Scuti Pulsations Research Articles

HR 1170 and HR 7331, two nonradial Delta Scuti pulsators

Multiperiod analysis of the photometry of HR 1170 and HR 7331 by the MFF (multiple-frequency fitting method) yield period ratios of 0.919 and 0.939, respectively, for these stars. These period ratios are consistent with the interpretation of nonradial pulsation in delta Scuti-type stars. Taking these together with the previously known nonradial pulsator, 1 Mon, a linear relation seems to emerge between rotational velocity and period ratio, although the discovery of more nonradial pulsators is necessary in order to firmly establish this relationship.

Metallicism and pulsation : an analysis of the del Del stars.

view Abstract Citations (97) References (77) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Metallicism and pulsation: an analysis of the Delta Delphini stars. Kurtz, D. W. Abstract Fine abundance analyses of eight Delphini stars and one 8 Scuti star relative to four comparison standard stars are presented. Five of the 8 Delphini stars are shown to have abundances most similar to the evolved Am stars. It is argued that these abundances are different from the main-sequence Am star and Ap star abundances, and that similarities to the Ba ii star abundances are coincidental. We suggest that the anomalous-abundance 8 Delphini stars are evolved metallicline stars on the basis of their abundances, position in the (p, Mv) 1?lane, inferred rotation velocities, and perhaps their binary incidence. Some of the 8 Delphim stars are 8 Scuti pulsators. We argue that pulsation and metallicism are mutually exclusive among the classical Am stars but may coexist in other stars related to the classical Am stars. A preference for the diffusibnhypothesis model for the metallic-line stars is stated and supported, and the implications of the coexistence of pulsation and diffusion are discussed. Subject headings: stars: abundances - stars: 8 Scuti - stars: metallic-line - stars: pulsation Publication: The Astrophysical Journal Supplement Series Pub Date: October 1976 DOI: 10.1086/190411 Bibcode: 1976ApJS...32..651K full text sources ADS | data products SIMBAD (15) GCPD (1)

Metallicism, pulsation, and the nature of 32 Virginis

view Abstract Citations (40) References (25) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Metallicism, pulsation, and the nature of 32 Virginis. Kurtz, D. W. ; Breger, M. ; Evans, S. W. ; Sandmann, W. H. Abstract The metallic-line A star 32 Vir has been reported to be a pulsating variable of the Delta Scuti class despite the fact that, in general, Am stars do not pulsate. It also shows a variable line spectrum. The problem of a pulsating Am star with a variable spectrum is investigated by analyzing photometric data and derived abundances for 32 Vir. As a result, both the Delta Scuti pulsation and the classical Am characteristics of 32 Vir are confirmed. The spectrum is shown to be double-lined, rotational velocities are determined for the primary and secondary stars, and the secondary is placed above the observed rotational cutoff for Am stars, suggesting normal abundances. The luminosity ratio of the two components is estimated, their positions on the color-magnitude diagram are plotted, and the predicted pulsation period is compared with the observed period. A model in which the primary is a slowly rotating Am star and the secondary is a rapidly rotating Delta Scuti star is found to fit all the data and to explain all the unusual characteristics of the system. It is concluded that there is no convincing evidence for the pulsation of a single classical Am star. Publication: The Astrophysical Journal Pub Date: July 1976 DOI: 10.1086/154482 Bibcode: 1976ApJ...207..181K Keywords: A Stars; Binary Stars; Metallic Stars; Stellar Models; Stellar Spectrophotometry; Abundance; Color-Magnitude Diagram; Light Curve; Radial Velocity; Stellar Rotation; Ubv Spectra; Astrophysics full text sources ADS | data products SIMBAD (10)