How big can a star be?

Answer 1

The largest star is probably about 150-200 times the mass of the Sun. There are probably only a handful of these hyperstars in our own Milky Way which has over 200 billion stars in it.

Answer 2

I don't know the answer, but I think I might know the .
(This is from memory, from an astronomy course I once took.)

Several decades ago, astronomers (Harlow Shapely, I think) were working on the relations between a star's mass, its luminosity, and its distance. Using "standard candles" such as RR-Lyrae & Cepheid variable stars, they got the distance- luminosity relationship worked out, and then they could relate mass vs. luminosity.

The result of this was the "K-S Diagram" -- a line with a negative slope using a logarithmic x-axis -- flanked or bounded by a hysteresis curve above and below. This diagram links mass and luminosity with time; it shows the life cycle of stars. Our sun -- a somewhat larger than average star -- is on the "main sequence", is about 5 billion years old, and can be expected to last another 5 billion or so years, going through a "red giant" stage before collapsing into a brown dwarf.

The negative slope of the K-S diagram implies that there's an inverse relationship between a star's mass and its life expectancy; larger stars burn their fuel much faster, and therefore have shorter lives.

That, in turn, implies some sort of size limit on stars. How large would a star be, if its life expectancy is only two seconds? Obviously, such a star, if formed at all, would be highly unstable.

Working backward in terms of life expectancy, a mass the size of Jupiter never "ignites" the nuclear process that makes it a star, so it never consumes its own fuel. It could last forever.

Next, small stars burn their fuel very slowly and can last a very long time before burning out quietly.

Our sun will remain stable on the main sequence for a long time, then become a red giant, blow off the outer layers, and settle down as a brown dwarf. Betelgeuse is a red giant now.

Larger stars such as Aldebaron and Antares will have much shorter lives, burning their fuel furiously, then collapsing precipitously before exploding as a supernova, then possibly ending up as a quasar.

This may be the size limit -- 150 or 200 solar masses mentioned by other posters.

Still larger incipient stars may be too massive to sustain a stable life as a star at all. As the gas clouds of these behemoths converge, the gravity may be such that they collapse into a black hole; they're too massive to become stars.

So that's what I have to say.

Answer 3

The biggest star is the Pistol Stars and its about 200 solar masses

Answer 4

Shelley Winters was pretty big. She had trouble getting through that tub, Poseidon.


Ohhnh, not that kind of star.

Answer 5

A star can be very big. There are small ones, and big ones.
***http://www.du.edu/~jcalvert/astro/starsiz.htm***

***http://www.enchantedlearning.com/subjects/astronomy/stars/startypes.shtml***

***http://www.st-v-sw.net/STSWdeathstarsizes.html

There are a couple websites. ; )