Spectrophotometric observations of variable stars

Ruban, E. V.; Alekseeva, G. A.; Arkharov, A. A.; Hagen-Thorn, E. I.; Галкин, В. Д.; Nikanorova, I. N.; Новиков, В. В.; Pakhomov, V. P.; Puzakova, T. Yu.

doi:10.1134/s1063773706090052

Cited by 9 publications

(12 citation statements)

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“…This assumption is confirmed by spectrophotometric measurements [10,11]. According to those measurements, no deviations from a normal distribution were found in the energy curves for the star-component system (the component was not resolved), which indicates that the component belongs to the same (or to a close) spectral class as the principal star, specifically, to class M. This assumption was made in the earlier work of Ref.…”

Section: Influence Of External Factorssupporting

confidence: 51%

Microvariability and fast variability of stars. II. The semiregular red giants L2 Pup, 2 Cen, η Gem, and σ Lib

Ruban

Arkharov

2010

Astrophysics

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and σ Lib, from the Hipparcos catalog to search for microvariability and rapid variations in their emission. It is shown that low amplitude variability shows up in the form of rapid changes in the brightness minimum of the main cycle. The magnitudes of 2 Cen and σ Lib changed by 0 m .10-0 m .15 over 15-20 min. These variations were repeated over time intervals that were multiples of 150-180 min. The spread in the magnitudes of L 2 Pup was 0 m .02-0 m .06 over days. Rapid bursts with brightness increases of up to ~0 m .1 within seconds, over time intervals of <21 min, were observed in η Gem. These bursts could, presumably, be induced by a hypothetical nearby satellite upon its closest approach to the star. Then the orbital period of the satellite is equal to the period of the star's pulsations.The existence of such a satellite requires further confirmation.

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Section: Influence Of External Factorssupporting

confidence: 51%

Microvariability and fast variability of stars. II. The semiregular red giants L2 Pup, 2 Cen, η Gem, and σ Lib

Ruban

Arkharov

2010

Astrophysics

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“…For each observation number N, Table 2 lists the quasimonochromatic magnitudes [4] λ m of the star in the real continuum (see Fig. 1) at four wavelengths λ.…”

Section: Light Curvesmentioning

confidence: 99%

“…However, a brightness maximum on the date λ m stands out distinctly for both bands in this figure. Taking this date as an initial reference date and using a period of 12.0 d [2] for the period of the brightness variation, it is possible to distribute the data over cycles, calculating the dates of the expected maxima within the time of the observations [4,8] and determine the phases ph in both series for each observation. the more precise values of Vt from the Hipparcos catalog [8].…”

Section: Light Curvesmentioning

confidence: 99%

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Physical parameters of the semiregular variable red giant 2 Cen

et al. 2009

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This is a study of photometric data from the Hipparcos catalog and spectrophotometric observations by a group of Pulkovo observers in Bolivia of the variable star 2 Cen (V806 Cen). Fourier analysis yields a more precise value of 12.57 d for the period of the brightness variation instead of 12.0 d. Light curves constructed from the photometric data are found to have a smooth systematic variation with an amplitude on the order of 0 m .2. Short duration changes in the brightness by 0 m .1 take place over times of a fewhours. The differences in the temperature and radius of the emitting layer at maximum and minimum brightness, which occur at phases of 0.00 and 0.58, respectively, are found. At the maximum the radius was smaller by 6% and the temperature was higher by 70 K; these differences may characterize the star's pulsations.

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“…Another three SR type stars from a spectrophotometric catalog [2,3] are brought into the study: L 2 Pup, η Gem and σ Lib. (A study of the spectrophotometric variability of L 2 Pup has been reported previously [4].)…”

Section: Introductionmentioning

confidence: 99%

Microvariability and fast variability of stars. I. standard stars

Ruban

Архаров

2010

Astrophysics

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This is a study of observations of the photometric quantities Vt andBt, reported in the Hipparcos catalog, for 15 standard stars in order to search for microvariability and rapid variability in their emission. The microvariability is found to be characterized mainly by smooth fluctuations in the brightness. Changes in the magnitudes of the stars HD 28355 and HD 130109 with a period of ~150 min and an amplitude <0 m .02 appear to be caused by vertical shifts in their photospheres. Changes in the magnitudes with an amplitude of ~0 m .01 and a period of 11.4 d in the star e Eri were related to the rotation of spots. A similar microvariability period and amplitude in the star 51 Peg most likely originates in the influence of a planet.

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Spectrophotometric observations of variable stars

Cited by 9 publications

References 1 publication

Microvariability and fast variability of stars. II. The semiregular red giants L2 Pup, 2 Cen, η Gem, and σ Lib

Microvariability and fast variability of stars. II. The semiregular red giants L2 Pup, 2 Cen, η Gem, and σ Lib

Physical parameters of the semiregular variable red giant 2 Cen

Microvariability and fast variability of stars. I. standard stars

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