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Tom Mazanec
2004-Nov-17, 01:00 PM
What does a star look like half way between red giant and nebula? How long does it take to go from "senile" red giant to teeny-tiny planetary nebula? Are there any such transitional objects known?

Kullat Nunu
2004-Nov-17, 01:16 PM
According to the Hubble press release (http://hubblesite.org/newscenter/newsdesk/archive/releases/1998/15/) the Stingray Nebula (Hen-1357) is the youngest known planetary nebula.


The Stingray nebula is, in human terms, just an infant because only within the past 20 years did its central star rapidly heat up enough to make the nebula start to glow. It is extraordinary to catch a star in this exceedingly brief phase of its evolution. While stars typically last for billions of years, the transition to a visible planetary nebula takes only about 100 years the blink of an eye compared to a star's lifetime. It is therefore not surprising that no younger planetary nebula has ever been identified.

Death of a low-mass star is a complex process. The star releases gas several times before settling as a white dwarf. Many planetary nebulae, for example the Ring Nebula have faint, much larger shells around the star.

Tom Mazanec
2004-Nov-17, 02:31 PM
Gee, wish the Hubble had been observing there for the last 25 years or so annually! Or that it was 18 light years instead of 18000!
Does a star have to be a binary or a certain mass or something to be a planetary? Will the sun be a planetary someday?

Hamlet
2004-Nov-17, 02:35 PM
Here (http://www-astronomy.mps.ohio-state.edu/~pogge/Lectures/vistas97.html) is a nice link that follows the evolution of the Sun from birth to death. It also gives time estimates for the various phases.

Tom Mazanec
2004-Nov-17, 02:40 PM
So the sun should look like the stingray about the year 12,365,402, 024 AD?

ToSeek
2004-Nov-17, 03:27 PM
So the sun should look like the stingray about the year 12,365,402, 024 AD?

Mark your calendar!

PhantomWolf
2004-Nov-18, 08:25 AM
So the sun should look like the stingray about the year 12,365,402, 024 AD?

Mark your calendar!

Drat, I'm going to be busy that weekend.

mickal555
2004-Nov-18, 12:19 PM
So the sun should look like the stingray about the year 12,365,402, 024 AD?

Mark your calendar!

Drat, I'm going to be busy that weekend.
Same I'll be repenting my sins... you?