Abstract
view Abstract Citations (16) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Cepheid Variable S. Sagittae. II. The Emission Lines. Herbig, George H. Abstract Emission components have been found in the H and K lines of the cepheid variable S Sagittae (P = 8d4, spectral type F6 Ib); they are present for 1.0-1.6 days on the rising branch of the . The bright lines are displaced shortward with respect to Fe I absorption lines by -68km/sec. Proffles have been obtained from a Mount Wilson coud plate; the lines are sharp on their longward edges, but the shortward sides are diffuse. The emission lines shift with the absorption spectrum in the pulsation cycle, and it is clear that they are not associated with the invisible component of the binary system. Intensity measurements on plates of low dispersion (53 A/mm) show that the bright K line appears about 0.6 day after minimum light, increases in strength during the time when it is present, but disappears between 0.5 and 0.9 day before maximum light. These and other facts, as well as a close parallelism with the structure and behavior of the bright Ca II lines observed in long-period variables after maximum light, indicate that the observed emissions are only the shortward wings of broad bright lines that originate low in the atmosphere of S Sagittae, the remainder being obliterated by overlying Ca ii absorption. The shortward displacement of the underlying bright line with respect to the absorption spectrum indicates that the emitting layers are rising. The observed increase of intensity of the emission may be the result of upward motion, except that the weakening of the overlying Ca II absorption line must also act to increase the observed intensity of the emission. Publication: The Astrophysical Journal Pub Date: September 1952 DOI: 10.1086/145620 Bibcode: 1952ApJ...116..369H full text sources ADS | data products SIMBAD (9) Related Materials (1) Part 1: 1952ApJ...116..348H
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call