J/MNRAS/461/794 Scorpius-Centaurus K-Type Stars (Pecaut+, 2016)
The star-formation history and accretion-disk fraction among the K-type
members of the Scorpius-Centaurus OB association.
Pecaut M.J., Mamajek E.E.
<Mon. Not. R. Astron. Soc. 461, 794 (2016)>
=2016MNRAS.461..794P 2016MNRAS.461..794P (SIMBAD/NED BibCode)
ADC_Keywords: Associations, stellar ; Photometry, UBV ; Photometry, infrared ;
Proper motions
Keywords: circumstellar matter - stars: pre-main sequence -
open clusters and associations: individual: Scorpius-Centaurus,
Sco OB2, Upper Scorpius, Upper Centaurus-Lupus, Lower Centaurus-Crux
Abstract:
We present results of a spectroscopic survey for new K- and M-type
members of Scorpius-Centaurus (Sco-Cen), the nearest OB Association
(∼100-200pc). Using an X-ray, proper motion and color-magnitude
selected sample, we obtained spectra for 361 stars, for which we
report spectral classifications and Li and Ha equivalent widths. We
identified 156 new members of Sco-Cen, and recovered 51 previously
published members. We have combined these with previously known
members to form a sample of 493 solar-mass (∼0.7-1.3M[sun) members
of Sco-Cen.We investigated the star-formation history of this sample,
and re-assessed the ages of the massive main-sequence turn-off and the
G-type members in all three subgroups. We performed a census for
circumstellar disks in our sample using WISE infrared data and find a
protoplanetary disk fraction for K-type stars of 4.4+1.6-0.9% for
Upper Centaurus-Lupus and Lower Centaurus-Crux at ∼16Myr and
9.0+0.4-2.2% for Upper Scorpius at∼10Myr.
Description:
We assembled our sample of 711 candidate Sco-Cen members and collected
Johnson BV, 2MASS JHKs, WISE W1W2W3W4 photometry, positions, proper
motions and spectroscopic data collected from the literature. We
acquired low-resolution red (∼5600Å-6900Å) optical spectra from
the SMARTS 1.5m telescope in Cerro Tololo, Chile for 361 candidate
members of all three subgroups of Sco-Cen. Observations were made in
queue mode with the RC spectrograph between 2009 July and 2010
October.
For stars that meet our membership criteria, we provide kinematic
distances, extinction estimates, Teff, luminosity, and individual
mass and age estimates using a variety of published theoretical
evolutionary models. We also identify stellar members which have a
measured infrared excess, likely due to circumstellar material, and
classify these disks into evolutionary states.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 129 677 Photometry and proper motion data for candidates
in the Sco-Cen region
table3.dat 139 493 Infrared photometry and infrared excesses for
members of Sco-Cen
table4.dat 63 673 Membership properties for Sco-Cen candidates
table7.dat 146 493 Stellar properties for Sco-Cen members
table8.dat 77 180 Objects rejected as Sco-Cen members
table9.dat 88 60 Stellar parameters for Sco-Cen G-Type stars
not included in Table 7
table10.dat 69 41 Stellar parameters for Sco-Cen main sequence
turnoff stars
refs.dat 124 77 References
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See also:
I/312 : PPMX Catalog of positions and proper motions (Roeser+ 2008)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- PPMX PPMX identifier (HHMMSS.s+DDMMSS.s)
17- 32 A16 --- 2MASS 2MASS identifier (HHMMSSss+DDMMSSs)
34- 38 F5.1 mas/yr pmRA Proper motion in right ascension
39- 42 F4.1 mas/yr e_pmRA Uncertainty in Proper motion in right ascension
44- 48 F5.1 mas/yr pmDE Proper motion in declination
50- 52 F3.1 mas/yr e_pmDE Uncertainty in Proper motion in declination
54- 55 A2 --- r_pm Proper motion reference (2)
57- 62 F6.3 mag Vmag ? Johnson V band magnitude
64- 68 F5.3 mag e_Vmag ? Uncertainty in V band magnitude
70- 72 A3 --- r_Vmag ? V band magnitude reference (2)
74- 78 F5.3 mag B-V ? Johnson B-V color index
80- 84 F5.3 mag e_B-V ? Uncertainty in B-V color index
86- 88 A3 --- r_B-V ? B-V color index reference (2)
90- 95 F6.3 mag Jmag 2MASS J band magnitude
97-101 F5.3 mag e_Jmag Uncertainty in J band magnitude
103-108 F6.3 mag Hmag 2MASS H band magnitude
110-114 F5.3 mag e_Hmag Uncertainty in H band magnitude
116-121 F6.3 mag Ksmag 2MASS Ks band magnitude
123-127 F5.3 mag e_Ksmag Uncertainty in K_s band magnitude
129 A1 --- f2M [a-c] 2MASS flag (1)
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Note (1): Adopted 2MASS JHKs magnitudes are PSF-fit photometry unless
otherwise specified, as follows:
a = 2MASS JHKs aperture photometry
b = 2MASS JHKs 6x catalog
c = 2MASS H psf photometry / JKs aperture photometry
Note (2): References as follows:
PX = PPMX, 2008A&A...488..401R 2008A&A...488..401R, Cat. I/312
U4 = UCAC4, 2013AJ....145...44Z 2013AJ....145...44Z, Cat. I/322
T2 = Tycho-2, 2000A&A...355L..27H 2000A&A...355L..27H, Cat. I/259
A6 = APASS DR6 2012JAVSO..40..430H 2012JAVSO..40..430H, see Cat. II/336 (APASS DR9)
A7 = APASS DR7 2012JAVSO..40..430H 2012JAVSO..40..430H, see Cat. II/336 (APASS DR9)
HP = Hipparcos, 1997yCat.1239....0E 1997yCat.1239....0E, Cat. I/239/
W9 = Wichmann et al., 1997A&A...326..211W 1997A&A...326..211W, Cat. J/A+A/326/211
T06 = Torres et al., 2006A&A...460..695T 2006A&A...460..695T, Cat. J/A+A/460/695
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- 2MASS 2MASS identifier (HHMMSSss+DDMMSSs)
18- 35 A18 --- WISE WISE identifier (HHMMSS.ss+DDMMSS.s)
37- 42 F6.3 mag W1mag ? W1 band magnitude (1)
44- 48 F5.3 mag e_W1mag ? Uncertainty in W1 band magnitude
50- 55 F6.3 mag W2mag ? W2 band magnitude (1)
57- 61 F5.3 mag e_W2mag ? Uncertainty in W2 band magnitude
63- 68 F6.3 mag W3mag ? W3 band magnitude (1)
70- 74 F5.3 mag e_W3mag ? Uncertainty in W3 band magnitude
76- 81 F6.3 mag W4mag ? W4 band magnitude (1)
83- 87 F5.3 mag e_W4mag ? Uncertainty in W4 band magnitude
89- 94 F6.3 mag E(Ks-W1) ? Ks-W1 color index excess (1)
96-100 F5.3 mag e_E(Ks-W1) ? Uncertainty in Ks-W1 color index excess
102-107 F6.3 mag E(Ks-W2) ? Ks-W2 color index excess (1)
109-113 F5.3 mag e_E(Ks-W2) ? Uncertainty in Ks-W2 color index excess
115-120 F6.3 mag E(Ks-W3) ? Ks-W3 color index excess (1)
122-126 F5.3 mag e_E(Ks-W3) ? Uncertainty in Ks-W3 color index excess
128-133 F6.3 mag E(Ks-W4) ? Ks-W4 color index excess (1)
135-139 F5.3 mag e_E(Ks-W4) ? Uncertainty in Ks-W4 color index excess
--------------------------------------------------------------------------------
Note (1): All infrared photometry (W1, W2, W3 and W4) above is adopted from
the WISE catalog (Cutri et al., 2012yCat.2311....0C 2012yCat.2311....0C, Cat. II/311)
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 16 A16 --- 2MASS 2MASS identifier (HHMMSSss+DDMMSSs)
18- 26 A9 --- SpType ? Spectral type
28- 31 A4 --- r_SpType Spectral type reference, in refs.dat file
33- 35 I3 0.1pm EW(Li) ? Li equivalent width
37- 40 A4 --- r_EW(Li) ? Li equivalent width reference,
in refs.dat file
41- 42 A2 --- MemLi ? Li membership status
44- 45 A2 --- Mempm Proper motion Membership status
47- 48 A2 --- Memlogg ? logg membership status
50- 51 A2 --- MemHRD ? HRD membership status
53 A1 --- MemFinal Final membership status
55- 58 A4 --- r_YS Reference of the first work that identify
the star as young, in refs.dat file
60- 63 A4 --- r_SC Reference of the first work that identify the
star a member of Sco-Cen, in refs.dat file
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID Star Identifier
5- 20 A16 --- 2MASS 2MASS identifier (HHMMSSss+DDMMSSs)
22- 24 A3 --- Group Subgroup membership (LCC, UCL or US)
26- 34 A9 --- SpType Spectral type
35 A1 --- n_SpType [*] Note on SpType (1)
36- 39 A4 --- r_SpType Spectral type reference, in refs.dat file
41- 45 F5.1 0.1nm EW(Ha) ? Halpha equivalent width (2)
47- 50 A4 --- r_EW(Ha) Halpha equivalent width reference,
in refs.dat file
52- 55 F4.2 mag AV Visual extinction
57- 60 F4.2 mag e_AV ? Uncertainty in visual extinction
62- 66 F5.2 mas plxkin Kinematic parallax
68- 71 F4.2 mas e_plxkin ? Kinematic parallax
73- 77 F5.3 [K] logT Log of effective temperature
79- 83 F5.3 [K] e_logT ? Uncertainty in log of effective temperature
85- 90 F6.3 [Lsun] logL Log of Luminosity
92- 96 F5.3 [Lsun] e_logL ? Uncertainty in Log of Luminosity
98- 99 I2 Myr Age ? Stellar age from evolutionary models
101-102 A2 --- fMS [0 MS] Main sequence flag
104-106 F3.1 Msun Mass ? Stellar mass from evolutionary models
108-119 A12 --- DiskType Disk type using Espaillat et al.
(2012ApJ...747..103E 2012ApJ...747..103E) nomenclature
121-146 A26 --- Name Other stellar name
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Note (1): We report the Houk type for the star 16102888-2213477 =
HD 145208 (G5V), but internally use the Teff and BC for the equivalent
Gray type (G4.5V) in our calculations.
Note (2): EW(Ha)<0 denotes emission, EW(Ha)>0 denotes absorption.
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 16 A16 --- 2MASS 2MASS identifier (HHMMSSss+DDMMSSs)
18- 26 A9 --- SpType Spectral type
28- 30 A3 --- r_SpType Spectral type reference, in refs.dat file
32- 55 A24 --- Reason Rejection reason
57- 77 A21 --- Name Other stellar name
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Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Stellar Name
17- 32 A16 --- 2MASS 2MASS identifier (HHMMSSss+DDMMSSs)
34- 37 A4 --- SpType Spectral Type
38 A1 --- n_SpType [*] Note on SpTye (1)
39- 42 A4 --- r_SpType Spectral Type reference, in refs.dat file
44- 46 A3 --- Group Subgroup membership (LCC, UCL or US)
48- 51 F4.2 mag AV Visual extinction
53- 56 F4.2 mag e_AV ? Uncertainty in visual extinction
58- 62 F5.3 [K] logT log of effective temperature
64- 68 F5.3 [K] e_logT ? Uncertainty in log of effective temperature
70- 75 F6.3 [Lsun] logL log of luminosity
77- 81 F5.3 [Lsun] e_logL ? Uncertainty in log of luminosity
83- 84 I2 Myr Age Stellar age from evolutionary models (2)
86- 88 F3.1 Msun Mass Stellar mass from evolutionary models (2)
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Note (1): We report the Houk types for the stars HIP 78581 (G1V),
HIP 79462 (G2V) and HIP 80535 (G0V), but adopt the Teff and BC for the
equivalent Gray types in our calculations. See Table 5 for the conversions
and section 4.1 for discussion.
Table 5: Comparing Michigan spectral types to Gray MK spectral types
------------------------------------------------------------------------
SpT SpT SpT SpT SpT SpT
Houk Gray Houk Gray Houk Gray
----------------------------------------------------------------
F0V --> F1V G0V --> F9.5V K0V --> K0V
F1V --> F2V G0/1V --> F9.5V K0/1V --> K1V
F2V --> F3.5V G0/2V --> G3:V K1V --> K1.5V
F2/3V --> F3.5V G1V --> G0+V K1/2V --> K2V
F3V --> F4V G1/2V --> G0V K2V --> K2.5V
F3/5V --> F5V G2V --> G0.5V K2/3V --> K3V
F5V --> F5.5V G2/3V --> G1V K3V --> K3V
F5/6V --> F6V G3V --> G1.5V K3/4V --> K4V
F6V --> F6V G3/5V --> G4V K4V --> K4+V
F6/7V --> F6.5V G5V --> G4.5V K4/5V --> K5V
F7V --> F7.5V G5/6V --> G6V K5V --> K6-V
F7/8V --> F8V G8V --> G8.5V K5/M0V --> K7V
F8V --> F8.5V M0V --> K6.5V
F8/G0V --> F9V
----------------------------------------------------------------
Note (2): Ages and masses were estimated using the median of
2015A&A...577A..42B 2015A&A...577A..42B, 2014MNRAS.444.2525C 2014MNRAS.444.2525C, 2011A&A...533A.109T 2011A&A...533A.109T and
2008ApJS..178...89D 2008ApJS..178...89D evolutionary models.
Adopted median subgroup ages (Table 11) are preferable to uncertain individual
ages listed above.
Table 11: Adopted subgroup ages
--------------------------------------------
Method US UCL LCC
(Myr) (Myr) (Myr)
----------------------------------------------
MS Turnoff 7±2 19±2 11±2
G-Type Pre-MS 10±1 15±1 15±1
F-Type Pre-MS (a) 13±1 16±1 17±1
Adopted 10±3 16±2 15±3
--------------------------------------------
Note (a): Adopted F-type Pre-MS ages from Pecaut et al.
(2012ApJ...746..154P 2012ApJ...746..154P, Cat. J/ApJ/746/154)
--------------------------------------------
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Byte-by-byte Description of file: table10.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Object Name
14- 22 A9 --- SpType Spectral Type
24 I1 --- r_SpType [1/2] Spectral Type reference (1)
26- 28 A3 --- Group Subgroup membership (LCC, UCL or US)
30- 34 F5.3 mag AV Visual extinction
36- 40 F5.3 mag e_AV ? Uncertainty in visual extinction
42- 46 F5.3 [K] logT Log of effective temperature
48- 52 F5.3 [K] e_logT ? Uncertainty in log of effective temperature
54- 58 F5.3 [Lsun] logL log of luminosity
60- 64 F5.3 [Lsun] e_logL ? Uncertainty in log of luminosity
66 A1 --- l_Age ? Upper/Lower limit on age
68- 69 I2 Myr Age Stellar age from evolutionary models (2)
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Note (1): Spectral Type references as follows:
1 = Hiltner et al., 1969ApJ...157..313H 1969ApJ...157..313H
2 = Garrison, 1967ApJ...147.1003G 1967ApJ...147.1003G
Note (2): Ages were estimated using the Ekstroem et al. (2012A&A...537A.146E 2012A&A...537A.146E,
Cat. J/A+A/537/A146) rotating evolutionary models with solar abundances.
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- Ref Reference code
6- 24 A19 --- BibCode BibCode
26- 46 A21 --- Aut Author's name
48-124 A77 --- Com Comments
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Acknowledgements:
Mark Pecaut, mark.pecaut(at)Rockhurst.edu
(End) Mark Pecaut [Rockhurst University], Patricia Vannier [CDS] 24-Jun-2016