Abstract
We present the first multiepoch radial velocity study of embedded young massive stars using near-infrared spectra obtained with ISAAC mounted at the ESO Very Large Telescope, with the aim of detecting massive binaries. Our 16 targets are located in high-mass star-forming regions, and many of them are associated with known ultracompact H II regions, whose young age ensures that dynamic evolution of the clusters did not influence the intrinsic binarity rate. We identify two stars with about 90 km s-1 velocity differences between two epochs, proving the presence of close massive binaries. The fact that two out of the 16 observed stars are binary systems suggests that at least 20% of the young massive stars are formed in close multiple systems, but may also be consistent with most, if not all, young massive stars being binaries. In addition, we show that the radial velocity dispersion of the full sample is about 35 km s-1, significantly larger than our estimated uncertainty (25 km s-1). This finding is consistent with similar measurements of the young massive cluster 30 Dor, which might have a high intrinsic binary rate. Furthermore, we argue that virial cluster masses derived from the radial velocity dispersion of young massive stars may intrinsically overestimate the cluster mass due to the presence of binaries.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 484-491 |
| Number of pages | 8 |
| Journal | Astrophysical Journal |
| Volume | 655 |
| Issue number | 1 I |
| DOIs | |
| State | Published - Jan 20 2007 |
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Keywords
- Binaries: close
- Binaries: spectroscopic
- Infrared: stars
- Stars: early-type
- Stars: formation
ASJC Scopus subject areas
- Space and Planetary Science
Cite this
Massive binaries in high-mass star-forming regions : A multiepoch radial velocity survey of embedded O stars. / Apai, Daniel; Bik, Arjan; Kaper, Lex; Henning, Thomas; Zinnecker, Hans.
In: Astrophysical Journal, Vol. 655, No. 1 I, 20.01.2007, p. 484-491.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Massive binaries in high-mass star-forming regions
T2 - A multiepoch radial velocity survey of embedded O stars
AU - Apai, Daniel
AU - Bik, Arjan
AU - Kaper, Lex
AU - Henning, Thomas
AU - Zinnecker, Hans
PY - 2007/1/20
Y1 - 2007/1/20
N2 - We present the first multiepoch radial velocity study of embedded young massive stars using near-infrared spectra obtained with ISAAC mounted at the ESO Very Large Telescope, with the aim of detecting massive binaries. Our 16 targets are located in high-mass star-forming regions, and many of them are associated with known ultracompact H II regions, whose young age ensures that dynamic evolution of the clusters did not influence the intrinsic binarity rate. We identify two stars with about 90 km s-1 velocity differences between two epochs, proving the presence of close massive binaries. The fact that two out of the 16 observed stars are binary systems suggests that at least 20% of the young massive stars are formed in close multiple systems, but may also be consistent with most, if not all, young massive stars being binaries. In addition, we show that the radial velocity dispersion of the full sample is about 35 km s-1, significantly larger than our estimated uncertainty (25 km s-1). This finding is consistent with similar measurements of the young massive cluster 30 Dor, which might have a high intrinsic binary rate. Furthermore, we argue that virial cluster masses derived from the radial velocity dispersion of young massive stars may intrinsically overestimate the cluster mass due to the presence of binaries.
AB - We present the first multiepoch radial velocity study of embedded young massive stars using near-infrared spectra obtained with ISAAC mounted at the ESO Very Large Telescope, with the aim of detecting massive binaries. Our 16 targets are located in high-mass star-forming regions, and many of them are associated with known ultracompact H II regions, whose young age ensures that dynamic evolution of the clusters did not influence the intrinsic binarity rate. We identify two stars with about 90 km s-1 velocity differences between two epochs, proving the presence of close massive binaries. The fact that two out of the 16 observed stars are binary systems suggests that at least 20% of the young massive stars are formed in close multiple systems, but may also be consistent with most, if not all, young massive stars being binaries. In addition, we show that the radial velocity dispersion of the full sample is about 35 km s-1, significantly larger than our estimated uncertainty (25 km s-1). This finding is consistent with similar measurements of the young massive cluster 30 Dor, which might have a high intrinsic binary rate. Furthermore, we argue that virial cluster masses derived from the radial velocity dispersion of young massive stars may intrinsically overestimate the cluster mass due to the presence of binaries.
KW - Binaries: close
KW - Binaries: spectroscopic
KW - Infrared: stars
KW - Stars: early-type
KW - Stars: formation
UR - http://www.scopus.com/inward/record.url?scp=33846892805&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33846892805&partnerID=8YFLogxK
U2 - 10.1086/509705
DO - 10.1086/509705
M3 - Article
VL - 655
SP - 484
EP - 491
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1 I
ER -