ANU Open Research Repository has been upgraded. We are still working on a few minor issues, which may result in short outages throughout the day. Please get in touch with if you experience any issues.

Isolated Star Formation: A Compact H II Region in the Virgo Cluster




Gerhard, Ortwin
Arnaboldi, Magda
Freeman, Kenneth
Okamura, Satoshi

Journal Title

Journal ISSN

Volume Title


IOP Publishing


We report on the discovery of an isolated compact H II region in the Virgo cluster. The object is located in the diffuse outer halo of NGC 4388 or possibly could be in intracluster space. Star formation can thus take place far outside the main star-forming regions of galaxies. This object is powered by a small starburst with an estimated mass of ∼400 M⊙ and age of ∼3 Myr, From a total sample of 17 H II region candidates, the present rate of isolated star formation estimated in our Virgo field is small, ∼10-6 M⊙ arcmin-2 yr-1. However, this mode of star formation might have been more important at higher redshifts and might be responsible for a fraction of the observed intracluster stars and total cluster metal production. This object is relevant also for distance determinations with the planetary nebula luminosity function from emission-line surveys, for high-velocity clouds and the in situ origin of B stars in the Galactic halo, and for local enrichment of the intracluster gas by Type II supernovae.



Keywords: Galaxies: abundances; Galaxies: ISM; Galaxies: star clusters; H II regions; Intergalactic medium; Stars: formation



Astrophysical Journal, The


Journal article

Book Title

Entity type

Access Statement

License Rights



Restricted until