The Irregular Variable Star V348 Sagittarii.
Abstract
The irregular variable V348 Sagittarii shows recurrent maxima in light, with a mean spacing of about 200 days, at which times the star brightens from m = 17 to about magnitude 11. The rise seems usually to require about days, but the subsequent decline is very much faster. The spectrum near maximum light is peculiar, in that only emission lines of C ii appear in any strength. Weaker features due to He I and [0 II] are also present. The energy distribution in the continuous spectrum is about like that of an F-type star, but no absorption features can be seen with certainty. There is no sign of hydrogen lines in emission or absorption. The radial velocity is variable At minimum, V348 Sgr exhibits the spectrum of a normal gaseous nebula, with emission lines of hydrogen and [0 ii]. The radial velocity is about +210 km/sec. Direct photographs at minimum show the star image as very closely nebulous to a distance of about 1"; a larger and fainter nebulous envelope extends to about 7". The general features of the lightvariation can be explained by the ejection of an opaque shell from the star and its subsequent dissolution. Certain interesting parallels may be drawn between the characteristics of V348 Sgr, which is located in the galactic bulge, and the faint planetary nebulae that are found in such large numbers in the same direction.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1958
- DOI:
- 10.1086/146464
- Bibcode:
- 1958ApJ...127..312H