Duplicity Statistics and Binary Formation

Robert Mathieu (Univeristy of Wisconsin)

Abstract:

The typical product of the star-formation process is a binary star. I will review the population of main-sequence binary stars, including frequency as a function of primary mass and the distributions of orbital elements among solar-mass binary stars. I will then review the pre-main-sequence binary population, with particular emphasis on binary frequencies and orbital eccentricities. Accretion disks are central to our present picture of star formation, and I will review the impact of binary stars upon accretion disk structure. Finally, I will mention a few key roles of high-angular-resolution techniques for the binary formation question, including the calibration of pre-main-sequence evolutionary tracks and the structure of protoplanetary disks.

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Primary References:

• Multiplicity among solar-type stars in the solar neighborhood. II - Distribution of the orbital elements in an unbiased sample
  Duquennoy, A.; Mayor, M., A&A, 248, 485 (1991)

• Young binary stars and associated disks
  Mathieu, R. D.; Ghez, A. M.; Jensen, E. L. N.; Simon, M.,
  Protostars and Planets IV (Mannings, V., Boss, A.P, Russell, S.S., eds.), 703 (2000).

Secondary Readings:

• GG Tauri: The ring world
  Guilloteau, S.; Dutrey, A.; Simon, M., A&A, 348, 570 (1999).

• Interactions of young binaries with disks
  Lubow, S. H.; Artymowicz, P.,
  Protostars and Planets IV (Mannings, V., Boss, A.P, Russell, S.S., eds.), 731 (2000).

• ICCD speckle observations of binary stars. XIX - an astrometric/spectroscopic survey of O stars
  Mason, B. D.; Gies, D. R.; Hartkopf, W. I.; Bagnuolo, W. G., Jr.; Brummelaar, T. T.; McAlister, H. A.,
  Astron. J. 11, 821 (1998).

• Pre-main-sequence binary stars
  R.D. Mathieu
  Ann. Rev. Astron. Astrophys. 32, 465 (1994).

• On the mass-ratio distribution of spectroscopic binaries with solar-type primaries
  Mazeh, T.; Goldberg, D.; Duquennoy, A.; Mayor, M.,
  Astrophys. J. 401, 265 (1992).