Spectroscopic binaries among Hipparcos M giants ⋆ II . Binary frequency

نویسنده

  • A. Jorissen
چکیده

Context. This paper is the second one in a series devoted to the study of properties of binaries involving M giants. Aims. The binary frequency of field M giants is derived and compared with the binary fraction of K giants. Methods. Diagrams of the CORAVEL spectroscopic parameter Sb (measuring the average line-width) vs. radial-velocity standard deviation for our samples are used to define appropriate binarity criteria. These then serve to extract the binarity fraction among the M giants. Comparison is made to earlier data on K giants binarity frequency. The Sb parameter is discussed in relation to global stellar parameters and the Sb vs. stellar radius relation is used to identify fast rotators. Results. We find that the spectroscopic binary detection rate among field M giants, in a sample with a low number of velocity measurements (∼ 2), unbiased toward earlier known binaries, is 6.3%. This is less than half of the analogous rate for field K giants, likely resulting from a real difference. This difference originates in the greater difficulty of finding binaries among M giants because of their smaller orbital velocity amplitudes and larger intrinsic jitter and in the different distributions of K and M giants in the eccentricity – period diagram. A larger detection rate was obtained in a smaller M giant sample with more radial velocity measurements per object: 11.1% confirmed plus 2.7% possible binaries. The CORAVEL spectroscopic parameter Sb was found to correlate better with the stellar radius than with either luminosity or effective temperature separately. Two outliers of the Sb vs. stellar radius relation, HD 190658 and HD 219654, have been recognized as fast rotators. The rotation is companion-induced, as both objects turn out to be spectroscopic binaries.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Spectroscopic binaries among Hipparcos M giants ⋆ , ⋆ ⋆ I . Data , orbits , and intrinsic variations

Context. This paper is a follow-up on the vast effort to collect radial velocity data for stars belonging to the Hipparcos survey. Aims. We aim at extending the orbital data available for binaries with M giant primaries. The data presented in this paper will be used in the companion papers of this series to (i) derive the binary frequency among M giants and compare it to that of K giants (Paper...

متن کامل

Spectroscopic binaries among Hipparcos M giants ⋆ III . The eccentricity - period diagram and mass - transfer signatures

Context. This paper is the third one in a series devoted to studying the properties of binaries involving M giants. Aims. We use a new set of orbits to construct the first (e− logP ) diagram of an extensive sample of M giant binaries, to obtain their mass-function distribution, and to derive evolutionary constraints for this class of binaries and related systems. Methods. The orbital properties...

متن کامل

Re - processing the Hipparcos Transit Data and Intermediate

Only 235 entries were processed as astrometric binaries with orbits in the Hipparcos and Tycho Catalogue (ESA 1997). However, the Intermediate Astrometric Data (IAD) and Transit Data (TD) made available by ESA make it possible to re-process the stars that turned out to be spectroscopic binaries after the completion of the Catalogue. This paper illustrates how TD and IAD may be used in conjuncti...

متن کامل

Reprocessing the Hipparcos Intermediate Astrometric Data of spectroscopic binaries : II . Systems with a giant component ⋆

By reanalyzing the Hipparcos Intermediate Astrometric Data of a large sample of spectroscopic binaries containing a giant, we obtain a sample of 29 systems fulfilling a carefully derived set of constraints and hence for which we can derive an accurate orbital solution. Of these, one is a double-lined spectroscopic binary and six were not listed in the DMSA/O section of the catalogue. Using our ...

متن کامل

Hipparcos Astrometric Orbit and Evolutionary Status of Hr 6046

The previously known, 6-yr spectroscopic binary HR 6046 has been speculated in the past to contain a compact object as the secondary. A recent study has re-determined the orbit with great accuracy, and shown that the companion is an evolved but otherwise normal star of nearly identical mass as the primary, which is also a giant. The binary motion was detected by the Hipparcos mission but was no...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2009