Аннотация
We compile observations of early-type binaries identified via spectroscopy,
eclipses, long-baseline interferometry, sparse aperture masking, adaptive
optics, lucky imaging, and common proper motion. We combine the samples from
the various surveys and correct for their respective selection effects to
determine a comprehensive nature of the intrinsic multiplicity statistics of
O-type and B-type stars. We find the properties of companions to massive stars
differ among three regimes. First, at short orbital periods P < 20 days
(separations a < 0.4 AU), the binaries have small eccentricities e < 0.4, favor
modest mass ratios $łangle$q$\rangle$ = 0.5, and exhibit a small excess of
twins q > 0.95. Second, the companion frequency peaks at intermediate periods
log P (days) = 3.5 (a = 10 AU), where the binaries have mass ratios weighted
toward small values q = 0.2-0.3 and follow a Maxwellian "thermal" eccentricity
distribution. Finally, companions with long orbital periods log P (days) =
5.5-7.5 (a = 200-5,000 AU) are outer tertiary components in hierarchical
triples, and have a mass ratio distribution across q = 0.1-1.0 that is nearly
consistent with random pairings drawn from the initial mass function. We
discuss these companion distributions and properties in the context of binary
star formation and evolution. We also reanalyze the binary statistics of
solar-type primaries, taking into account that (30$\pm$10)% of single-lined
spectroscopic binaries likely contain white dwarf companions instead of
low-mass stellar secondaries. The mean frequency of stellar companions with q >
0.1 per primary increases from 0.48$\pm$0.04 for solar-type primaries to
2.1$\pm$0.3 for O-type primaries. We fit joint probability density functions
f(M$_1$,q,P,e) $\neq$ f(M$_1$)f(q)f(P)f(e) to the corrected distributions,
which can be incorporated into binary population synthesis studies.
Описание
Mind your Ps and Qs: the Interrelation between Period (P) and Mass-ratio
(Q) Distributions of Binary Stars
Линки и ресурсы
тэги