HS 0822+3542 - A new nearby extremely metal-poor galaxy

A. Y. Kniazcv*, S. A. Pustilnik, J. Masegosa, I. Márquez, A. V. Ugryumov, J. M. Martin, Y. I. Izotov, D. Engels, N. Brosch, U. Hopp, S. Merlino, V. A. Lipovetsky

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We present the results of spectrophotometry and BV R CCD photometry, as well as integrated HI radio measurements of a new blue compact galaxy (BCG) HS 0822+3542 with extremely low oxygen abundance: 12+log(O/H) = 7.35, or 1/36 of solar value. The galaxy is the third most metal-deficient BCG after I Zw 18 and SBS 0335-052. Its very high mass fraction of gas (≈ 95% of all visible mass) and blue colours of underlying nebulosity are also similar to those of SBS 0335-052. This suggests that HS 0822+3542 is one of the nearest and dimmest galaxies experiencing a recently-started first star formation (SF) episode. Its properties imply that for such galaxies there is a linear scaling of the main parameters, at least for the baryon mass range (0.3-20)×108 M. The total mass estimate indicates that the galaxy is dynamically dominated by a dark matter (DM) halo, which itself is one of the least massive for galaxies.

Original languageEnglish
Pages (from-to)101-110
Number of pages10
JournalAstronomy and Astrophysics
Issue number1
StatePublished - 2000


  • Galaxies: abundances
  • Galaxies: fundamental parameters
  • Galaxies: individual: Hs 0822+3542
  • Galaxies: photometry
  • Galaxies: star-burst


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