Observations of the binary star 61 Cyg on the 26 inch refractor at the Pulkovo observatory

Gorshanov, D. L.; Shakht, N. A.; Kisselev, A. A.

doi:10.1007/s10511-006-0038-7

Cited by 17 publications

(16 citation statements)

References 9 publications

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“…The spectral types of its two members (K5V and K7V) ideally complement our previous studies of α Cen A & B (G2V+K1V, Kervella et al 2003a;Bigot et al 2006). The masses of 61 Cyg A & B are controversial, with estimates ranging from approximately 0.74 and 0.46 M (Gorshanov et al 2006) to 0.67 and 0.59 M (Walker et al 1995). With effective temperatures of about 4 400 and 4 000 K, they shine with luminosities of only 0.15 and 0.08 L .…”

Section: Introductionsupporting

confidence: 71%

“…The variation of the α parameter of the convection depth did not help either. From this we conclude that the masses proposed by Gorshanov et al (2006) are not reproducible by our modeling within ±0.05 M . For this reason, we decided to use as a starting value the older mass determination by Walker et al (1995) of 0.67 and 0.59 M .…”

Section: Modeling With Cesam2kmentioning

confidence: 50%

“…Interestingly, an 8 M J companion was proposed by Strand (1943Strand ( , 1957, based on astrometric measurements. This possibility was suggested again by Deich & Orlova (1977), Deich (1978), and recently by Gorshanov et al (2006), based on astrometry of the two stars. One should note however that a giant planet with a mass around 10 M J and the age of 61 Cyg will be extremely faint, according for instance to the models by Baraffe et al (2003), with an absolute K band magnitude of M K ≈ 30, and an apparent magnitude of m K ≈ 28.…”

Section: Angular Diameter Discussionmentioning

confidence: 69%

“…We then tried to fit the evolutionary models within the error boxes of both stars with the masses proposed by Gorshanov et al (2006) of 0.74 and 0.46 M . In this process, we explored a range of abundance Z/X by changing the observed value by ±0.15 dex and Y by ±0.01 dex.…”

Section: Modeling With Cesam2kmentioning

confidence: 99%

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The radii of the nearby K5V and K7V stars 61 Cygni A & B

Kervella¹,

Mérand

Pichon

et al. 2008

A&A

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Context. The main sequence binary star 61 Cyg (K5V+K7V) is our nearest stellar neighbour in the northern hemisphere. This proximity makes it a particularly well suited system for very high accuracy interferometric radius measurements. Aims. Our goal is to constrain the poorly known evolutionary status and age of this bright binary star. Methods. We obtained high accuracy interferometric observations in the infrared K band, using the CHARA/FLUOR instrument. We then computed evolutionary models of 61 Cyg A & B with the CESAM2k code. As model constraints, we used a combination of observational parameters from classical observation methods (photometry, spectroscopy) as well as our new interferometric radii. Results. The measured limb darkened disk angular diameters are θ LD (A) = 1.775 ± 0.013 mas and θ LD (B) = 1.581 ± 0.022 mas, respectively for 61 Cyg A and B. Considering the high accuracy parallaxes available, these values translate into photospheric radii of R(A) = 0.665 ± 0.005 R and R(B) = 0.595 ± 0.008 R . The new radii constrain efficiently the physical parameters adopted for the modeling of both stars, allowing us to predict asteroseismic frequencies based on our best-fit models. Conclusions. The CESAM2k evolutionary models indicate an age around 6 Gyr and are compatible with small values of the mixing length parameter. The measurement of asteroseismic oscillation frequencies in 61 Cyg A & B would be of great value to improve the modeling of this important fiducial stellar system, in particular to better constrain the masses.

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Section: Introductionsupporting

confidence: 71%

Section: Modeling With Cesam2kmentioning

confidence: 50%

Section: Angular Diameter Discussionmentioning

confidence: 69%

Section: Modeling With Cesam2kmentioning

confidence: 99%

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The radii of the nearby K5V and K7V stars 61 Cygni A & B

Kervella¹,

Mérand

Pichon

et al. 2008

A&A

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“…Thus, here we shall summarize the photographic observations obtained in the above-mentioned program. [14,15], as well as in an article by Gorshanov et al [8]. 14, while in the catalog of Kiselev, et al [15], and the Washington Visual Double Stars Catalog [16] the Pulkovo observations are converted to J2000.0.…”

Section: Observationsmentioning

confidence: 99%

Orbit determination and estimate of the component masses

et al. 2010

Self Cite

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Photographic observations of the visual binary star ADS 7251 were made from 1962 through 2006 on the 26-inch refractor at the Pulkovo Observatory. 206 plates were obtained and used to derive about 3000 relative positions. A uniform series of positions of the B-A components of ADS 7251 with errors in one annual average distance ρ and position angle θ of ±0".006 and ±0 o .02, respectively, have been used to determine the elements of the orbit and the sum of the masses of the components. The orbit has been determined using a method of apparent motion parameters developed at Pulkovo. The positions and motions of the components A and B relative to a system of reference stars have also been calculated from 146 of the plates; this made it possible to determine the position of the center of mass and the ratio of the masses of the components. The masses of A and B are 0.57 ¤ M and 0.53 ¤ M , respectively, a result that is consistent with their spectral classes and does not indicate the presence of significant excess mass.

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The Solar Neighbourhood

Grijs

2011

An Introduction to Distance Measurement in Astronomy

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Observations of the binary star 61 Cyg on the 26 inch refractor at the Pulkovo observatory

Cited by 17 publications

References 9 publications

The radii of the nearby K5V and K7V stars 61 Cygni A & B

The radii of the nearby K5V and K7V stars 61 Cygni A & B

Orbit determination and estimate of the component masses

The Solar Neighbourhood

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