J/A+AS/119/221 UBVRI photometry of stars in Berkeley 86 (Deeg+, 1996)
Deep CCD photometry and the initial mass function of the core of the OB cluster
Berkeley 86.
Deeg H.J., Ninkov Z.
<Astron. Astrophys. Suppl. Ser. 119, 221 (1996)>
=1996A&AS..119..221D 1996A&AS..119..221D (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Photometry, CCD
Keywords: stars: luminosity function, mass function -
open clusters and associations: individual: Bky 86
Description:
Based on photometry of deep CCD frames of the central region of the OB
cluster Berkeley 86, we derive the cluster mass function. The absence
of current star formation, and the cluster's young age of about 6Myrs,
leads to the conclusion that the initial mass function (IMF) and the
current mass function are identical for stars with m<10m☉. In
the range of 1.2-20m☉, an IMF with a slope of {GAMMA}=-1.3±0.3
is found. This value agrees well with other recent determinations of
young clusters IMFs which are close to the classical Salpeter IMF with
{GAMMA}=-1.35. Sections of the IMF of Berkeley 86 that are
significantly steeper, or flatter, are most likely the result of a dip
in the star's mass distribution in the range of 3.5-10m☉.
Similar dips may have led to steep IMFs over narrow mass ranges, as
reported in the literature for some other clusters. No sign for a low
mass turn-over in the IMF of Berkeley 86 is found for masses extending
down to 0.85 m☉.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1 88 544 UBVRI photometry of 544 stars in Bky86
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Byte-by-byte Description of file: table1
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID [1,544]+ ID number of stars in this paper
5- 9 A5 --- Forbes-ID ID number of stars in Forbes et al.
(1992AJ....103..916F 1992AJ....103..916F) (1)
11- 18 F8.4 deg RAdeg += Right Ascencion (J2000) (2)
20- 26 F7.4 deg DEdeg Declination (J2000) (2)
28- 32 F5.2 mag Vmag V magnitude
34- 37 F4.2 mag e_Vmag rms uncertainty on Vmag
39- 43 F5.2 mag U-B ? U-B color index
45- 48 F4.2 mag e_U-B ? rms uncertainty on U-B
50- 53 F4.2 mag B-V ? B-V color index
55- 58 F4.2 mag e_B-V ? rms uncertainty on B-V
60- 63 F4.2 mag V-R V-R color index
65- 68 F4.2 mag e_V-R rms uncertainty on V-R
70- 73 F4.2 mag R-I R-I color index
75- 78 F4.2 mag e_R-I rms uncertainty on R-I
80- 83 F4.2 mag E(B-V) E(B-V) extinction
85- 88 F4.2 [solMass] logM ? log mass of cluster-members;
9.99= non-member; only entries for stars
with V<18.5
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Note (1): ID 162 = Forbes-ID 1 is also HD228969
Note (2): Precision is about 1 arcsec.
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Courtesy: Hans-Jorg Deeg
References:
Forbes, D. et al., 1992, AJ, 103, 916 =1992AJ....103..916F 1992AJ....103..916F
(End) Patricia Bauer [CDS] 25-Apr-1996