From Einstein Observatory, we know most nearby dM flare stars have X-ray emissions. X-ray flare energy of dM stars is far larger than that of large flares of sun. The corona temperature of dM stars is higher than that...From Einstein Observatory, we know most nearby dM flare stars have X-ray emissions. X-ray flare energy of dM stars is far larger than that of large flares of sun. The corona temperature of dM stars is higher than that of sun. The X-ray flare time scales are several minutes to hours. Star corona heating model for X-ray flares is loop model, which provide a mechanism to convert magnetic energy to heat energy in star corona.Within identification of ROSAT X-ray sources, we found that X-ray source: RX1102.0+4347 corresponds to WX UMa, a dM5e flare star, which is in a nearby visual binary: Gliese 412A+B. The binary is very near to earth, 5.38pc, and has high proper motion, 4'.54/ year. The binary is also an Einstein X-ray source: 1 E1103.0+4346.In March 27, 1993, we observed WX UMa by CCD BVRI photometry at BAO 2.16m telescope. Magnitudes of the star are: V = 14.56, B-V = 1.95, V-R = 0.97, R-I = 2.06, which are similar to previous observations.From the ROSAT X-ray survey data in November 7-17, 1990, average展开更多
The pointed observations of NGC3077 are analyzed by position sensitive proportional counter (PSPC) on board the ROSAT satellite on 1991-04-18, 1991, finding out that the X-ray emission range of M81 galaxy has, in the ...The pointed observations of NGC3077 are analyzed by position sensitive proportional counter (PSPC) on board the ROSAT satellite on 1991-04-18, 1991, finding out that the X-ray emission range of M81 galaxy has, in the softer and more sensitive ROSAT PSPC band (0. 2-2. 4 keV), extended by 40% larger than ever observed by image proportional counter (IPC) on board the Einstein satellite, which shows that M81 galaxy has a larger X-ray corona. And by the aid of the timing analysis, it is concluded that M81 nucleus has no variabilities on time scale of a few minutes; hence the possibility of M81 nucleus having the marginal variability over time scale of about 2 min that Fabbiano (1988) found from the Einstein IPC observation is ruled out.展开更多
文摘From Einstein Observatory, we know most nearby dM flare stars have X-ray emissions. X-ray flare energy of dM stars is far larger than that of large flares of sun. The corona temperature of dM stars is higher than that of sun. The X-ray flare time scales are several minutes to hours. Star corona heating model for X-ray flares is loop model, which provide a mechanism to convert magnetic energy to heat energy in star corona.Within identification of ROSAT X-ray sources, we found that X-ray source: RX1102.0+4347 corresponds to WX UMa, a dM5e flare star, which is in a nearby visual binary: Gliese 412A+B. The binary is very near to earth, 5.38pc, and has high proper motion, 4'.54/ year. The binary is also an Einstein X-ray source: 1 E1103.0+4346.In March 27, 1993, we observed WX UMa by CCD BVRI photometry at BAO 2.16m telescope. Magnitudes of the star are: V = 14.56, B-V = 1.95, V-R = 0.97, R-I = 2.06, which are similar to previous observations.From the ROSAT X-ray survey data in November 7-17, 1990, average
文摘The pointed observations of NGC3077 are analyzed by position sensitive proportional counter (PSPC) on board the ROSAT satellite on 1991-04-18, 1991, finding out that the X-ray emission range of M81 galaxy has, in the softer and more sensitive ROSAT PSPC band (0. 2-2. 4 keV), extended by 40% larger than ever observed by image proportional counter (IPC) on board the Einstein satellite, which shows that M81 galaxy has a larger X-ray corona. And by the aid of the timing analysis, it is concluded that M81 nucleus has no variabilities on time scale of a few minutes; hence the possibility of M81 nucleus having the marginal variability over time scale of about 2 min that Fabbiano (1988) found from the Einstein IPC observation is ruled out.
