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Radius of the M giant IRC+00213 Measured for the First Time
Direct measurements of stellar radii regardless of other fundamental
properties are a complex issue of observational astrophysics. The number
of stars available for these measurements is limited due to small angular
sizes of disks and also to technical and methodological difficulties.
The radii considerably vary for different types of stars and are unique for
objects of a certain type. The diameter of the M giant IRC+00213 was
measured at the 6-m BTA telescope of the Special Astrophysical Observatory
of RAS with the method of lunar occultations. Observations were carried out
in the night of April 25-26, 2018 with the speckle interferometer at the 6-m
BTA telescope in the pseudo-continuum region at a wavelength of 694 nm.
This region of the visible spectrum is sparsely populated with titanium-oxide
molecular bands typical of such kind of stars. This shows that the obtained
value is close to photospheric. The measured angular diameter from a model of
a uniformly luminous disk yielded 2,23±0,06 millisecond of arc. It agrees
well with an empirical estimate of 2,14±0,13 millisecond of arc based on
magnitude and color (van Belle, 1999).
Authors:
Dyachenko V.V., Balega Yu.Yu., Beskakotov A.S., Maksimov A.F.,
Mitrofanova A.A., Rastegaev D.A. (SAO RAS), Richichi A.
(Osservatorio Astrofisico di Arcetri, Firenze, Italy).
Published:
1. Dyachenko, V., Richichi, A., Balega, Y., Beskakotov, A.,
Maksimov, A., Mitrofanova, A., & Rastegaev, D. Lunar occultation
observations at the SAO RAS 6-m telescope. 2018. Monthly Notices of
the Royal Astronomical Society, 478(4), pp. 5683-5688.
In detail
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