Tracing the history of star formation
doi:10.1038/nindia.2013.150 Published online 18 November 2013
Researchers have gained new insights into the history of star formation in the Large Magellanic Cloud (LMC), a nearby dwarf galaxy, by studying unstable, pulsating stars known as Cepheid stars in the LMC .
The LMC is one of the most studied galaxies due to its favourable viewing angle and star formation activities. Population I Cepheids have been widely used to investigate the history of star formation because they are bright, easily observable and ubiquitous in the LMC. Although many surveys of Cepheids in the LMC have been conducted, most of them were incomplete.
To obtain comprehensive data on the history of star formation in the LMC, the researchers acquired high-quality photometric data on the Cepheid stars using the Warsaw telescope at the Las Campanas Observatory in Chile.
They found that star formation in the LMC occurred on a large scale — both in terms of the total number of stars formed and in spatial extent. The enhanced frequency of stars and star clusters in the LMC are widely believed to be due to the encounters between the Small Magellanic Cloud, an irregular dwarf galaxy, and the LMC. Repeated tidal interactions between these two clouds led to episodic star-formation events in both dwarf galaxies. In addition, stellar winds and supernova explosions also induced star formation in the LMC.
The study found that major star formation occurred between 125 and 200 million years ago, probably as the result of a close encounter between the Small Magellanic Cloud and the LMC.