The star formation history of the LSB galaxy UGC 5889

¹ Astronomical Observatory of Padova, Vicolo dell' Osservatorio 5, 35122 Padua, Italy
² European Southern Observatory, Casilla 19001, Santiago 19, Chile
³ Astronomisches Institut der Ruhruniversität Bochum, 44780 Bochum, Germany e-mail: vallenari@astrpd.pd.astro.it

Received: 21 April 2004
Accepted: 24 January 2005

Abstract

We present HST photometry of the LSB galaxy UGC 889 and derive its recent star formation history. In the last 200 Myr the star formation proceeded in modest bursts at a rate of the order of 10^-2–10^-3 /yr, with periods of extremely low SFR or even quiescence. The rate derived from the present study for the last 20 Myr is in agreement with the H_α emission from the galaxy. The presence of a consistent population older than 200 Myr is suggested by the data. However, observational errors and completeness correction prevent any firm conclusion on the oldest age. The total mass of stars is of the order of 5.5  . Even if the recent episodes of star formation have heated the gas and carved a hole in the disk, blow-away of the gas is unlikely to occur.