Proper-motion binaries in the Hipparcos catalogue

Abstract

Context. This paper is the last in a series devoted to the analysis of the binary content of the Hipparcos Catalogue. Aims. The comparison of the proper motions constructed from positions spanning a short (Hipparcos) or long time (Tycho-2) makes it possible to uncover binaries with periods of the order of or somewhat larger than the short time span (in this case, the 3 yr duration of the Hipparcos mission), since the unrecognised orbital motion will then add to the proper motion. Methods. A list of candidate proper motion binaries is constructed from a carefully designed χ 2 test evaluating the statistical significance of the difference between the Tycho-2 and Hipparcos proper motions for 103 134 stars in common between the two catalogues (excluding components of visual systems). Since similar lists of proper-motion binaries have already been constructed, the present paper focuses on the evaluation of the detection efficiency of proper-motion binaries, using different kinds of control data (mostly radial velocities). The detection rate for entries from the Ninth Catalogue of Spectroscopic Binary Orbits (S B 9 ) is evaluated, as well as for stars like barium stars, which are known to be all binaries, and finally for spectroscopic binaries identified from radial velocity data in the Geneva-Copenhagen survey of F and G dwarfs in the solar neighbourhood. Results. Proper motion binaries are efficiently detected for systems with parallaxes in excess of ∼20 mas, and periods in the range 1000-30 000 d. The shortest periods in this range (1000-2000 d, i.e., once to twice the duration of the Hipparcos mission) may appear only as DMSA/G binaries (accelerated proper motion in the Hipparcos Double and Multiple System Annex). Proper motion binaries detected among S B 9 systems having periods shorter than about 400 d hint at triple systems, the proper-motion binary involving a component with a longer orbital period. A list of 19 candidate triple systems is provided. Binaries suspected of having low-mass (brown-dwarf-like) companions are listed as well. Among the 37 barium stars with parallaxes larger than 5 mas, only 7 exhibit no evidence for duplicity whatsoever (be it spectroscopic or astrometric). Finally, the fraction of proper-motion binaries shows no significant variation among the various (regular) spectral classes, when due account is taken for the detection biases.

To Ba or not to Ba: Enrichment ins-process elements in binary systems with WD companions of various masses

“…It is only quite recently that a clear direct argument was presented by Gray et al (2011) in the form of UV excess flux from these systems detected by GALEX that is attributable to a warm WD. Earlier studies by Schindler et al (1982), Dominy & Lambert (1983), Böhm-Vitense et al (1984, Jorissen et al (1996), and Frankowski & Jorissen (2006) found similar evidence, although somewhat less convincingly or for a smaller set.…”

“…References. (1) Fekel et al (1993); (2) Landsman et al (1993); (3) Vennes et al (1998) (4) Burleigh et al (1997); (5) Merle et al (2014); (6) Jorissen et al (1996); (7) ; (8) Stefanik et al (2011); (9) Dominy & Lambert (1983); (10) Griffin & Keenan (1992); (11) Schindler et al (1982); (12) Griffin (2006); (13) Frankowski & Jorissen (2006); (14) Böhm-Vitense (1980); (15) Jorissen et al (1998); (16) Jorissen et al (1995); (17) Fekel & Simon (1985).…”

870 μm observations of evolved stars with LABOCA

“…One possible explanation given by Chiu et al (2006) is a much closer companion that has escaped detection. This possibility is deemed viable by Makarov & Kaplan (2005) and Frankowski et al (2007) who found significant discrepancies between Hipparcos and Tycho-2 proper motions of the star, which indicates additional orbital motion with an orbital period shorter than the 6000 years derived by Knapp et al (1999). Sacuto et al (2008) attempted to resolve the disc with MIDI/VLTI interferometric data at 10 μm, but the data were not conclusive.…”

Are planetary nebulae derived from multiple evolutionary scenarios?

“…Mz 3), with or without symbiotic characteristics. Lastly, the yellow symbiotic stars (Frankowski & Jorissen 2007) may be tentatively included here, plus the EGB 6-like CSPNe, associated with dense, ionized circumstellar nebulae Miszalski et al 2010). …”