Publication Abstracts

Stothers 1963

Stothers, R., 1963: Variable stars with period greater than 20 days in globular clusters. Astron. J., 68, 242-253, doi:10.1086/108947.

Analysis of irregular, semiregular, and long-period variables in globular clusters is made from published data. Eighty probable cluster members are selected in 31 clusters; the most frequent period is 100 days. Sixteen long-period variables show a period vs maxImum luminosity relation similar to that for variables in the field with a peak around 175 days. The variables in globular clusters are brighter, however, by at least Mpg = 1.5. mag. Their mean luminosity decreases with period. Their light amplitude increases with maximum luminosity and decreases with mean luminosity. Both quantities show much scatter for periods greater than 200 days.

Physical properties of the semiregular and irregular variables show little correlation and resemble both red and yellow types found in the field. For the nine RV Tauri stars among this group, however, the luminosity is maximum at a double penod of 50 days and decreases linearly with increasing period. Amplitude and luminosity decrease with later spectrum. The correlation between amplitude and luminosity is closer for the RV Tauri vanables than for the Irregulars and semiregulars.

Long-period variables with periods greater than around 100 days and RV Tauri stars with long periods seem to occur in clusters where RR Lyrae stars are few or absent. These RR Lyrae poor globular clusters appear to have propertles which are slightly more like those of old galactic clusters than of RR Lyrae rich globular clusters. In agreement with previous work. In galactic clusters, search shows that there are probably no known variables with P>20 days.

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BibTeX Citation

  author={Stothers, R.},
  title={Variable stars with period greater than 20 days in globular clusters},
  journal={Astron. J.},

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RIS Citation

ID  - st08710e
AU  - Stothers, R.
PY  - 1963
TI  - Variable stars with period greater than 20 days in globular clusters
JA  - Astron. J.
VL  - 68
SP  - 242
EP  - 253
DO  - 10.1086/108947
ER  -

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