Results 11 to 20 of about 6,703 (158)

Chromospheric lines in red dwarf flare stars. II - EV Lacertae EQ Pegasi A, and V1054 Ophiuchi

The Astrophysical Journal, 1984
On presente des observations de profils de raies avec une resolution spectrale de 0,45 A pour trois etoiles M4e semblables, du voisinage solaire, avec une luminosite de 1/60 du Soleil: EV Lacertae, EQ Pegari A et V 1054 Oph. On donne des resultats pour Hα (λ6563), les raies Na D(λλ5890, 5896), He I (λ5876) et les raies triplet infra-rouge Ca II (λλ8498,
B. R. Pettersen, L. A. Coleman, D. S. Evans   +2 more
openaire   +3 more sources

Narrow-band radio flares from red dwarf stars

The Astrophysical Journal, 1986
VLA observations of narrow-band behavior in 20 cm flares from two red dwarf stars, L726 - 8A and AD Leo, are reported. The flare on L726 - 8A was observed at 1415 and 1515 MHz; the flux and the evolution differed significantly at the two frequencies. The flare on AD Leo lasted for 2 hr at 1415 MHz but did not appear at 1515 MHz.
Stephen M. White, Mukul R. Kundu, Peter D. Jackson   +2 more
openaire   +1 more source

DE Canum Venaticorum : a bright, eclipsing red dwarf–white dwarf binary [PDF]

, 2007
Context. Close white dwarf–red dwarf binaries must have gone through a common-envelope phase during their evolution. DE CVn is a detached white dwarf–red dwarf binary with a relatively short (∼8.7 h) orbital period.
Bergeron, Bergeron, Brinkworth, Bruch, D. D. Balam, de Jager, de Jager, de Kool, de Kool, Dehnen, Dewi, Dhillon, E. J. M. van den Besselaar, E. W. Guenther, Eggleton, Fuhrmann, G. Nelemans, Green, Haefner, Holmes, Hurley, J. Kemp, J. R. Thorstensen, Johnson, King, Kirkpatrick, L. Morales-Rueda, Marsh, Maxted, Monet, Morales-Rueda, Nelemans, O'Donoghue, P. J. Groot, Paczynski, Panei, Pickles, R. Greimel, R. M. Robb, Reid, Robb, Schreiber, Smith, T. Augusteijn, T. R. Marsh, Taam, Tas, V. S. Dhillon, Verbunt, Verbunt, Voges, Wesemael   +51 more
core   +4 more sources

PHOTOMETRIC STUDY ON STELLAR MAGNETIC ACTIVITY. I. FLARE VARIABILITY OF RED DWARF STARS IN THE OPEN CLUSTER M37 [PDF]

The Astrophysical Journal, 2015
28 pages, 21 figures, 7 tables, Accepted for publication in ...
S.-W. Chang, Y.-I. Byun, J. D. Hartman
openaire   +3 more sources

High Time Resolution Photometry of Red Dwarf Flare Stars III. The Most Rapid and Faintest Observed Stellar Flares; their Physics and Statistics [PDF]

International Astronomical Union Colloquium, 1989
AbstractHigh time resolution monitoring of the UV Cet type flare stars has enabled as to detect flares with total duration of a few seconds and with energy output comparable to solar subflares. We find that the time scales of decay for such flares correspond to recombination times of optically thin gas or to cooling times of optically thick gas heated ...
G.M. Beskin, S.I. Neizvestnyj, V.L. Plakhotnichenko, L.A. Pustil'nik, V.F. Shvartsman, R.E. Gershberg   +5 more
openaire   +1 more source

EvryFlare II: Rotation Periods of the Cool Flare Stars in TESS Across Half the Southern Sky [PDF]

, 2020
We measure rotation periods and sinusoidal amplitudes in Evryscope light curves for 122 two-minute K5-M4 TESS targets selected for strong flaring. The Evryscope array of telescopes has observed all bright nearby stars in the South, producing two-minute ...
Corbett, Hank, del Ser, Daniel, Fors, Octavi, Galliher, Nathan, Glazier, Amy, Haislip, Joshua, Howard, Ward S., Law, Nicholas M., Ratzloff, Jeffrey K.   +8 more
core   +3 more sources

High Time Resolution Photometry of Red Dwarf Flare Stars I. A Search For Fine Structures on the Optical Light Curves of Flares [PDF]

International Astronomical Union Colloquium, 1989
AbstractA detailed analysis of 73 flares on UV Cet type stars observed at the 6 m telescope of the Special Astrophysical Observatory with 3x10–7 s time resolution shows no fine structures on flare light curves with time scales from 10–6 to 10–1 s.
G.M. Beskin, S.N. Mitronova, S.I. Neizvestnyj, V.L. Plakhotnichenko, L.A. Pustil'nik, V.F. Shvartsman, R.E. Gershberg   +6 more
openaire   +1 more source

Galactic cosmic rays on extrasolar Earth-like planets: II. Atmospheric implications

, 2016
(abridged abstract) Theoretical arguments indicate that close-in terrestial exoplanets may have weak magnetic fields. As described in the companion article (Paper I), a weak magnetic field results in a high flux of galactic cosmic rays to the top of the ...
Atri, D., Grenfell, J. L., Grießmeier, J. --M., Stadelmann, A., Tabataba-Vakili, F.   +4 more
core   +6 more sources

A magnetic accretion switch in pre-cataclysmic binaries [PDF]

, 2014
We have investigated the mass accretion rate implied by published surface abundances of Si and C in the white dwarf component of the 3.62 h period pre-cataclysmic binary and planet host candidate QS Vir (DA+M2−4).
Almeida, Andronov, Applegate, Baliunas, Bilíková, Boris Gaensicke, Brown, Büning, Cecilia Garraffo, Cohen, Dai Takei, Debes, Drake, Dupuis, Hessman, Horner, Jeremy J. Drake, Jura, Kawaler, Kawka, Kilkenny, Knigge, Koester, Kopal, Livio, Long, Matranga, Mestel, O'Donoghue, Oláh, Paczynski, Pandel, Paquette, Parsons, Parsons, Podsiadlowski, Pyrzas, Qian, Ribeiro, Ritter, Savanov, Schmidt, Schmidt, Schwope, Shara, Sills, Sion, Tappert, Townsley, Verbunt, Vogel, Warren, Weber, Yashiro, Zorotovic   +54 more
core   +2 more sources

Flares on Red Dwarf Stars as a Result of the Dynamical Response of the Chromosphere to the Heating [PDF]

International Astronomical Union Colloquium, 1983
The impulsive hard X-ray, EUV and microwave radio bursts always start at or after the onset of a soft X-ray increase - the main phase of a solar flare - before the Hα flare maximum. This hard phase of a solar flare lasts ~ 100 s and consists of several elementary bursts of 10 s duration.
M.M. Katsova, M.A. Livshits
openaire   +1 more source