Semiregular Red Variables with High Velocities and Balmer Emission.

Abstract

view Abstract Citations (3) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Semiregular Red Variables with High Velocities and Balmer Emission. Keenan, Philip ; Young, Warren Abstract Spectrograms taken for the classification of red variable stars revealed one, CZ Del, which has one of the largest radial velocities yet observed for a semi- regular variable of class SRb (and spectral type M or S). In the General Catalogue of Kukarkin and Parenago the SRb variables are defined as roughly periodic, with small amplitudes, and having the mean luminosities of ordinary giants as distinguished from the supergiant variables of group SRc. Very few of them have large space motions, only two having published radial velocities in excess of 100 km/sec. Radial velocities have been measured on Coude' spectrograms of CZ Del and KN Aql (Vr = -140 km/sec in Mount Wilson Catalogue) taken at the Palomar Observatory in August 1963. Velocities determined from the stellar lines and the interstellar D2 line are: No. Inter- of stellar Spectrum V~(km/sec) V~' lines V KNAql M5.5e -149.3+0.7 -138 14 -15.2 CZDel MSe -162.0+0.5 -150.5 72 -8.8 Vr' is the peculiar radial velocity, assuming the basic solar motion. Both stars lie near the direction of galactic rotation, and the large negative velocities are to be expected if the stars belong to the high-velocity population. Both KN Aql and CZ Del showed variable Balmer emission which sometimes disappears but in 1963 was quite strong. Emission had not previously been reported in CZ Del. The third of the high-velocity SRb variables, V UMi, has been observed extensively in the past without showing noticeable emission lines. Balmer emission is less common in stars of group SRb than in SRa variables, which are intermediate in several characteristics between normal semiregular variables and Mira stars. Our results suggest that the SRb variables with high-velocities tend to resemble SRa variables in physical characteristics. Perhaps the semiregular variables with fairly strong Balmer emission should be grouped together in one class. We are indebted to the National Science Foundation for its support, and to the Mount Wilson and Palomar Observatories for the Coude' observing time. Publication: The Astronomical Journal Pub Date: 1964 DOI: 10.1086/109451 Bibcode: 1964AJ.....69R.546K full text sources ADS | data products SIMBAD (3)