The Volume-limited A-Star (VAST) survey – I. Companions and the unexpected X-ray detection of B6–A7 stars

By R. J. Rosa, J. Bulger, J. Patience, Benn J. Leland, B. Macintosh, A. Schneider, Inseok Song, C. Marois, J. Graham, M. Bessell and 1 more. 2011

217 citations recorded by the source corpus.

With an adaptive optics imaging survey of 148 B6―A7 stars, we have tested the hypothesis that unresolved lower mass companions are the source of the unexpected X-ray detections of stars in this spectral type range. The sample is composed of 63 stars detected in X-rays within the ROSAT All Sky Survey and 85 stars that form a control sample; both subsets have the same restricted distribution of spectral type, age, X-ray sensitivity and separation coverage. A total of 68 companion candidates are resolved with separations ranging from 0.3 to 26.2 arcsec, with 23 new detections. The multiple star frequency of the X-ray sample based on companions resolved within the ROSAT error ellipse is found to be 43 +6 ―6 per cent. The corresponding control sample multiple star frequency is three times lower at 12 +4 ―3 per cent - a difference of 31 ± 7 per cent. These results are presented in the first of a series of papers based on our Volume-limited A-Star (VAST) survey - a comprehensive study of the multiplicity of A-type stars.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/54927b12a79b8a5e7560eaea8b2d421143ef0809

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The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. B. Bowler
2. R. Doyon
3. B. Macintosh
4. C. Marois
5. M. Moe
6. Inseok Song
7. M. Bessell
8. R. Di Stefano

In Atomic and Molecular Physics, and Optics

1. B. Macintosh
2. Inseok Song
3. C. Marois
4. R. Doyon
5. Luca Casagrande
6. Eric Mamajek
7. D. VandenBerg
8. C. Willmer

In Instrumentation

1. B. Macintosh
2. C. Marois
3. R. Doyon
4. A. Berkeley
5. Institut de Plan'etologie et d'Astrophysique de Grenoble
6. Harvard-Smithsonian Cfa
7. C. Kulesa
8. K. Ward-Duong

Citations in the corpus

• Searching for faint companions with VLTI/PIONIER - II. 92 main sequence stars from the Exozodi survey (2014, background): “Only recently have large-scale, dedicated (AOassisted) surveys been conducted, including most notably the VAST survey (De Rosa et al. 2011).”
• The M-dwarfs in Multiples (MinMs) survey – I. Stellar multiplicity among low-mass stars within 15 pc (2015, methodology): “…the flux ratio between the primary and companion allowed us to derive the magnitude difference of the two objects; any stars unresolved in the 2MASS photometry (with ∆m < 4 and ρ < 10 arcsec) were corrected for the individual contributions from each of the stellar components (De Rosa et al. 2011).”
• Stellar Multiplicity (2013, background): “The most thorough search for visual companions to A stars is the ongoing VAST survey (De Rosa et al. 2011).”
• The VAST Survey - III. The multiplicity of A-type stars within 75 pc (2013, methodology): “Of the 113 identified companions within the AO observations, 51 were newly resolved as a part of the VAST survey (De Rosa et al. 2011, 2012), 33 of which are presented for the first time within this paper.”
• Mind Your Ps and Qs: The Interrelation between Period (P) and Mass-ratio (Q) Distributions of Binary Stars (2016, background): “Indeed, (43± 6)% of X-ray bright late-B and early-A MS stars were resolved with adaptive optics to have low-mass companions at angular separations ρ = 0.3′′ - 26′′ (De Rosa et al. 2011), i.e. 4.7 . logP (days) .”