Naslov
The quiescent phase of CH Cygni during the period 1987-1989

Autori
Kotnik-Karuza, Dubravka ; Jurdana, Rajka ; Hack, Margherita

Izvornik
Astronomy and astrophysics. Supplement series (0365-0138) 94 (1992); 251-255

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
stars: binaries: symbiotics - stars; CH Cygni

Sažetak
The optical spectrum of the symbiotic star CH Cygni has been investigated during the period 1987-1989 following the end of the long lasting outburst of 1977-1986. The measurements of the radial velocities of the unblended spectral lines have shown that the envelope is still expanding, that the absorption lines of both neutral and once ionized elements are formed in the photosphere of the M6 III star, and that the emission lines including the Balmer lines, some forbidden lines and permitted Fe II lines show radial velocities roughly opposite in phase with respect to the photospheric ones, as they did during the previous outbursts ; therefore they can be associated with the companion. The complete disappearance of the blue continuum has been proved. The two absorption components of the Ca II H and K lines show about the same radial velocities as during the last outburst indicating the presence of two expanding almost permanent envelopes.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA