The Herbig Be star HD 200775, associated with the extended reflection nebulae NGC 7023, has been observed in the ultraviolet with the IUE satellite, in the optical with the 90-cm Schmidt telescope of Campo Imperatore Observatory, and in the infrared with the 2.3 m telescope of Wyoming University in a coordinated campaign made during August 1978. The ultraviolet low-dispersion spectrum shows several strong absorption resonance lines (C II, C IV, Si II, Si IV, Al III . . .) probably formed in an expanding envelope. From the IR observations up to 12.6 microns, a value of the mass loss rate expansion velocity ratio of 2.3 x 10 to the -9th solar masses/year per km/sec is derived. The infrared energy distribution shows also the presence of a dust shell at a mean distance of about 3 x 10 to the 14th cm from the central star. A value of the color excess of 0.25 + or - 0.05 is derived from the 2200-A interstellar band and from the gradient of the UV continuum.
Altamore, A., Baratta G., B., Cassatella, A., Grasdalen G., L., Persi, P., Viotti, R. (1980). Ultraviolet, optical, and infrared observations of the Herbig Be star HD 200775. ASTRONOMY & ASTROPHYSICS, 90, 290-296.
Ultraviolet, optical, and infrared observations of the Herbig Be star HD 200775
ALTAMORE, Aldo;
1980-01-01
Abstract
The Herbig Be star HD 200775, associated with the extended reflection nebulae NGC 7023, has been observed in the ultraviolet with the IUE satellite, in the optical with the 90-cm Schmidt telescope of Campo Imperatore Observatory, and in the infrared with the 2.3 m telescope of Wyoming University in a coordinated campaign made during August 1978. The ultraviolet low-dispersion spectrum shows several strong absorption resonance lines (C II, C IV, Si II, Si IV, Al III . . .) probably formed in an expanding envelope. From the IR observations up to 12.6 microns, a value of the mass loss rate expansion velocity ratio of 2.3 x 10 to the -9th solar masses/year per km/sec is derived. The infrared energy distribution shows also the presence of a dust shell at a mean distance of about 3 x 10 to the 14th cm from the central star. A value of the color excess of 0.25 + or - 0.05 is derived from the 2200-A interstellar band and from the gradient of the UV continuum.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
