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The evolution status of HD 104237, ɛ Cha and HD 100546.

Hu, Jingyao; Shen, Chuanjian

Using the new data from Hipparcos and the TD-1 UV data, the authors fix the positions of three objects, HD 104237, HD 100546 and ɛ Cha in the HR diagram and discuss their theoretical evolutionary status.

Galactic kinematics derived from classical Cepheids.

Zhu, Zi

On the basis of radial velocity and Hipparcos proper motion data, the author has analyzed the galactic kinematics of classical Cepheids. Using the 3-D Ogorodnikov-Milne model he has determined the rotational velocity of the Galaxy to be V₀ = 240.5±10.2 km/s, on assuming a galactocentric distance of the Sun of R₀ = 8.5 kpc. Th…

The mass and angular momentum loss from the edge of the accretion disc and the evolution of cataclysmic binaries.

Yu, K. N.; Huang, Runqian

The IUE observations of high excitation P Cygni profiles provide evidence that there is mass outflow in the cataclysmic variables with speed of ≡5000 km/s which can not be driven by the late-type secondary stars. The authors proposed here that these outflows are originated from the outer edge of the accretion disc and give a model for calculation …

Analysis of COS-B and HEAO-B satellite data of the pulsar Geminga

Song, Li-Ming; Wu, Mei; Ma, Yu-Qian +4 more

Timing and spectral analysis of COS-B and HEAO-B satellite data of the pulsar Geminga are presented. The results confirm that Geminga is a pulsar with a strong gamma emission and a weak X-ray emission. A phase histogram of Geminga in different energy ranges from a summation of four COS-B observations is given.

Geminga pulsar in COS-B and HEAO-B observations.

Sun, X.; Ma, Y.; Li, T. +4 more

PSR 1820-11: a binary gamma-ray pulsar.

Li, Ti-Pei; Wu, Mei

Significant pulsation structure in the phase distribution of 50 - 6000 MeV gamma-rays from the direction of the binary radio pulsar PSR 1820-11 in the COS-B data was obtained by the folding algorithm. Besides period searches, a spatial analysis was performed and a clear point-like image at the pulsar's position for gamma-rays above 50 MeV was obta…

Pulsed gamma-rays from PSR 1951 + 32

Li, Ti-Pei; Wu, Mei; Ma, Yu-Qian +1 more

In a previous paper [1] we obtained statistically significant evidence for a 39-ms period in the COS-B data of 30-5000 MeV gamma rays in the direction of PSR 1951 + 32. Most of the gamma photons from PSR 1951 + 32 are pulsed and concentrated in a narrow interval of phase. We have examined the partical distribution of gamma ray intensity in the reg…