Hubble - greatest discoveries
The lives of stars:
How Hubble has revolutionised our understanding of the birth and death of stars
Most of the light and radiation we can observe in the Universe originates in stars – individual stars, clusters of stars, nebulae lit by stars and galaxies composed of billions of stars. Like human beings stars are born, mature and eventually die. Hubble has gone beyond what can be achieved by other observatories by linking together studies of the births, lives and deaths of individual stars with theories of stellar evolution (see also heic0707 and heic0703).
In particular Hubble's ability to probe stars in other galaxies enables scientists to investigate the influence of different environments on the lives of stars. This is crucial in order to be able to complement our understanding of the Milky Way galaxy with that of other galaxies.
Uncovering the Galaxy's stellar nurseries
Hubble's work allowed it to link star formation with stellar evolution. Its infrared instruments are capable of looking through the dust clouds surrounding newly born stars. Some of the most surprising discoveries so far have come about by peering through the clouds of dust surrounding the centre of our Milky Way. Astronomers found that this centre, which was thought to be a calm and almost dead region, is in fact populated with massive infant stars gathered into clusters.
The last phases of solar-like stars have been investigated through observations of planetary nebulae and proto-planetary nebulae. These are colourful shells of gas expelled into space by dying stars. The varying shapes and colours of these intricate structures with different colours tracing different, often newly created, chemical elements, have shown that the final stages of the lives of stars are more complex than once thought and there also seems to exist a bizarre alignment of planetary nebulae.
Gamma Ray Bursts
Gamma Ray Bursts emit very intense gamma-ray radiation for short periods and are observed a few times per day by special gamma-ray detectors on observatories in space. Today, partly due to Hubble, we know that these bursts originate in other galaxies – often at very large distances.
Their origin has eluded scientists for a long time, but, after Hubble observations of the atypical supernova SN1998bw and the Gamma Ray Burst GRB 980425 a physical connection of these became probable.
An unusual burst of radiation detected in early 2011 may tell a different story: rather than a star ending its life in a supernova, this burst may be evidence of a star being ripped apart as it falls into a supermassive black hole. If confirmed by further observations, this would be the first time this phenomenon has ever been spotted.
This is one of nine articles highlighting some of the greatest discoveries made by the Hubble Space Telescope. Read more in the articles linked from the right-hand menu.