• Title/Summary/Keyword: RR Lyrae

Search Result 53, Processing Time 0.02 seconds

VARIABLE STARS IN THE REGION OF THE OPEN CLUSTER NGC 457 (산개성단 NGC 457 영역의 변광성)

  • Jeon, Young-Beom;Park, Yoon-Ho;Lee, Sang-Min
    • Publications of The Korean Astronomical Society
    • /
    • v.32 no.3
    • /
    • pp.421-438
    • /
    • 2017

  • Through the short-period variability survey program, we obtained time-series BV CCD images for $1.5^{\circ}{\times}1.0^{\circ}$ region around the young open cluster NGC 457. As a result, we have detected 61 variable stars including 31 new ones after checking light curves of all stars by eyes. The 61 variable stars were included 14 ${\delta}$ Scuti variable stars, a ${\beta}$ Cephei variable star, 10 variable Be and slowly pulsating B stars, 13 eclipsing binary stars, 21 semi-long periodic or slow irregular variables and an RR Lyrae variable star, respectively. Many variable B-type stars were known through a well-defined zero-age main sequence to the ${\beta}$ Cepheid region of NGC 457. Most of the variable B-type stars found this paper were known variable stars. But, 11 out of 14 ${\delta}$ Scuti variable stars were newly discovered. The new variable stars except for ${\delta}$ Scuti stars were 4 variable B-type stars, 5 eclipsing binaries and 11 semi-long periodic or slow irregular variables. We have performed frequency analysis for all ${\delta}$ Scuti stars, a ${\beta}$ Cepheid star and an RR Lyrae star.

  • https://doi.org/10.5303/PKAS.2017.32.3.421 인용 PDF KSCI

DETERMINATION OF PHYSICAL QUANTITIES OF GLOBULAR CLUSTERS

  • Kim, Kang-Min;Lee, See-Woo
    • Journal of The Korean Astronomical Society
    • /
    • v.22 no.2
    • /
    • pp.81-99
    • /
    • 1989

  • Applying five morphological parameters defined along the main sequence (MS), red giant branch (RGB) and horizontal branch (HB) in the C-M diagram (CMD), and the transition period-luminosity relation for RR Lyrae variables, some basic physical quantities such as helium abundance, age, mass and luminosity are determined for 21 well observed globular clusters with combination of evolutionary models and atmospheric models properly chosen by the numerical test. The dependences of these quantities on the age and chemical abundance are investigated.

  • PDF