Stellar multiplicity and debris discs: an unbiased sample

Abstract

Circumstellar dust disks have been observed around many nearby stars. However, many stars are part of binary or multiple stellar systems. A natural question arises regarding the presence and properties of such disks in systems with more than one star. To address this, we consider a sample of 449 systems (spectral types A-M) observed with the Herschel Space Observatory as part of the DEBRIS program. We have examined the stellar multiplicity of this sample by gathering information from the literature and performing an adaptive optics imaging survey at Lick Observatory. Five new companions were revealed with our program. In total, we identify 188 (42%) binary or multiple star systems. The multiplicity of the sample is examined with regards to the detection of circumstellar disks for stars of spectral types AFGK.In general, disks are less commonly detected around binaries than single stars, though the disk frequency is comparable among A stars regardless of multiplicity. However, this sample reveals the period distribution of disk-bearing binaries is consistent with that of non-disk binaries and with comparison field samples. We find that the properties of disks in binary systems are not statistically different from those around single stars. Although the frequency of disk-bearing FGK binaries may be lower than in single star systems, the processes behind disk formation and the characteristics of these disks are comparable among both populations.

Herschel Observations of Dusty Debris Disks

“…However, Rodriguez et al (2015) found that stars with debris disks are less likely to be found in binary systems, at least in a sample of FGK stars. This may be attributable to the fact that a companion will accelerate the evolution of the dust, making a debris disk detectable for a shorter period of time, earlier on in the evolution of the system.…”

The HARPS search for southern extra-solar planets

“…The adopted uncertainty for the HARPS absolute radial velocity is 0.5 km/s; (11) Rodriguez et al (2015); (12) Ward-Duong et al (2015); (13) Kopparapu et al (2013Kopparapu et al ( , 2014; (14) Kopparapu et al (2016) activity. We also measure from the spectra the chromospheric emission in the Ca ii H&K lines, and in the Hα, Hβ, Hγ, and Na D lines (Wilson 1968;Giampapa et al 1978;Linsky et al 1982).…”

A statistically significant lack of debris discs in medium separation binary systems

“…In this paper, we compile a large sample of binary and multiple systems which have photometric measurements in the far infrared, comprising systems drawn from several sources. Our sample consists of most of the systems analysed by Trilling et al (2007), Rodriguez & Zuckerman (2012) and Rodriguez et al (2015), with the addition of systems from two unpublished Herschel surveys: OT2_gkennedy_2, which targeted visual binaries with well known orbits, and OT1_jdrake01_1, which targeted close binaries. Considering overlap between the various sources, there are 341 unique systems in the full sample.…”

“…For our analysis, we gather archival photometry for each system to create spectral energy distributions (SEDs), then model these in search of 3σ excesses in Spitzer 70 µm and Herschel 70 and 100 µm photometry characteristic of cool debris. Although broadly similar SED modelling of many of our systems has been performed in previous studies, analysing our sample as a whole rather than relying on the results of previous work removes any issues of inconsistency -for example, Trilling et al (2007) used 2σ as their excess threshold while Rodriguez et al (2015) used 3σ.…”