J/A+A/400/891 IZ photometry of Pleiades brown dwarfs (Moraux+, 2003)
Brown dwarfs in the Pleiades cluster: clues to the substellar mass function.
Moraux E., Bouvier J., Stauffer J.R., Cuillandre J.-C.
<Astron. Astrophys. 400, 891 (2003)>
=2003A&A...400..891M 2003A&A...400..891M
ADC_Keywords: Clusters, open ; Stars, dwarfs ; Photometry ; Surveys
Keywords: stars: low-mass, brown dwarfs ; stars: mass function ;
open clusters and associations: individual: Pleiades
Abstract:
We present the results of a 6.4 square degrees imaging survey of the
Pleiades cluster in the I and Z-bands. The survey extends up to 3°
from the cluster center and is 90% complete down to I~=22. It covers a
mass range from 0.03M☉ to 0.48M☉ and yields 40 brown dwarf
candidates (BDCs) of which 29 are new. The spatial distribution of
BDCs is fitted by a King profile in order to estimate the cluster
substellar core radius. The Pleiades mass function is then derived
across the stellar-substellar boundary and we find that, between
0.03M☉ and 0.48M☉, it is well represented by a single
power-law, dN/dM∝M-α, with an index alpha=0.60±0.11.
Over a larger mass domain, however, from 0.03M☉ to 10M☉,
the mass function is better fitted by a log-normal function. We
estimate that brown dwarfs represent about 25% of the cluster
population which nevertheless makes up less than 1.5% of the cluster
mass. The early dynamical evolution of the cluster appears to have had
little effect on its present mass distribution at an age of 120Myr.
Comparison between the Pleiades mass function and the Galactic field
mass function suggests that apparent differences may be mostly due to
unresolved binary systems.
Description:
The I and Z observations were made using the CFH12K mosaic camera at
the prime focus of the Canada-France-Hawaii telescope, from December
17 to 19, 2000. For each star I-magnitude, color I-Z and equatorial
coordinates (J2000) are given.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 45 109 I and Z photometry of Pleiades star members
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See also:
J/A+A/323/139 : K magnitude of Pleiades low-mass binaries (Bouvier+ 1997)
J/A+A/335/183 : Pleiades low-mass stars rotational velocities (Queloz+ 1998)
J/A+AS/100/607 : Pleiades very low-mass proper motion members (Hambly+ 1993)
J/MNRAS/313/347 : Pleiades low-mass stars and brown dwarfs (Pinfield+, 2000)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Sequential number
7- 11 F5.2 mag Imag Mould I magnitude (822.3nm)
15- 18 F4.2 mag I-Z I-Z color index
22 I1 h RAh Right ascension (J2000.0)
24- 25 I2 min RAm Right ascension (J2000.0)
27- 31 F5.2 s RAs Right ascension (J2000.0)
34 A1 --- DE- Declination sign (J2000.0)
35- 36 I2 deg DEd Declination (J2000.0)
38- 39 I2 arcmin DEm Declination (J2000.0)
41- 45 F5.2 arcsec DEs Declination (J2000.0)
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Acknowledgements: Estelle Moraux
(End) Patricia Bauer [CDS] 11-Mar-2003