New light on star birthplace
doi:10.1038/nindia.2010.96 Published online 21 July 2010
A new study has yielded interesting information about the Large Magellanic Cloud (LMC), a galaxy approximately 160,000 light years away from the Milky Way. Analysing observational data beamed back by the Far Ultraviolet Spectroscopic Explorer (FUSE) — a NASA space-based telescope — the study has shed new light on the interstellar medium (ISM), the gas and dust that pervades the space between stars.
New insights about the ISM — the birthplace of new stars — will help us better understand the process of star formation and the evolution of galaxies such as the LMC.
The ISM plays a vital role in galactic evolution through a complex feedback process. When ISM clouds collapse, stars are born; when stars die, they return their matter to the surrounding gas. The ISM is always bathed in radiation from nearby stars; it absorbs and scatters ultraviolet and optical radiation while re-emitting infrared radiation.
Observations of diffuse ultraviolet light track the transfer of radiation from the stars to the ISM. Diffuse ultraviolet radiation comprises around 5–25% of the total radiation emitted from the LMC, but until now has remained mostly unexplored. To investigate far-ultraviolet radiation in LMC, the researchers relied on the observations made by FUSE.
The researchers narrowed their search to 81 observations of diffuse radiation in different parts of the LMC, and located 30 Doradus (also known as the Tarantula Nebula) and N11 — two vigorous star-forming regions. The results showed that part of the far-ultraviolet light from hot stars is scattered by the dust grains, while the rest is absorbed and re-emitted at infrared wavelengths.
The researchers say that such an understanding of the absorption and subsequent re-emission of starlight in nearby galaxies like the LMC will provide templates for more distant galaxies.
- Pradhan, C. A. et al. Far-ultraviolet diffuse emission from the Large Magellanic Cloud. Astrophys. J. Lett. 718, L141-L144 (2010) | Article