“School of Astronomy”

Back to Papers Home
Back to Papers of School of Astronomy

Paper   IPM / Astronomy / 14344
School of Astronomy
  Title:   Star Formation History and Dust Production: NGC147 and NGC185
1.  R. Golshan
2.  A. Javadi
3.  J.Th. van Loon
4.  H.G. Khosroshahi
  Status:   Published
  Journal: Journal of The Korean Astronomical Society
  No.:  3
  Vol.:  30
  Year:  2015
  Pages:   169-171
  Supported by:            ipm IPM
NGC 147 and NGC 185, paired satellites of the Andromeda galaxy, possess the same order of mass and analogous structures, but they show different star formation and different amounts of interstellar gas and dust. Therefore, we present the first reconstruction of the star formation history of NGC 147 and NGC 185. Asymptotic Giant Branch stars are highly evolved stars that are brightest in K-band. This maximum K-band magnitude is related to the birth mass of stars. As a result, we have found a 9.9 Gyr old single star formation epoch for NGC 185 followed by relatively continuous star formation. NGC 147, however, has passed through two star formation episodes; one is as old as �?�6 Gyr and the other is as recent as �?�850 Myr. Asymptotic Giant Branch stars are also important dust factories; by fitting Spectral Energy Distributions to observed near and mid infrared data for each star, we were able to measure the dust production rates of individual stars; on order of 10�??5M yr�??1 . Hence, we estimate the total mass entering the interstellar medium to be 1.06 �? 10�??4M yr�??1 and 2.89 �? 10�??4M yr�??1 for NGC 147 and NGC 185.

Download TeX format
back to top
scroll left or right