by Ann » Sat May 28, 2016 7:46 pm
APOD Robot wrote:
Planetary nebulae have long been appreciated as a final phase in the life of a sun-like star.
These sun-like stars may not always be so sun-like.
The graph at left of the temperature-magnitude diagram of globular cluster M3 suggests that this cluster still contains stars of the same spectral class as the Sun, even though M3 and its constituent stars are much older than the Sun. How old is M3? Opinions vary, but according to
this paper M3 (also known as NGC 5272) is 11.39 billion years old. If that is correct, then the sun-like stars of M3 have survived for 11.39 billion years without even turning into red giants, much less into white dwarfs and planetary nebulas.
In other words, is there a single planetary nebula in the Milky Way that is the remnant of a once a truly sun-like star? Is there a single planetary nebula in the Local Group of galaxies that is the remnant of a star born with the mass of the Sun? Maybe not. Maybe at least 95% of all 1.0 solar mass hydrogen fusing stars ever born in the universe still survive?
Perhaps (almost) all planetary nebulas in the Local Group are remnants of stars that were born with more mass than the Sun. Perhaps the typical planetary nebulas that the universe has seen so far emanate from stars born as F-type main sequence stars, 1½ times as massive as the Sun, like
Gamma Virginis, Porrima.
Ann
[quote]APOD Robot wrote:
Planetary nebulae have long been appreciated as a final phase in the life of a sun-like star.[/quote]
These sun-like stars may not always be so sun-like.
[float=left][img2]http://casswww.ucsd.edu/archive/physics/ph5/images/hr_gc.gif[/img2][c][size=85]Temperature-Magnitude diagram for globular cluster M3.[/size]
[size=75]Source: http://casswww.ucsd.edu/archive/physics/ph5/StevII.html[/size][/c][/float] The graph at left of the temperature-magnitude diagram of globular cluster M3 suggests that this cluster still contains stars of the same spectral class as the Sun, even though M3 and its constituent stars are much older than the Sun. How old is M3? Opinions vary, but according to [url=https://arxiv.org/pdf/1001.4289v1.pdf]this paper[/url] M3 (also known as NGC 5272) is 11.39 billion years old. If that is correct, then the sun-like stars of M3 have survived for 11.39 billion years without even turning into red giants, much less into white dwarfs and planetary nebulas.
In other words, is there a single planetary nebula in the Milky Way that is the remnant of a once a truly sun-like star? Is there a single planetary nebula in the Local Group of galaxies that is the remnant of a star born with the mass of the Sun? Maybe not. Maybe at least 95% of all 1.0 solar mass hydrogen fusing stars ever born in the universe still survive?
Perhaps (almost) all planetary nebulas in the Local Group are remnants of stars that were born with more mass than the Sun. Perhaps the typical planetary nebulas that the universe has seen so far emanate from stars born as F-type main sequence stars, 1½ times as massive as the Sun, like [url=http://astronomer.wpengine.netdna-cdn.com/wp-content/uploads/2012/05/porrrima.jpg]Gamma Virginis, Porrima[/url].
Ann