1999A&A...341..547D


C.D.S. - SIMBAD4 rel 1.7 - 2021.05.09CEST10:06:31

1999A&A...341..547D - Astronomy and Astrophysics, volume 341, 547-552 (1999/1-2)

Binary fraction in low-mass star forming regions: a reexamination of the possible excesses and implications.

DUCHENE G.

Abstract (from CDS):

Various surveys of low-mass binaries in star forming regions have been performed in recent years. They reached opposite conclusions concerning possible binary excesses in some of these associations. I develop a consistent method to reanalyze all these studies, so that I can compare all data consistently, and understand the previous findings. I also report the detection of five new companions to Taurus members. It appears that binary fraction in Taurus exceeds the main sequence value by a factor of 1.7 in the range 4-2000AU. The companion star fraction in this separation range is the same as the overall main sequence fraction. Ophiuchus, Chameleon, and possibly Lupus show similar excesses, although with lower confidence levels. Binaries in Ophiuchus seem to have larger flux ratios (towards faint companions) than in Taurus. It appears very unlikely that all very young star forming regions have binary excesses. The binary fraction seems to be established after ∼1Myr, but the precise nature of the difference between various regions is still unclear (overall binary fraction, orbital period distribution). It is not currently possible to put constraints on the binary formation models: higher angular resolution and larger sample sizes will be required.

Abstract Copyright:

Journal keyword(s): stars: binaries: general - stars: pre-main sequence - stars: statistics

Simbad objects: 22

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Number of rows : 22

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 Cl Melotte 22 OpC 03 47 00 +24 07.0           ~ 3077 0
2 2MASS J04034930+2610520 TT* 04 03 49.308 +26 10 52.03   15.99 14.52     M3.9 63 0
3 [HJS91] 4872 TT* 04 25 17.6698859307 +26 17 50.429311147   15.66 13.77 13.67   K9e 43 0
4 Cl Melotte 25 OpC 04 26 54.00 +15 52 00.0           ~ 2757 0
5 LDN 1521D DNe 04 27 46.5 +26 18 52           ~ 215 0
6 NAME Tau-Aur Complex SFR 04 30 +25.0           ~ 1253 0
7 V* UX Tau B TT* 04 30 03.5778750604 +18 13 49.477040697     11.51 13.33   M1Ve 65 0
8 V* HK Tau Or* 04 31 50.5722969258 +24 24 17.775488652 16.81   15.10     M0.5 303 1
9 Haro 6-37 Or* 04 46 58.97952 +17 02 38.1948           K7e+M1e 105 0
10 NAME Trapezium Cluster As* 05 35 16.5 -05 23 14           ~ 1509 1
11 NAME Flame Nebula HII 05 41 42.7 -01 54 44           ~ 693 1
12 NAME Ori B MoC 05 41 43.0 -01 54 44           ~ 1219 0
13 NGC 2024 Cl* 05 41 43 -01 50.5           ~ 1087 1
14 M 78 RNe 05 46 45.8 +00 04 45   8.0       ~ 352 0
15 NGC 2071 RNe 05 47 10 +00 18.0           ~ 616 1
16 NAME Cha 1 MoC 11 06 48 -77 18.0           ~ 1014 1
17 NAME Cha II MoC 12 54 -77.2           ~ 306 0
18 NAME Lup Cloud SFR 16 03 -38.1           ~ 559 0
19 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3165 1
20 NAME CrA Complex reg 19 15 00.0 -37 30 00           ~ 102 1
21 NAME Upper Scorpius B As* ~ ~           ~ 12 0
22 NAME Upper Scorpius A As* ~ ~           ~ 16 0

    Equat.    Gal    SGal    Ecl

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2021.05.09-10:06:31

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