Number of sun like stars in galaxy?

"Jonathan Silverlight" wrote in message ...
In message , Rick
writes
"aquablue" wrote in message
...

You'd have to define what's meant by "sun-like star". The number of
F, G, K main sequence non-multiple-system stars that are between .75
and 1.25 solar masses is probably something like two percent of the
stars in the galaxy. So roughly a billion, give or take. It's much
more likely to be 10^9 than 10^10 or 10^8, anyway.

A multiple-star system does not preclude the existence of
Earth-like planets, it just makes the existence of Earth-like
planets a little less probable (and we're not even sure about
that much!). Some believe our own sun is part of a
multiple-star system with Alpha Centauri.

How so? It's four light years away. On that basis _every_ star is part
of a multiple star system, because they are about that far apart.

From what I've read, some astronomers believe our sun
and the Alpha Centauri system revolve around each other.
That would make our sun part of a multiple star system,
technically if not practically.

Rick

aquablue wrote:

pity--so few... that sucks for chances of life


Well, multiply that by 100 billion...the approximate number
of galaxies and the prospects improve...

Paul

"aquablue" wrote in message ...
pity--so few... that sucks for chances of life

Two billion in this galaxy alone is "so few"? You would have felt
better if the number were more like ten billion than two? Why? A
billion is a lot.

The fact that there are a whole lot of stars *not* like the sun does
not diminish the chance of life around stars that *are* like the sun.
I get the feeling you'd think the chance of life was higher if the
galaxy contained 1 billion stars, all of them similar to the Sun, than
if it contained 100 billion stars, 2 billion of which are similar to
the Sun -- but the latter case contains twice as many candidate stars
as the former.

Think about it. 10^9 is a *really* *big* *number*.

There's no particular reason why life can only exist around Sun-like
stars, anyway. Maybe we're aberrent -- maybe most life is on close-in
planets of red dwarfs.

Besides, the chance of life is 1.0. Or did you mean chance of life in
more than one place?

But you do need to adjust your thinking. The fact that there's a
whole lot of stars that aren't like the sun doesn't mean there are "so
few" stars that are like the sun. There are a whole hell of a lot of
stars.


"eyelessgame" wrote in message
om...
"aquablue" wrote in message
...
How many sun like stars are in this galaxy -- on average?

Thx
alan

I assume you mean "at a guess".

The galaxy has roughly a hundred billion stars. (All these numbers
could be off by a factor of 2 or so. Take with a grain of salt.)

You'd have to define what's meant by "sun-like star". The number of
F, G, K main sequence non-multiple-system stars that are between .75
and 1.25 solar masses is probably something like two percent of the
stars in the galaxy. So roughly a billion, give or take. It's much
more likely to be 10^9 than 10^10 or 10^8, anyway.

eyelessgame

"eyelessgame" wrote in message
om...
"aquablue" wrote in message
...
How many sun like stars are in this galaxy -- on average?

I assume you mean "at a guess".

The galaxy has roughly a hundred billion stars. (All these numbers
could be off by a factor of 2 or so. Take with a grain of salt.)

In Serge Brunier's "The Great Atlas of the Stars" he says, "Astronomers
estimate that the Milky contains more than a thousand billion stars." So we
may be off by a factor of 10 or so.