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A HST study of the stellar populations in the cometary dwarf irregular galaxy NGC 2366
- Publication Year :
- 2005
-
Abstract
- We present V and I photometry of the resolved stars in the cometary dwarf irregular galaxy NGC 2366, using Wide Field Planetary Camera 2 images obtained with the Hubble Space Telescope. The resulting color-magnitude diagram reaches down to I~26.0 mag. It reveals not only a young population of blue main-sequence stars (age 100 Myr) and red giant branch (RGB) stars (age >1 Gyr). The measured magnitude I=23.65+/-0.10 mag of the RGB tip results in a distance modulus m-M=27.67+/-0.10, which corresponds to a distance of 3.42+/-0.15 Mpc, in agreement with previous distance determinations. The youngest stars are associated with the bright complex of HII regions NGC 2363=Mrk 71 in the southwest extremity of the galaxy. As a consequence of the diffusion and relaxation processes of stellar ensembles, the older the stellar population is, the smoother and more extended is its spatial distribution. An underlying population of older stars is found throughout the body of NGC 2366. The most notable feature of this older population is the presence of numerous relatively bright AGB stars. The number ratio of AGB to RGB stars and the average absolute brightness of AGB stars in NGC 2366 are appreciably higher than in the BCD VII Zw 403, indicating a younger age of the AGB stars in NGC 2366. In addition to the present burst of age<br />Comment: 32 pages, 15 figures, accepted for publication in the Astrophysical Journal
- Subjects :
- Physics
education.field_of_study
Stellar population
Star formation
Astrophysics::High Energy Astrophysical Phenomena
Population
Astrophysics (astro-ph)
FOS: Physical sciences
Astronomy and Astrophysics
Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
Galaxy
Red-giant branch
Distance modulus
Stars
Space and Planetary Science
Astrophysics::Solar and Stellar Astrophysics
Astrophysics::Earth and Planetary Astrophysics
Irregular galaxy
education
Astrophysics::Galaxy Astrophysics
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....5d2b287a09a4a7bbe3f269e8cd3f386b