How do we find out about the star formation histories of galaxies?
Supposing IŽd like to know how was the star formation history in a galaxy. Which stars populations or evolution stages are particulary useful to investigate this, and for which intervals of time in the past?
Different stellar populations tell astronomers different things about the history of a galaxy. This is just because different sized stars live for different lengths of time. Small stars, although they don't have very much fuel, burn it very slowly so live for billions of years. Big stars have more fuel, but burn it so much faster that they might only live for a few million years.
So if we want to learn about the recent star formation in a galaxy we can look at the big stars that are there, but to learn about star formation much longer ago we have to look at the smaller stars because the big stars from that epoch will have already died.
Other clues about the history can come from the kinematics of the stars. For example in our own galaxy the younger stars are in a thinner disk than the older stars. This is thought to be due to the collapse of the Milky Way, leaving behind in a thicker disk the older stars.
Get More 'Curious?' with Our New PODCAST:
- Podcast? Subscribe? Tell me about the Ask an Astronomer Podcast
- Subscribe to our Podcast | Listen to our current Episode
- Cool! But I can't now. Send me a quick reminder now for later.
- What is the life cycle of a star?
- Are all stars the same?
- What do a galaxy's colors mean? Are they its true colors?
- How many stars are born and die each day?
How to ask a question:
If you have a follow-up question concerning the above subject, submit it here. If you have a question about another area of astronomy, find the topic you're interested in from the archive on our site menu, or go here for help.Table 'curious.Referrers' doesn't existTable 'curious.Referrers' doesn't exist
This page has been accessed 18607 times since October 26, 2002.
Last modified: December 2, 2002 8:50:00 PM
Ask an Astronomer is hosted by the Astronomy Department at Cornell University and is produced with PHP and MySQL.
Warning: Your browser is misbehaving! This page might look ugly. (Details)