Nancy Remage Evans, Kathleen DeGioia-Eastwood, Marc Gagne, Leisa Townsley, Patrick S. Broos, Scott J. Wolk, Yael Naze, Michael Corcoran, Lidia M. Oskinova, Anthony F. J. Moffat, Junfeng Wang, Nolan R. Walborn
- 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-circle dot 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.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-circle dot 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-circle dot) primaries, such as would be found by random pairing from the initial mass function.…
MetadatenAuthor details: | Nancy Remage Evans, Kathleen DeGioia-Eastwood, Marc Gagne, Leisa Townsley, Patrick S. Broos, Scott J. Wolk, Yael Naze, Michael Corcoran, Lidia M. OskinovaORCiDGND, Anthony F. J. Moffat, Junfeng Wang, Nolan R. Walborn |
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DOI: | https://doi.org/10.1088/0067-0049/194/1/13 |
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ISSN: | 0067-0049 |
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Title of parent work (English): | The astrophysical journal : an international review of spectroscopy and astronomical physics ; Supplement series |
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Publisher: | IOP Publ. Ltd. |
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Place of publishing: | Bristol |
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Publication type: | Article |
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Language: | English |
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Year of first publication: | 2011 |
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Publication year: | 2011 |
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Release date: | 2017/03/26 |
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Tag: | open clusters and associations: individual (Trumpler 16); stars: massive |
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Volume: | 194 |
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Issue: | 1 |
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Number of pages: | 9 |
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Funding institution: | Chandra X-ray Center NASA [NAS8-03060]; Chandra [GO8-9131X]; ACIS
Instrument Team [SV4-74018]; NASA [NAS8-03060]; NSERC (Canada); FQRNT
(Quebec); Fonds National de la Recherche Scientifique (Belgium); PRODEX
XMM; Action de Recherche Concertee (CFWB Academie Wallonie Europe);
STScI |
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Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
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Peer review: | Referiert |
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