Wfraumann wrote:For a rank amateur, it would be interesting if they were able to take away all the extraneous stars that are not part of the Nebula itself so I could get a better idea of what stars are actually part of the nursery. Is that possible?
To me it looks like all the stars seen within the boundary of the bright nebula are genuine members of clusters born in it. All the stars "inside" the nebula are about the same color, and they are of moderately the same brightness. Check out this
Hubble image of NGC 602. All the stars but one is blue, and the yellow star is just "outside" the nebula. This might be a foreground star, but to me it seems just as likely that it is a star born out of NGC 602 which has already evolved into a red giant. Also, since the position of NGC 602 is relatively "isolated" in the wing of SMC, we may assume that there are not all that many bright foreground of background SMC stars located along our line of sight to this bright nebula. Nevertheless, there are really some yellow and not remarkably bright stars just outside the nebula which may be unrelated to the nebula and not born inside it.
On a different note, it is interesting to consider how many foreground Milky Way stars we are seeing in this picture. Once
Gaia has done its job, provided everything works out like it is supposed to, we will indeed be able to say with certainty which stars in this APOD really belong to the SMC and which are foreground Milky Way stars. But for now, we have no such certainty.
However, there are a few things we
can say. Take a look at the bright yellow star at about 1 o'clock. Is that a foreground star? Yes, definitely. The bright yellow star is HD 9210, and it is of the 9th magnitude, while the brightest star in the SMC,
HD 5980, is of the 11th magnitude when seen from the Earth. No star apparently located in the Small Magellanic Cloud can be of the 9th magnitude when seen from the Earth unless it is either a foreground star or a supernova (or at least some sort of bright nova). And no supernova or bright nova has been reported in the SMC since I started taking a serious interest in astronomy in the 1970s, so therefore the bright yellow star at about 1 o'clock in this picture is a foreground star.
But there are a few other rather bright orange stars in this picture, which might indeed be genuine red supergiants in the SMC.
Ann
[quote="Wfraumann"]For a rank amateur, it would be interesting if they were able to take away all the extraneous stars that are not part of the Nebula itself so I could get a better idea of what stars are actually part of the nursery. Is that possible?[/quote]
To me it looks like all the stars seen within the boundary of the bright nebula are genuine members of clusters born in it. All the stars "inside" the nebula are about the same color, and they are of moderately the same brightness. Check out this [url=http://upload.wikimedia.org/wikipedia/commons/thumb/8/81/NGC602.jpg/800px-NGC602.jpg]Hubble image of NGC 602[/url]. All the stars but one is blue, and the yellow star is just "outside" the nebula. This might be a foreground star, but to me it seems just as likely that it is a star born out of NGC 602 which has already evolved into a red giant. Also, since the position of NGC 602 is relatively "isolated" in the wing of SMC, we may assume that there are not all that many bright foreground of background SMC stars located along our line of sight to this bright nebula. Nevertheless, there are really some yellow and not remarkably bright stars just outside the nebula which may be unrelated to the nebula and not born inside it.
On a different note, it is interesting to consider how many foreground Milky Way stars we are seeing in this picture. Once [url=http://sci.esa.int/gaia/]Gaia[/url] has done its job, provided everything works out like it is supposed to, we will indeed be able to say with certainty which stars in this APOD really belong to the SMC and which are foreground Milky Way stars. But for now, we have no such certainty.
However, there are a few things we [i]can[/i] say. Take a look at the bright yellow star at about 1 o'clock. Is that a foreground star? Yes, definitely. The bright yellow star is HD 9210, and it is of the 9th magnitude, while the brightest star in the SMC, [url=http://en.wikipedia.org/wiki/HD_5980]HD 5980[/url], is of the 11th magnitude when seen from the Earth. No star apparently located in the Small Magellanic Cloud can be of the 9th magnitude when seen from the Earth unless it is either a foreground star or a supernova (or at least some sort of bright nova). And no supernova or bright nova has been reported in the SMC since I started taking a serious interest in astronomy in the 1970s, so therefore the bright yellow star at about 1 o'clock in this picture is a foreground star.
But there are a few other rather bright orange stars in this picture, which might indeed be genuine red supergiants in the SMC.
Ann