Results 131 to 140 of about 6,703 (158)

Coordinated observations of the red dwarf flare star EV LAC in 1994 and 1995

Astronomical & Astrophysical Transactions, 1998
Abstract The results of photometric, spectral and radio studies of the flare star EV Lac we obtained during the course of cooperative observations in 1994 and 1995 are presented. A quantitative analysis of the radiation emitted by two powerful flares using the colour-colour diagram confirms the previous conclusion on the essential heterogeneity of ...
E. P. Abranin, I. Yu. Alekseev, S. Avgoloupis, L. L. Bazelyan, S. V. Berdyugina, G. Cutispoto, R. E. Gershberg, V. M. Larionov, G. Leto, V. N. Lisachenko, G. Marino, L. N. Mavridis, S. Messina, V. N. Mel'nik, I. Pagano, S. V. Pustil'nik, M. Rodonò, G. Sh. Roizman, J. H. Seiradakis, G. P. Sigal, N. I. Shakhovskaya, D. N. Shakhovskoy, V. A. Shcherbakov   +22 more
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ENVIRONMENTAL EFFECTS OF FLARES FROM RED DWARF STARS

International Journal of Modern Physics E, 2011
We examine some environmental effects appearing on exoplanets in the habitable zone of red dwarfs, during the first billion years of the star evolution. We focus on the radiative perturbation that the frequent stellar flares would cause on the planet surface and down the assumed planetary ocean, with some insight on the affectation of potential life ...
LIUBA PEÑATE, ROLANDO CÁRDENAS, OSMEL MARTÍN   +2 more
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Emission lines of the red-dwarf flare star EV Lac: Stellar flares

Astronomy Reports, 2001
We present equivalent widths and profiles for Hα Hβ, Hγ and He I λ4471 A emission lines obtained in observations of the flares of EV Lac made at the Crimean Astrophysical Observatory in 1994 and 1995. Our semi-empirical modeling of the flares gives insight into the structure of the emitting regions, including a temperature plateau, and also into the ...
É. A. Baranovskii, R. E. Gershberg, D. N. Shakhovskoi   +2 more
openaire   +1 more source

Interferometric observations of weak radio flares from a red dwarf star

Nature, 1978
MEASUREMENT of the radio emission associated with flares on M-type red dwarf stars has been difficult because of the sporadic and transient nature of the phenomena, and the danger of confusion with terrestrial sources of emission. The existence of detectable radio emission from the flares was first established by integration and correlation with the ...
R. J. DAVIS, BERNARD LOVELL, H. P. PALMER, R. E. SPENCER   +3 more
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Coordinated Observations of the Red Dwarf Flare Star EV Lac in 1993

Astrophysics and Space Science, 1997
Results of cooperative observations of the flare star EV Lac in September 1993 are presented. One of the about 30 optical flares detected was powerful enough to permit a quantitative analysis of its intrinsic radiation with the colour-colour technique.
E.P. Abranin, L.L. Bazelyan, I.Yu. Alekseev, R.E. Gershberg, S. Avgoloupis, J.H. Seiradakis, L.N. Mavridis, G.M. Beskin, S.N. Mitronova, I.P. Panferova, M.R. Kidger   +10 more
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Flaring red dwarf stars: news from Crimea

Uspekhi Fizicheskih Nauk, 1998
Important phenomena are briefly described which have recently been discovered in the Crimean studies of flaring red dwarf stars believed to be the most common type of variable stars in the Galaxy. These phenomena include (i) long-lived radiation from a blueshifted component in the ionized-helium λ 4686 A emission line in the active state of one such ...
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Spectral observations of red dwarfs II. New observations of flare stars in the Pleiades cluster region

Astrophysics, 1994
We studied the spectra of 24 flare stars of the Pleiades cluster region obtained on the 2.6m telescope of the Byurakan observatory in the years 1986–1989. From the spectral indices of titanium oxide (TiO) and other chemical elements of the stars investigated we determined their spectral classes and luminosities (absolute visual stellar magnitudes). The
L. V. Mirzoyan, V. V. Ambaryan, A. T. Garibdzhanyan   +2 more
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Investigation of flare activity of the red dwarf star EV Lac based on original observations and using the data from ground-based and space surveys

2022
The problem of energetics of flare activity of dwarf stars in the lower main sequence of the Hertzsprung-Russell diagram is relevant in the context of the detection of powerful flares (superflares) and the possibility of assessing such phenomena on the Sun in the past and future. A brief historical review of the EV Lac original researches is presented,
Shlyapnikov, A.A., Gorbachev, M.A.
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Emission lines in the spectrum of the red-dwarf flare star EV Lac: Modeling of the quiescent chromosphere

Astronomy Reports, 2001
We present spectral observations of the red-dwarf flare star EV Lac made at the Crimean Astrophysical Observatory in 1994 and 1995, and describe a method for semi-empirical modeling of the chromospheres of red dwarfs based on their emission spectra.
E. A. Baranovskii, R. E. Gershberg, D. N. Shakhovskoi   +2 more
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Coordinated observations of the red dwarf flare star EV Lac in 1998

2019
The results of photometric studies of the flare star EV Lac obtained in the course of cooperative observations in 1998 are presented. No significant brightness variations in IR were found from simultaneous observations of the star in UBVRI and H bands, in coincidence with the observed optical flares.
Alekseev, I.Yu., Antov, A.P., Avgoloupis, S.J., Beskin, G.M., Borisov, N.V., Chalenko, V.E., Contadakis, M.E., Gershberg, R.E., Khalak, V.R., Konstantinova-Antova, R.K., Larionov, V.M., Panferova, I.P., Plokhotnichenko, V.L., Pustil???nik, L.A., Romanyuk, Ya.O., Seiradakis, J.-H., Sergeev, S.G., Svyatogorov, O.A., Verlyuk, I.A., Zhilyaev, B.E.   +19 more
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