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The GALAH survey : Unresolved triple Sun-like stars discovered by the Gaia mission

Čotar, Klemen; Zwitter, Tomaž; Traven, Gregor LU ; Kos, Janez; Asplund, Martin; Bland-Hawthorn, Joss; Buder, Sven; D'Orazi, Valentina; De Silva, Gayandhi M. and Lin, Jane, et al. (2019) In Monthly Notices of the Royal Astronomical Society 487(2). p.2474-2490
Abstract

The latest Gaia data release enables us to accurately identify stars that are more luminous than would be expected on the basis of their spectral type and distance. During an investigation of the 329 best solar twin candidates uncovered among the spectra acquired by the GALAH survey, we identified 64 such overluminous stars. In order to investigate their exact composition, we developed a data-driven methodology that can generate a synthetic photometric signature and spectrum of a single star. By combining multiple such synthetic stars into an unresolved binary or triple system and comparing the results to the actual photometric and spectroscopic observations, we uncovered 6 definitive triple stellar system candidates and an additional... (More)

The latest Gaia data release enables us to accurately identify stars that are more luminous than would be expected on the basis of their spectral type and distance. During an investigation of the 329 best solar twin candidates uncovered among the spectra acquired by the GALAH survey, we identified 64 such overluminous stars. In order to investigate their exact composition, we developed a data-driven methodology that can generate a synthetic photometric signature and spectrum of a single star. By combining multiple such synthetic stars into an unresolved binary or triple system and comparing the results to the actual photometric and spectroscopic observations, we uncovered 6 definitive triple stellar system candidates and an additional 14 potential candidates whose combined spectrum mimics the solar spectrum. Considering the volume correction factor for a magnitude-limited survey, the fraction of probable unresolved triple stars with long orbital periods is ~2 per cent. Possible orbital configurations of the candidates were investigated using the selection and observational limits. To validate the discovered multiplicity fraction, the same procedure was used to evaluate the multiplicity fraction of other stellar types.

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subject
keywords
Binaries: general, Galaxy: stellar content, Methods: data analysis, Stars: solar-type
in
Monthly Notices of the Royal Astronomical Society
volume
487
issue
2
pages
17 pages
publisher
Oxford University Press (OUP)
external identifiers
  • scopus:85071159376
ISSN
0035-8711
DOI
10.1093/mnras/stz1397
language
English
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yes
id
517c0509-541e-4a96-ba11-ad5757b02f81
date added to LUP
2019-09-12 13:28:43
date last changed
2019-09-30 07:46:34
@article{517c0509-541e-4a96-ba11-ad5757b02f81,
  abstract     = {<p>The latest Gaia data release enables us to accurately identify stars that are more luminous than would be expected on the basis of their spectral type and distance. During an investigation of the 329 best solar twin candidates uncovered among the spectra acquired by the GALAH survey, we identified 64 such overluminous stars. In order to investigate their exact composition, we developed a data-driven methodology that can generate a synthetic photometric signature and spectrum of a single star. By combining multiple such synthetic stars into an unresolved binary or triple system and comparing the results to the actual photometric and spectroscopic observations, we uncovered 6 definitive triple stellar system candidates and an additional 14 potential candidates whose combined spectrum mimics the solar spectrum. Considering the volume correction factor for a magnitude-limited survey, the fraction of probable unresolved triple stars with long orbital periods is ~2 per cent. Possible orbital configurations of the candidates were investigated using the selection and observational limits. To validate the discovered multiplicity fraction, the same procedure was used to evaluate the multiplicity fraction of other stellar types.</p>},
  author       = {Čotar, Klemen and Zwitter, Tomaž and Traven, Gregor and Kos, Janez and Asplund, Martin and Bland-Hawthorn, Joss and Buder, Sven and D'Orazi, Valentina and De Silva, Gayandhi M. and Lin, Jane and Martell, Sarah L. and Sharma, Sanjib and Simpson, Jeffrey D. and Zucker, Daniel B. and Horner, Jonathan and Lewis, Geraint F. and Nordlander, Thomas and Ting, Yuan Sen and Wittenmyer, Rob A.},
  issn         = {0035-8711},
  keyword      = {Binaries: general,Galaxy: stellar content,Methods: data analysis,Stars: solar-type},
  language     = {eng},
  number       = {2},
  pages        = {2474--2490},
  publisher    = {Oxford University Press (OUP)},
  series       = {Monthly Notices of the Royal Astronomical Society},
  title        = {The GALAH survey : Unresolved triple Sun-like stars discovered by the Gaia mission},
  url          = {http://dx.doi.org/10.1093/mnras/stz1397},
  volume       = {487},
  year         = {2019},
}