J/MNRAS/402/575 Southern ultracool dwarfs in young moving groups (Clarke+, 2010)
A search for southern ultracool dwarfs in young moving groups.
Clarke J.R.A., Pinfield D.J., Galvez-ortiz M.C., Jenkins J.S.,
Burningham B., Deacon N.R., Jones H.R.A., Pokorny R.S., Barnes J.R.,
Day-Jones A.C.
<Mon. Not. R. Astron. Soc., 402, 575-588 (2010)>
=2010MNRAS.402..575C 2010MNRAS.402..575C (SIMBAD/NED BibCode)
ADC_Keywords: Associations, stellar ; Stars, dwarfs ; Stars, late-type ;
Photometry, infrared ; Proper motions
Keywords: stars: kinematics - stars: low-mass, brown dwarfs
Abstract:
We associate 132 low-mass ultracool dwarfs in the southern hemisphere
as candidate members of five moving groups (MGs) using photometric and
astrometric selection techniques. Of these objects, we present
high-resolution spectroscopy for seven candidates and combine these
with previous measurements from the literature to determine spectral
types and radial velocities. We thus constrain distance and space
motion spectroscopically, allowing the kinematic membership of the MGs
to be assessed. Possible membership of MGs has allowed ages and
metallicities to be constrained for these objects and evolutionary
models have been used to estimate their mass. We estimate that up to
∼75 of our candidate MG members should be genuine, and discuss
future work that will confirm and exploit this major new sample.
Description:
We chose to consider the five MGs assessed in Montes et al. (2001,
Cat. J/MNRAS/328/45), namely the Pleiades, Castor, Hyades, Sirius
(also known as Ursa Major) and IC2391 MGs.
By considering each MG in turn we have identified 132 objects that are
candidate members of one or more of the five MGs.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 142 132 Properties of the 132 MG candidates
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See also:
J/MNRAS/328/45 : Late-type stars members of young groups (Montes+, 2001)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 25 A25 --- Name Name
27- 31 F5.2 mag Jmag 2MASS J magnitude
33- 36 F4.2 mag e_Jmag rms uncertainty on Jmag
38- 41 F4.2 mag J-H 2MASS J-H colour index
43- 47 F5.2 mag e_J-H rms uncertainty on J-H
49- 52 F4.2 mag J-Ks 2MASS J-Ks colour index
54- 57 F4.2 mag e_J-Ks rms uncertainty on J-Ks
59- 62 F4.2 mag I-J I-J colour index (1)
64- 67 F4.2 mag e_I-J rms uncertainty on I-J
69- 73 F5.2 mag Rmag ?=- SUPERCOSMOS R magnitude (2)
75- 79 F5.1 mas/yr pmRA Proper motion along RA
81- 86 F6.1 mas/yr pmDE Proper motion along DE
88- 91 F4.1 mas/yr pm Total proper motion
93- 94 I2 pc bDist ? Lower value of photometric distance
interval (3)
95 A1 --- --- [-]
96- 98 I3 pc BDist ? Upper value of photometric distance
interval (3)
100-103 F4.1 pc Dist ? photometric Distance (3)
105-108 F4.1 pc E_Dist ? Error on Dist (upper value)
110-113 F4.1 pc e_Dist ? Error on Dist (lower value)
114 A1 --- n_Dist [defg] Note on Dist (4)
118-126 A9 --- SpType MK spectral type (5)
127 A1 --- n_SpType [fg] Note on SpType (4)
128-142 A15 --- MGmemb Potential moving groups membership (6)
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Note (1): I-band photometry is from DENIS where available, or from SuperCOSMOS.
Note (2): R-band uncertainties ∼0.3mag (Hambly, Irwin & MacGillivray,
2001MNRAS.326.1295H 2001MNRAS.326.1295H).
Note (3): Distances are parallaxes where available, or are estimated using an
MJ-(J-K) relation from our best-fitting line on the MJ versus J-K CMD with
some additional allowance for age uncertainty (see Section 3.4).
Note (4): Notes as follows:
d = Costa et al. (2005AJ....130..337C 2005AJ....130..337C)
e = Costa et al. (2006AJ....132.1234C 2006AJ....132.1234C)
f = Tinney (1996MNRAS.281..644T 1996MNRAS.281..644T)
g = SpT in literature:
Tinney (1998MNRAS.296L..42T 1998MNRAS.296L..42T), Kirkpatrick et al. (2000AJ....120..447K 2000AJ....120..447K),
Burgasser et al. (2002, Cat. J/ApJ/564/421),
Cruz & Reid (2002, Cat. J/AJ/123/2828), Gizis (2002ApJ...575..484G 2002ApJ...575..484G),
Cruz et al. (2003, Cat. J/AJ/126/2421),
Lodieu et al. (2005, Cat. J/A+A/440/1061),
Siegler et al. (2005ApJ...621.1023S 2005ApJ...621.1023S),
Burgasser & McElwain (2006AJ....131.1007B 2006AJ....131.1007B),
Basri & Reiners (2006, Cat. J/AJ/132/663) and
Phan-Bao & Bessel (2006, Cat. J/A+A/446/515)
Note (5): Spectral types are from the literature where available, or have
been determined from MJ versus spectral type relations from Dahn et al.
(2002AJ....124.1170D 2002AJ....124.1170D) for I-J≥ 2.8 and Leggett (1992) for I-J<2.8.
Note (6): The potential moving group membership for each candidate as follows:
CA = Castor
IC = IC2391
PL = Pleiades
HY = Hyades
SI = Sirius
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 24-Jul-2015