The search for low-mass companions of B stars in the Carina Nebula Cluster Trumpler 16

Nancy Remage Evans, Kathleen D Eastwood, Marc Gagné, Leisa Townsley, Patrick Broos, Scott Wolk, Yal Nazé, Michael Corcoran, Lida Oskinova, Anthony F J Moffat, Junfeng Wang, Nolan R. Walborn

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

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 η 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 Ȯ 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 Ȯ) primaries, such as would be found by random pairing from the initial mass function.

Original languageEnglish (US)
Article number13
JournalAstrophysical Journal, Supplement Series
Volume194
Issue number1
DOIs
StatePublished - May 2011

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B stars
nebulae
proper motion
x rays
late stars
lists
stars
companion stars
main sequence stars
completeness
mass ratios
automobile
luminosity
probe
color

Keywords

  • open clusters and associations: individual (Trumpler 16)
  • stars: massive

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

The search for low-mass companions of B stars in the Carina Nebula Cluster Trumpler 16. / Evans, Nancy Remage; Eastwood, Kathleen D; Gagné, Marc; Townsley, Leisa; Broos, Patrick; Wolk, Scott; Nazé, Yal; Corcoran, Michael; Oskinova, Lida; Moffat, Anthony F J; Wang, Junfeng; Walborn, Nolan R.

In: Astrophysical Journal, Supplement Series, Vol. 194, No. 1, 13, 05.2011.

Research output: Contribution to journalArticle

Evans, NR, Eastwood, KD, Gagné, M, Townsley, L, Broos, P, Wolk, S, Nazé, Y, Corcoran, M, Oskinova, L, Moffat, AFJ, Wang, J & Walborn, NR 2011, 'The search for low-mass companions of B stars in the Carina Nebula Cluster Trumpler 16', Astrophysical Journal, Supplement Series, vol. 194, no. 1, 13. https://doi.org/10.1088/0067-0049/194/1/13
Evans, Nancy Remage ; Eastwood, Kathleen D ; Gagné, Marc ; Townsley, Leisa ; Broos, Patrick ; Wolk, Scott ; Nazé, Yal ; Corcoran, Michael ; Oskinova, Lida ; Moffat, Anthony F J ; Wang, Junfeng ; Walborn, Nolan R. / The search for low-mass companions of B stars in the Carina Nebula Cluster Trumpler 16. In: Astrophysical Journal, Supplement Series. 2011 ; Vol. 194, No. 1.
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