155..667D
S00 = (3) Siess et al. 2000A&A...358..593S 2000A&A...358..593S
DM97 = (4) D'Antona & Mazzitelli 1997MmSAI..68..807D 1997MmSAI..68..807D
Note (3): Flag as follows:
a = Mass was derived assuming a 15 Myr age.
b = Mass was derived assuming a 10 Myr age.
Note (4): In cases where the H-R diagram position was too close to the main
sequence to yield a unique age, we provide upper limits (denoted by <)
based on the 2σ upper limit on the luminosity.
Note (5): We have provided the median mass of all evolutionary tracks as
the preferred mass for each member. Given the sizes of the
observational uncertainties, it is preferable to adopt the median
subgroup ages rather than these individual isochronal ages.
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Global notes:
Note (G1): Sco-Cen consists of three subgroups: Upper Scorpius ("US"),
Upper Centaurus-Lupus ("UCL"), and Lower Centaurus-Crux ("LCC"), with
mean distances of 145pc, 140pc, and 118pc, respectively (de Zeeuw et
al. 1999, Cat. J/AJ/117/354).
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 07-Aug-2013