THE SEARCH FOR LOW-MASS COMPANIONS OF B STARS IN THE CARINA NEBULA CLUSTER TRUMPLER 16

Journal Article · Sun May 01 04:00:00 EDT 2011 · Astrophysical Journal, Supplement Series

DOI:https://doi.org/10.1088/0067-0049/194/1/13· OSTI ID:21562678

Remage Evans, Nancy ^[1]; DeGioia-Eastwood, Kathleen ^[2]; Gagne, Marc ^[3]; Townsley, Leisa; Broos, Patrick ^[4]; Wolk, Scott ^[5]; Naze, Yael ^[6]; Corcoran, Michael ^[7]; Oskinova, Lida ^[8]; Moffat, Anthony F. J. ^[9]; Junfeng, Wang ^[10]

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1. Smithsonian Astrophysical Observatory, MS 4, 60 Garden Street, Cambridge, MA 02138 (United States)
2. Department of Physics and Astronomy, Northern Arizona University, Box 6010, Flagstaff, AZ 86011-6010 (United States)
3. Department of Geology and Astronomy, West Chester University, West Chester, PA 19883 (United States)
4. Department of Astronomy and Astrophysics, 525 Davey Laboratory, Pennsylvania State University, University Park, PA 16802 (United States)
5. Smithsonian Astrophysical Observatory, MS 70, 60 Garden Street, Cambridge, MA 02138 (United States)
6. GAPHE Departement AGO, Universite de Liege, Allee du 6 Aout 17, Bat. B5C, B4000-Liege (Belgium)
7. NASA's Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States)
8. Institute for Physics and Astronomy, University Potsdam, 14476 Potsdam (Germany)
9. Dept. de Physique, Univ. de Montreal, CP 6128 Succ. A. Centre-Ville, Montreal, QC H3C 3J7 (Canada)
10. Smithsonian Astrophysical Observatory, MS 06, 60 Garden Street, Cambridge, MA 02138 (United States)

We have developed lists of likely B3-A0 stars (called 'late B' stars) in the young cluster Trumpler 16. The following criteria were used: location within 3' of {eta} Car, an appropriate V and B - V combination, and proper motion (where available). Color and magnitude cuts have been made assuming an E(B - V) = 0.55 mag {+-} 0.1, which is a good approximation close to the center of Trumpler 16. These lists have been cross-correlated with X-ray sources found in the Chandra Carina Complex Project. Previous studies have shown that only very rarely (if at all) do late main-sequence B stars produce X-rays. We present evidence that the X-ray-detected sources are binaries with low-mass companions, since stars less massive than 1.4 M{sub sun} are strong X-ray sources at the age of the cluster. Both the median X-ray energies and X-ray luminosities of these sources are in good agreement with values for typical low-mass coronal X-ray sources. We find that 39% of the late B stars based on a list with proper motions have low-mass companions. Similarly, 32% of a sample without proper motions have low-mass companions. We discuss the X-ray detection completeness. These results on low-mass companions of intermediate-mass stars are complementary to spectroscopic and interferometric results and probe new parameter space of low-mass companions at all separations. They do not support a steeply rising distribution of mass ratios to low masses for intermediate-mass (5 M{sub sun}) primaries, such as would be found by random pairing from the initial mass function.

• OSTI ID: 21562678
• Journal Information: Astrophysical Journal, Supplement Series, Journal Name: Astrophysical Journal, Supplement Series Journal Issue: 1 Vol. 194; ISSN 0067-0049; ISSN APJSA2
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COLOR
DETECTION
LUMINOSITY
MASS
MOTION
NEBULAE
OPTICAL PROPERTIES
ORGANOLEPTIC PROPERTIES
PHYSICAL PROPERTIES
PROPER MOTION
RADIATION DETECTION
RADIATION SOURCES
STARS
X-RAY DETECTION
X-RAY SOURCES