The Close Companion Mass-Ratio Distribution of Intermediate-Mass Stars
K. Gullikson, A. Kraus, and S. Dodson-Robinson. (2016)cite arxiv:1604.06456Comment: Accepted to the Astronomical Journal. 26 pages, 7 figures, 5 tables. The code to replicate the analysis is available at https://github.com/kgullikson88/BinaryInference All of the spectra used in this work, as well as a significant portion of the intermediate data products and MCMC samples are available at: https://zenodo.org/record/48073 and https://zenodo.org/record/46482.
Abstract
Binary stars and higher-order multiple systems are an ubiquitous outcome of
star formation, especially as the system mass increases. The companion
mass-ratio distribution is a unique probe into the conditions of the collapsing
cloud core and circumstellar disk(s) of the binary fragments. Inside $a \sim
1000$ AU the disks from the two forming stars can interact, and additionally
companions can form directly through disk fragmentation. We should therefore
expect the mass-ratio distribution of close companions ($a 100$ AU) to
differ from that of wide companions. This prediction is difficult to test using
traditional methods, especially with intermediate-mass primary stars, for a
variety of observational reasons. We present the results of a survey searching
for companions to A- and B-type stars using the direct spectral detection
method, which is sensitive to late-type companions within $1"$ of the
primary and which has no inner working angle. We estimate the temperatures and
surface gravity of most of the 341 sample stars, and derive their masses and
ages. We additionally estimate the temperatures and masses of the 64 companions
we find, 23 of which are new detections. We find that the mass-ratio
distribution for our sample has a maximum near $q 0.3$. Our mass-ratio
distribution has a very different form than in previous work, where it is
usually well-described by a power law, and indicates that close companions to
intermediate-mass stars experience significantly different accretion histories
or formation mechanisms than wide companions.
Description
The Close Companion Mass-Ratio Distribution of Intermediate-Mass Stars
cite arxiv:1604.06456Comment: Accepted to the Astronomical Journal. 26 pages, 7 figures, 5 tables. The code to replicate the analysis is available at https://github.com/kgullikson88/BinaryInference All of the spectra used in this work, as well as a significant portion of the intermediate data products and MCMC samples are available at: https://zenodo.org/record/48073 and https://zenodo.org/record/46482
%0 Generic
%1 gullikson2016close
%A Gullikson, Kevin
%A Kraus, Adam
%A Dodson-Robinson, Sarah
%D 2016
%K multiplicity
%T The Close Companion Mass-Ratio Distribution of Intermediate-Mass Stars
%U http://arxiv.org/abs/1604.06456
%X Binary stars and higher-order multiple systems are an ubiquitous outcome of
star formation, especially as the system mass increases. The companion
mass-ratio distribution is a unique probe into the conditions of the collapsing
cloud core and circumstellar disk(s) of the binary fragments. Inside $a \sim
1000$ AU the disks from the two forming stars can interact, and additionally
companions can form directly through disk fragmentation. We should therefore
expect the mass-ratio distribution of close companions ($a 100$ AU) to
differ from that of wide companions. This prediction is difficult to test using
traditional methods, especially with intermediate-mass primary stars, for a
variety of observational reasons. We present the results of a survey searching
for companions to A- and B-type stars using the direct spectral detection
method, which is sensitive to late-type companions within $1"$ of the
primary and which has no inner working angle. We estimate the temperatures and
surface gravity of most of the 341 sample stars, and derive their masses and
ages. We additionally estimate the temperatures and masses of the 64 companions
we find, 23 of which are new detections. We find that the mass-ratio
distribution for our sample has a maximum near $q 0.3$. Our mass-ratio
distribution has a very different form than in previous work, where it is
usually well-described by a power law, and indicates that close companions to
intermediate-mass stars experience significantly different accretion histories
or formation mechanisms than wide companions.
@misc{gullikson2016close,
abstract = {Binary stars and higher-order multiple systems are an ubiquitous outcome of
star formation, especially as the system mass increases. The companion
mass-ratio distribution is a unique probe into the conditions of the collapsing
cloud core and circumstellar disk(s) of the binary fragments. Inside $a \sim
1000$ AU the disks from the two forming stars can interact, and additionally
companions can form directly through disk fragmentation. We should therefore
expect the mass-ratio distribution of close companions ($a \lesssim 100$ AU) to
differ from that of wide companions. This prediction is difficult to test using
traditional methods, especially with intermediate-mass primary stars, for a
variety of observational reasons. We present the results of a survey searching
for companions to A- and B-type stars using the direct spectral detection
method, which is sensitive to late-type companions within $\sim 1"$ of the
primary and which has no inner working angle. We estimate the temperatures and
surface gravity of most of the 341 sample stars, and derive their masses and
ages. We additionally estimate the temperatures and masses of the 64 companions
we find, 23 of which are new detections. We find that the mass-ratio
distribution for our sample has a maximum near $q \sim 0.3$. Our mass-ratio
distribution has a very different form than in previous work, where it is
usually well-described by a power law, and indicates that close companions to
intermediate-mass stars experience significantly different accretion histories
or formation mechanisms than wide companions.},
added-at = {2016-04-25T20:35:28.000+0200},
author = {Gullikson, Kevin and Kraus, Adam and Dodson-Robinson, Sarah},
biburl = {https://www.bibsonomy.org/bibtex/22486482c5070cc61ce689c02ef0d13c8/superjenwinters},
description = {The Close Companion Mass-Ratio Distribution of Intermediate-Mass Stars},
interhash = {e52939670b5569b4a0c384fef75f9d7d},
intrahash = {2486482c5070cc61ce689c02ef0d13c8},
keywords = {multiplicity},
note = {cite arxiv:1604.06456Comment: Accepted to the Astronomical Journal. 26 pages, 7 figures, 5 tables. The code to replicate the analysis is available at https://github.com/kgullikson88/BinaryInference All of the spectra used in this work, as well as a significant portion of the intermediate data products and MCMC samples are available at: https://zenodo.org/record/48073 and https://zenodo.org/record/46482},
timestamp = {2016-04-25T20:35:28.000+0200},
title = {The Close Companion Mass-Ratio Distribution of Intermediate-Mass Stars},
url = {http://arxiv.org/abs/1604.06456},
year = 2016
}