by Ann » Wed Jul 23, 2014 7:50 pm
Lovely picture. Totally weird caption.
http://www.eso.org/public/news/eso1422/ wrote:
Take the bright orange star at the bottom right of the cluster. This huge star, a red giant, would have been born as one of the biggest and most luminous of its litter, but bright stars burn out fast. As the star used up the fuel at its core its internal dynamics changed and it began to swell and cool, becoming the red giant we now observe. Red giants are reaching the end of their life cycle, but
this red giant’s sister stars are still in what is known as the pre-main-sequence — the period before the long, stable, middle period in a star’s life. We see these stars in the prime of their life as hot, bright and white against the red and dusty background.
There are no bright white stars in NGC 3293, but several blue ones. To me it seems impossible that the bright blue stars could be pre-main sequence stars. Guide classifies the two brightest blue stars, HD 91969 and HD 91943, as spectral classes B0Ia and B0.5Ib. Even though pre-main sequence stars are sometimes mistakenly classified as giants, I refuse to believe that a supergiant star could be mistaken for a star so young that it still hasn't got its core hydrogen fusion going.
Ann
[quote="bystander"][float=left][c][s][/s]
[url=http://www.eso.org/public/news/eso1422/][b][i]ESO: Lives and Deaths of Sibling Stars (NGC 3293)[/i][/b][/url]
[img3="Credit: ESO/G. Beccari"]http://www.eso.org/public/archives/images/screen/eso1422a.jpg[/img3][/c][/float][/quote]
Lovely picture. Totally weird caption.
[quote]http://www.eso.org/public/news/eso1422/ wrote:
Take the bright orange star at the bottom right of the cluster. This huge star, a red giant, would have been born as one of the biggest and most luminous of its litter, but bright stars burn out fast. As the star used up the fuel at its core its internal dynamics changed and it began to swell and cool, becoming the red giant we now observe. Red giants are reaching the end of their life cycle, but [b][i]this red giant’s sister stars are still in what is known as the [size=120][color=#FF40FF]pre-main-sequence[/color][/size][/i][/b] — the period before the long, stable, middle period in a star’s life. We see these stars in the prime of their life as hot, bright and white against the red and dusty background.[/quote]
There are no bright white stars in NGC 3293, but several blue ones. To me it seems impossible that the bright blue stars could be pre-main sequence stars. Guide classifies the two brightest blue stars, HD 91969 and HD 91943, as spectral classes B0Ia and B0.5Ib. Even though pre-main sequence stars are sometimes mistakenly classified as giants, I refuse to believe that a supergiant star could be mistaken for a star so young that it still hasn't got its core hydrogen fusion going.
Ann