Triple System stein 2051 (G 175-34).

Strand, K. Aa.

doi:10.1086/112119

Cited by 21 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…-WD0426+588 is in a wide binary (Stein2051) with an Mstar companion. There is some suggestion that this is a triple system (Strand 1977). In their model, the red component is an astrometric binary.…”

Section: Questionable Multiplicitymentioning

confidence: 99%

The binarity of the local white dwarf population

Toonen

Hollands

Gänsicke

et al. 2017

A&A

182

194

View full text Add to dashboard Cite

Context. As endpoints of stellar evolution, white dwarfs (WDs) are powerful tools to study the evolutionary history of the Galaxy. In particular, the multiplicity of WDs contains information regarding the formation and evolution of binary systems. Aims. Can we understand the multiplicity of the local WD sample from a theoretical point of view? Population synthesis methods are often applied to estimate stellar space densities and event rates, but how well are these estimates calibrated? This can be tested by a comparison with the 20 pc sample, which contains ≃ 100 stars and is minimally affected by selection biases. Methods. We model the formation and evolution of single stars and binaries within 20 pc with a population synthesis approach. We construct a model of the current sample of WDs and differentiate between WDs in different configurations, that is single WDs, and resolved and unresolved binaries containing a WD with either a main-sequence (MS) component or with a second WD. We also study the effect of different assumptions concerning the star formation history, binary evolution, and the initial distributions of binary parameters. We compile from the literature the available information on the sample of WDs within 20 pc, with a particular emphasis on their multiplicity, and compare this to the synthetic models. Results. The observed space densities of single and binary WDs are well reproduced by the models. The space densities of the most common WD systems (single WDs and unresolved WD-MS binaries) are consistent within a factor two with the observed value. We find a discrepancy only for the space density of resolved double WDs. We exclude that observational selection effects, fast stellar winds, or dynamical interactions with other objects in the Milky Way explain this discrepancy. We find that either the initial mass ratio distribution in the Solar neighbourhood is biased towards low mass-ratios, or more than ten resolved DWDs have been missed observationally in the 20 pc sample. Furthermore, we show that the low binary fraction of WD systems (∼25%) compared to Solartype MS-MS binaries (∼50%) is consistent with theory, and is mainly caused by mergers in binary systems, and to a lesser degree by WDs hiding in the glare of their companion stars. Lastly, Gaia will dramatically increase the size of the volume-limited WD sample, detecting the coolest and oldest WDs out to ≃ 50 pc. We provide a detailed estimate of the number of single and binary WDs in the Gaia sample.

show abstract

Section: Questionable Multiplicitymentioning

confidence: 99%

The binarity of the local white dwarf population

Toonen

Hollands

Gänsicke

et al. 2017

A&A

182

194

View full text Add to dashboard Cite

show abstract

“…The actual mass of Stein 2051 B has been a matter of debate. Photographic observations extending back to 1908 have been used to claim departures from linear PMs of A and B (25,26), implying a detection of orbital motion and a mass ratio of M B /M A = 2.07. Assuming A to be a normal M4 main-sequence star of 0.24 M⊙, the mass of B was estimated (25,26) to be 0.50 M⊙.…”

Section: The Stein 2051 Binary Systemmentioning

confidence: 99%

Relativistic deflection of background starlight measures the mass of a nearby white dwarf star

Sahu

Anderson

Casertano

et al. 2017

Science

138

100

View full text Add to dashboard Cite

Gravitational deflection of starlight around the Sun during the 1919 total solar eclipse provided measurements that confirmed Einstein's general theory of relativity. We have used the Hubble Space Telescope to measure the analogous process of astrometric microlensing caused by a nearby star, the white dwarf Stein 2051 B. As Stein 2051 B passed closely in front of a background star, the background star's position was deflected. Measurement of this deflection at multiple epochs allowed us to determine the mass of Stein 2051 B-the sixth-nearest white dwarf to the Sun-as 0.675 ± 0.051 solar masses. This mass determination provides confirmation of the physics of degenerate matter and lends support to white dwarf evolutionary theory.

show abstract

“…( f ) Primary is SB2 (Llamas 2014). (g) Primary is an astrometric binary separated by 0.07 arcseconds (Strand 1977). (h) The primary is a SB2 (Schöfer 2015).…”

Section: Appendix A: Long Tablesmentioning

confidence: 99%

CARMENES input catalogue of M dwarfs II. High-resolution imaging with FastCam

Cortes-Contreras,

Bejar,

Caballero

et al. 2016

Preprint

View full text Add to dashboard Cite

Aims. We search for low-mass companions of M dwarfs and characterize their multiplicity fraction with the purpose of helping in the selection of the most appropriate targets for the CARMENES exoplanet survey. Methods. We obtained high-resolution images in the I band with the lucky imaging instrument FastCam at the 1.5 m Telescopio Carlos Sánchez for 490 mid-to late-M dwarfs. For all the detected binaries, we measured angular separations, position angles, and magnitude differences in the I band. We also calculated the masses of each individual component and estimated orbital periods, using the available magnitude and colour relations for M dwarfs and our own M J -spectral type and mass-M I relations. To avoid biases in our sample selection, we built a volume-limited sample of M0.0-M5.0 dwarfs that is complete up to 86 % within 14 pc. Results. From the 490 observed stars, we detected 80 companions in 76 systems, of which 30 are new discoveries. Another six companion candidates require additional astrometry to confirm physical binding. The multiplicity fraction in our observed sample is 16.7 ± 2.0 %. The bias-corrected multiplicity fraction in our volume-limited sample is 19.5 ± 2.3 % for angular separations of 0.2 to 5.0 arcsec (1.4-65.6 au), with a peak in the distribution of the projected physical separations at 2.5-7.5 au. For M0.0-M3.5 V primaries, our search is sensitive to mass ratios higher than 0.3 and there is a higher density of pairs with mass ratios over 0.8 compared to those at lower mass ratios. Binaries with projected physical separations shorter than 50 au also tend to be of equal mass. For 26 of our systems, we estimated orbital periods shorter than 50 a, 10 of which are presented here for the first time. We measured variations in angular separation and position angle that are due to orbital motions in 17 of these systems. The contribution of binaries and multiples with angular separations shorter than 0.2 arcsec, longer than 5.0 arcsec, and of spectroscopic binaries identified from previous searches, although not complete, may increase the multiplicity fraction of M dwarfs in our volume-limited sample to at least 36%.

show abstract

Triple System stein 2051 (G 175-34).

Cited by 21 publications

References 0 publications

The binarity of the local white dwarf population

The binarity of the local white dwarf population

Relativistic deflection of background starlight measures the mass of a nearby white dwarf star

CARMENES input catalogue of M dwarfs II. High-resolution imaging with FastCam

Contact Info

Product

Resources

About