Results 1 to 10 of about 4,933 (118)
The Three Dimensional Structure of EUV Accretion Regions in AM Herculis Stars: Modeling of EUV Photometric and Spectroscopic Observations [PDF]
The Astrophysical Journal, 1998 We have developed a model of the high-energy accretion region for magnetic cataclysmic variables and applied it to {\it Extreme Ultraviolet Explorer} observations of 10 AM Herculis type systems. The major features of the EUV light curves are well described by the model.
Sirk, Martin M., Howell, Steve B.
core +7 more sources
Optical Studies of 8 AM Herculis-Type Cataclysmic Variable Stars [PDF]
The Astronomical Journal, 2020 We report detailed follow-up observations of 8 cataclysmic variable stars (CVs) that are apparently AM Her stars, also called polars. For all, we either determine orbital periods for the first time, or improve on existing determinations. The seven for which we have spectra show the high-amplitude radial velocity curves and prominent HeII 4686 emission ...
Thorstensen, John R. +4 more
semanticscholar +5 more sources
The Unusual UV Spectra of EUV-Discovered AM Herculis Stars [PDF]
International Astronomical Union Colloquium, 1996 International Ultraviolet Explorer observations of the ROSATWFC-discovered AM Hers RE2107–05, RE1938–46, RE1833–74, RE1149+28, and RE0751+14 reveal UV spectra (1200 – 2000 Å) which are unique when compared with previously studied systems. Specifically, the intensities of individual emission lines due to CIV, CII, N V, HeII, and Si IV, are 2 – 4 times ...
Adrienne E. Herzog +2 more
openaire +2 more sources
A survey for QPOs in AM Herculis stars and a detailed study of the QPOs in AN Ursae Majoris [PDF]
Monthly Notices of the Royal Astronomical Society, 1993 We have searched for quasi-periodic oscillations with frequencies between 0.1 and 2.4 Hz in the light curves of nine AM Her stars using simultaneous multi-colour photometry. Oscillations were not seen in BY Cam (=H 0538+608), EF Eri, AM Her, DP Leo (=E 1114+182), ST LMi (=CW 1103+254), MR Ser (=PG 1550+191) or QQ Vul (=E 2003+225), but were detected in
Tod F. Ramseyer +4 more
openaire +2 more sources
High and low states of the system AM Herculis [PDF]
Astronomy and Astrophysics, 2008 Context: We investigate the distribution of optically high and low states of the system AM Herculis (AM Her). Aims: We determine the state duty cycles, and their relationships with the mass transfer process and binary orbital evolution of the system.
Bailey +35 more
exaly +3 more sources
Keplerian disks and outflows in post-AGB stars: AC Herculis, 89 Herculis, IRAS 19125+0343, and R Scuti [PDF]
Astronomy and Astrophysics, 2021 There is a class of binary post-AGB stars with a remarkable near-infrared excess that are surrounded by Keplerian or quasi-Keplerian disks and extended outflows composed of gas escaping from the disk.
Javier Alcolea, H Van Winckel
exaly +2 more sources
Bowen fluorescence in AM Herculis stars
The Astrophysical Journal, 1991 The study relates the observations of the Bowen fluorescence lines in AM Her and EF Eri, two AM Her systems. The implications of source variability and the checks performed in order to verify the accuracy of the data are reviewed. The line ratios for H I and He II are shown to deviate considerably from those expected; in this light, the H I and He II ...
Jonathan Schachter +3 more
openaire +2 more sources
AM Herculis Type Stars - Magnetic Binaries [PDF]
International Astronomical Union Colloquium, 1977 A new class of close binary stars, proposed to be called polars, has been discovered during recent year; its prototype is AM Her. The three known polars, AM Her, AN UMa, and W Pup, are polarization, spectrum, radial velocity, optical, and infrared variables of short periods of 3.1, 1.9, and 1.7 hours, respectively (Tapia 1977 a, b, c; Michalsky et al ...
W. Krzemiński
openaire +2 more sources
Indirect imaging of AM Herculis-stars
, 2005 AM Herculis-Sterne sind enge Doppelsterne, die aus einem weißen Zwerg mit starkem Magnetfeld und einem Hauptreihenstern bestehen. Letzterer verliert Materie an den weißen Zwerg, wobei das Magnetfeld die Materie zu den Magnetpolen leitet, wo die freigesetzte potentielle Energie abgestrahlt wird hauptsächlich als Röntgen- und UV-Strahlung.
A. Staude
semanticscholar +5 more sources
The Cyclotron Lines in the Optical Spectra of the Stars of AM Herculis Group: Observations and Interpretation [PDF]
Symposium - International Astronomical Union, 1980 The stars of the AM Herculis group (AM Her, VV Pup, AN UMa and 2A 0311-227) are close binaries containing a mass losing, nondegenerate star and an accreting degenerate dwarf. Their main properties are: the large linear and circular polarization of the optical light, high and low luminosity states, the variable emission line, spectra of H, He and other ...
I. Mitrofanov
openaire +2 more sources