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Discovery and characterization of 3000+ main-sequence binaries from APOGEE spectra

El-Badry, Kareem and Ting, Yuan-Sen and Rix, Hans-Walter and Quataert, Eliot and Weisz, Daniel R. and Cargile, Phillip and Conroy, Charlie and Hogg, David W. and Bergemann, Maria and Liu, Chao (2018) Discovery and characterization of 3000+ main-sequence binaries from APOGEE spectra. Monthly Notices of the Royal Astronomical Society, 476 (1). pp. 528-553. ISSN 0035-8711. doi:10.1093/mnras/sty240.

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We develop a data-driven spectral model for identifying and characterizing spatially unresolved multiple-star systems and apply it to APOGEE DR13 spectra of main-sequence stars. Binaries and triples are identified as targets whose spectra can be significantly better fit by a superposition of two or three model spectra, drawn from the same isochrone, than any single-star model. From an initial sample of ∼20 000 main-sequence targets, we identify ∼2500 binaries in which both the primary and secondary stars contribute detectably to the spectrum, simultaneously fitting for the velocities and stellar parameters of both components. We additionally identify and fit ∼200 triple systems, as well as ∼700 velocity-variable systems in which the secondary does not contribute detectably to the spectrum. Our model simplifies the process of simultaneously fitting single- or multi-epoch spectra with composite models and does not depend on a velocity offset between the two components of a binary, making it sensitive to traditionally undetectable systems with periods of hundreds or thousands of years. In agreement with conventional expectations, almost all the spectrally identified binaries with measured parallaxes fall above the main sequence in the colour–magnitude diagram. We find excellent agreement between spectrally and dynamically inferred mass ratios for the ∼600 binaries in which a dynamical mass ratio can be measured from multi-epoch radial velocities. We obtain full orbital solutions for 64 systems, including 14 close binaries within hierarchical triples. We make available catalogues of stellar parameters, abundances, mass ratios, and orbital parameters.

Item Type:Article
Related URLs:
URLURL TypeDescription
El-Badry, Kareem0000-0002-6871-1752
Ting, Yuan-Sen0000-0001-5082-9536
Rix, Hans-Walter0000-0003-4996-9069
Quataert, Eliot0000-0001-9185-5044
Weisz, Daniel R.0000-0002-6442-6030
Cargile, Phillip0000-0002-1617-8917
Conroy, Charlie0000-0002-1590-8551
Hogg, David W.0000-0003-2866-9403
Bergemann, Maria0000-0002-9908-5571
Liu, Chao0000-0001-7049-493X
Additional Information:© 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. We are grateful to the anonymous referee for a constructive report. We thank Gaspard Duchêne, Keith Hawkins, Jessica Lu, Hans-Günter Ludwig, Adrian Price-Whelan, and Silvia Toonen for helpful conversations. We are grateful to Jan Rybizki for assistance in creating mock catalogues with galaxia, and to Anna Ho for help with the Cannon. This project was developed in part at the 2017 Heidelberg Gaia Sprint, hosted by the Max-Planck-Institut für Astronomie, Heidelberg. KE acknowledges support from the SFB 881 program (A3), a Berkeley Fellowship, a Hellman award for graduate study, and an NSF graduate research fellowship. HWR received support from the European Research Council under the European Union’s Seventh Framework Programme (FP 7) ERC Grant Agreement no. [321035]. YST is supported by the Australian Research Council Discovery Program DP160103747, the Carnegie-Princeton Fellowship and the Martin A. and Helen Chooljian Membership from the Institute for Advanced Study at Princeton. EQ is supported in part by a Simons Investigator Award from the Simons Foundation. DRW is supported by a fellowship from the Alfred P. Sloan Foundation. CC acknowledges support from NASA grant NNX15AK14G, NSF grant AST-1313280, and the Packard Foundation. The analysis in this paper relied on the python packages numpy (Van Der Walt, Colbert & Varoquaux 2011), matplotlib (Hunter 2007), and astropy (Astropy Collaboration et al. 2013).
Funding AgencyGrant Number
Deutsche Forschungsgemeinschaft (DFG)SFB 881
University of California, BerkeleyUNSPECIFIED
Hellman FellowshipUNSPECIFIED
NSF Graduate Research FellowshipUNSPECIFIED
European Research Council (ERC)321035
Australian Research CouncilDP160103747
Carnegie-Princeton FellowshipUNSPECIFIED
Institute for Advanced StudyUNSPECIFIED
Simons FoundationUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
David and Lucile Packard FoundationUNSPECIFIED
Issue or Number:1
Record Number:CaltechAUTHORS:20230105-893221000.4
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:118688
Deposited By: George Porter
Deposited On:20 Jan 2023 20:15
Last Modified:20 Jan 2023 20:15

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