A UBV Study of 94 Wide Visual Binaries.

Tolbert, C. R.

doi:10.1086/147852

Cited by 29 publications

(15 citation statements)

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“…There is a sharp cutoff in the number of very wide binaries with physical separations greater than 0.1 pc, possibly dictated by dynamical evolution, as stated in classical (Tolbert 1964;Kraicheva et al 1985;Abt 1988;Weinberg & Wasserman 1988;Weis 1988;Close et al 1990;Latham et al 1991;Wasserman & Weinberg 1991 and references above) and modern works (Allen et al 2000;Palasi 2000;Chanamé & Gould 2004;Lépine & Bongiorno 2007;Makarov et al 2008). My aim is to characterise and look for very wide binaries and multiple systems with projected physical separations larger than s = 0.1 pc (2 × 10 4 AU).…”

Section: Introductionmentioning

confidence: 88%

Reaching the boundary between stellar kinematic groups and very wide binaries

Caballero¹

2009

A&A

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Aims. I look for and characterise very wide binaries and multiple systems with projected physical separations larger than s = 0.1 pc, which is generally believed to be a sharp upper limit to the distribution of wide binary semimajor axes. Methods. I investigated in detail 30 Washington double stars with angular separations of ρ > 1000 arcsec. I discarded 23 of them as probably unbound systems based on discordant astrometry, photometry, spectral types, and radial velocities. The remaining seven systems were subject to a comprehensive data compilation and derivation (multi-wavelength photometry, heliocentric distance, multiplicity, age, mass, metallicity, membership in a young kinematic group). Results. Of the seven very wide systems, six have projected physical separations greater than the hypothetical cutoff at s = 0.1 pc and four have separations s > 0.2 pc. Although there are two systems in young kinematic groups (namely HD 136654 and BD+32 2572 in the Hyades Supercluster, and AU Mic and AT Mic AB in the β Pictoris moving group), there is no clear prevalence of young systems (τ < 1 Ga) among these very wide binaries. Finally, I compare the binding energies of the seven systems with those of other weakly bound systems in the field.

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Section: Introductionmentioning

confidence: 88%

Reaching the boundary between stellar kinematic groups and very wide binaries

Caballero¹

2009

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“…Tolbert (1964) classify the star as a variable in a binary system. They identify the components as B8-7 III and B6-7 IV, suggesting a period of P = 230 yr.…”

Section: Appendix A: Notes On Individual Be Starsmentioning

confidence: 99%

Stellar parameters of Be stars observed with X-shooter

Shokry

Rivinius

Mehner

et al. 2018

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Aims. The X-shooter archive of several thousand telluric standard star spectra was skimmed for Be and Be shell stars to derive the stellar fundamental parameters and statistical properties, in particular for the less investigated late-type Be stars and the extension of the Be phenomenon into early A stars.Methods. An adapted version of the BCD method is used, using the Balmer discontinuity parameters to determine effective temperature and surface gravity. This method is optimally suited for late B stars. The projected rotational velocity was obtained by profile fitting to the Mg ii lines of the targets, and the spectra were inspected visually for the presence of peculiar features such as the infrared Ca ii triplet or the presence of a double Balmer discontinuity. The Balmer line equivalent widths were measured, but they are only useful for determining the pure emission contribution in a subsample of Be stars owing to uncertainties in determining the photospheric contribution. Results. A total of 78, mostly late-type, Be stars, were identified in the X-shooter telluric standard star archive, out of which 48 had not been reported before. We confirm the general trend that late-type Be stars have more tenuous disks and are less variable than earlytype Be stars. The relatively large number (48) of relatively bright (V > 8.5) additional Be stars casts some doubt on the statistics of late-type Be stars; they are more common than currently thought. The Be/B star fraction may not strongly depend on spectral subtype.

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“…However, the maximum projected physical separation of a wide binary is still a matter of discussion: Some authors consider a cutoff in the number of wide binaries at 2 × 10 4 au (∼0.1 pc), which is the typical size of protostellar cores (Tolbert 1964;Abt 1988;Wasserman & Weinberg 1991;Allen et al 2000;Tokovinin & Lépine 2012), while others contemplate separations of 2 × 10 5 au (∼1 pc) or more (Jiang & Tremaine 2009;Caballero 2009;Shaya & Olling 2011). Such wide common proper-motion pair candidates, which give their name to the title of this series of papers, can be either unbound members of the same young stellar kinematic group that by chance are co-moving (Tokovinin 2014a) or bound "binaries" of very low binding energies at the limit of disruption (Caballero 2010).…”

Section: Introductionmentioning

confidence: 99%

Reaching the boundary between stellar kinematic groups and very wide binaries

Alonso-Floriano

Caballero

Cortés-Contreras

et al. 2015

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Aims. We look for common proper motion companions to stars of the nearby young β Pictoris moving group. Methods. First, we compiled a list of 185 β Pictoris members and candidate members from 35 representative works. Next, we used the Aladin and STILTS virtual observatory tools and the PPMXL proper motion and Washington Double Star catalogues to look for companion candidates. The resulting potential companions were subjects of a dedicated astro-photometric follow-up using public data from all-sky surveys. After discarding 67 sources by proper motion and 31 by colour-magnitude diagrams, we obtained a final list of 36 common proper motion systems. The binding energy of two of them is perhaps too small to be considered physically bound. Results. Of the 36 pairs and multiple systems, eight are new, 16 have only one stellar component previously classified as a β Pictoris member, and three have secondaries at or below the hydrogen-burning limit. Sixteen stars are reported here for the first time as moving group members. The unexpected large number of high-order multiple systems, 12 triples and two quadruples among 36 systems, may suggest a biased list of members towards close binaries or an increment of the high-order-multiple fraction for very wide systems.

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A UBV Study of 94 Wide Visual Binaries.

Cited by 29 publications

References 0 publications

Reaching the boundary between stellar kinematic groups and very wide binaries

Reaching the boundary between stellar kinematic groups and very wide binaries

Stellar parameters of Be stars observed with X-shooter

Reaching the boundary between stellar kinematic groups and very wide binaries

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