ther low and others, it’s higher; this star is a field halo star, so it’s in an area of our galaxy which is not very populated, so it’s just been sitting there for many, many, many years, and because it’s a low mass star, it is still very unevolved, so it’s just waiting there for us to find it.
Fraser: What kind of star is it, because I understand that our Sun is several billion years old, but definitely not the age of the universe, so what kind of star is it that it could be as old as the Big Bang?
Frebel: The star is a low mass star, it’s a bit lighter than the Sun and that means that it evolved very very slowly. I mean the Sun, well, it’s still in its teenage years, so it hasn’t burned much. High mass stars burn very very fast, and they explode quickly as a supernova enriching the surrounding gas; the interstellar medium with heavy elements, but this star, because it is so low in mass has just been sitting there and burning its hydrogen slowly and we think the hydrogen has just finished burning. So helium should be the next stage.
Fraser: How early on do you think it actually formed? How long after the Big Bang?
Frebel: Well, we have 2 scenarios; one would be that it formed in the second generation of stars and the first generation formed within one billion years after the Big Bang. So that star should have formed very quickly, probably about one billion years after the Big Bang. And the second theory which we cannot exclude, although I personally don’t favor it, is that the star indeed is a first star itself, meaning that it formed as one of the very, very first stars in the universe and presumably that happened then within the first billion years.
Fraser: Do you think that there are many of these types of stars in the Milky Way?
Frebel: Good question; probably not because they are very old and hence they are very rare because it seems that there is a certain type of these low mass stars which are actually able to survive that long and astronomers have been searching for these types of stars for the last 30-40 years and so far, we’ve only found 2 in huge efforts, so we are really looking for the needle in the haystack I would say.
Fraser: In the last couple of years, I have been covering the fires at Mount Stromlo. How is the observatory doing?
Frebel: It’s doing very well. We haven’t been affected from a science point of view. We have been very much productive since the fires. The reconstruction has now started; we are getting an new advanced, technological instrumentation building so we have a lot of noise here, but that also means things are progressing. Everyone is doing very well and we’ve, I think psychologically, we’ve put the fires way behind us.