J/ApJ/688/377 Low-mass objects in Upper Scorpius. II. (Slesnick+, 2008)
A large-area search for low-mass objects in Upper Scorpius.
II. Age and mass distributions.
Slesnick C.L., Hillenbrand L.A., Carpenter J.M.
<Astrophys. J., 688, 377-397 (2008)>
=2008ApJ...688..377S 2008ApJ...688..377S
ADC_Keywords: Clusters, open ; Stars, pre-main sequence ; Photometry, SDSS ;
Photometry, infrared ; Equivalent widths
Keywords: open clusters and associations: individual (Upper Scorpius) -
stars: fundamental parameters - stars: low-mass, brown dwarfs -
stars: luminosity function, mass function - stars: pre-main sequence
Abstract:
We present continued results from a wide-field, ∼150°2, optical
photometric and spectroscopic survey of the northern part of the ∼5Myr
old Upper Scorpius OB association. Photometry and spectral types were
used to derive effective temperatures and luminosities and place newly
identified association members onto a theoretical Hertzsprung-Russell
diagram. From our survey, we have discovered 145 new low-mass members
of the association and determined ∼10% of these objects to be actively
accreting material from a surrounding circumstellar disk.
Description:
Drift-scan observations were taken with the Quest-2 camera on the 48
inch (1.2m) Samuel Oschin Schmidt Telescope at Palomar Observatory.
Details of the observations and data analysis are given in Paper I,
Slesnick et al. (2006, Cat. J/AJ/131/3016), and Slesnick (2007,
Ph.D. thesis, Caltech).
Moderate-resolution spectra of 105 PMS star candidates were taken with
the Double Spectrograph on the Palomar 200 inch (5.08m) telescope
during the nights of 2006 May 16-19 and June 1-2.
Additional spectra of PMS star candidates in USco were taken at CTIO
using the Hydra multifiber spectrograph on the Blanco 4m telescope
during the nights of 2005 July 24-28.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 128 145 Measured quantities for new PMS stars in USco
table2.dat 43 145 Derived quantities for new USco members
table3.dat 58 98 Measured quantities for spectroscopically
confirmed field dwarfs
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See also:
J/AJ/131/3016 : Low-mass objects in Upper Scorpius (Slesnick+, 2006)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- --- [SCH]
5- 22 A18 --- [SCH2006] Name (JHHMMSSss+DDMMSSss)
23- 25 A3 --- n_[SCH2006] [e,f ] Note on [SCH2006] (1)
27- 31 F5.2 mag gmag ?=- g magnitude
33- 37 F5.2 mag rmag ?=- r magnitude
39- 43 F5.2 mag imag ?=- i magnitude
45- 49 F5.2 mag Jmag 2MASS J magnitude
51- 55 F5.2 mag Hmag 2MASS H magnitude
57- 61 F5.2 mag Ksmag 2MASS Ks magnitude
63- 66 F4.2 --- TiO1 ?=- Strength of TiO λ7140 absorption
compared to a continuum band at 7035Å
68- 71 F4.2 --- TiO2 ?=- Strength of TiO λ8465 absorption
compared to a continuum band at 8415Å
73- 76 F4.2 --- Na1 ?=- Strength of the NaI doublet at 8189Å
compared to a continuum band at 8150Å
78- 82 A5 --- SpT MK spectral type (2)
84- 89 F6.1 0.1nm EWHa Hα equivalent width
91-121 A31 --- Name2 Other name
124-127 A4 --- SpT2 Other MK spectral type associated to Name2
128 A1 --- r_SpT2 [dghij] Reference to Name2 and SpT2 (3)
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Note (1): Notes as follows:
e = Two targets observed during the first spectroscopic observing
run before the final photometric calibrations were finished do
not have calibrated r, i magnitudes.
f = Star identified as a member of USco in Paper I, J/AJ/131/3016
Note (2): Spectral type errors are ±0.5 for M subclasses.
Note (3): References as follows:
d = Martin et al. (2004AJ....127..449M 2004AJ....127..449M)
g = Ardila et al. (2000, Cat. J/AJ/120/479)
h = Preibisch et al. (2002, Cat. J/AJ/124/404)
i = Barsony et al. (1997, Cat. J/ApJS/112/109)
j = Wilking et al. (1987AJ.....94..106W 1987AJ.....94..106W)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- --- [SCH]
5- 22 A18 --- [SCH2006] Name (JHHMMSSss+DDMMSSss)
24- 27 F4.2 [K] logTe Effective temperature
29- 33 F5.2 [solLum] logL Luminosity
35- 38 F4.2 [yr] logAge ?=- Age (1)
40- 43 F4.2 solMass Mass Mass (1)
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Note (1): Masses and ages derived from the model tracks and isochrones of
D'Antona & Mazzitelli (1997MmSAI..68..807D 1997MmSAI..68..807D).
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- --- [SCH]
5- 22 A18 --- [SCH2006] Name (JHHMMSSss+DDMMSSss)
24- 28 F5.2 mag gmag ?=- g magnitude
30- 34 F5.2 mag rmag r magnitude
36- 40 F5.2 mag imag i magnitude
42- 46 F5.2 mag Jmag 2MASS J magnitude
48- 52 F5.2 mag Hmag 2MASS H magnitude
54- 58 F5.2 mag Ksmag 2MASS Ks magnitude
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History:
From electronic version of the journal
References:
Slesnick et al., Paper I 2006AJ....131.3016S 2006AJ....131.3016S (Cat. J/AJ/131/3016)
(End) Patricia Vannier [CDS] 16-Nov-2009