Number of sun like stars in galaxy?

How many sun like stars are in this galaxy -- on average?

Thx
alan

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

Since we only have one galaxy, I'm not sure what you mean by "on average,"
but I'm going to venture a hypothesis here that in any event we really don't
know. Heck, you can't even get a straight number from the experts for the
number of stars (of any sort) in our galaxy. I suspect a lot of this has to
do with the fact that we can't see most of our galaxy (i.e., everything at
the galactic core and beyond) due to the obscuring dust clouds.

the reason I ask is: marcy says that she estimates that 12% of sun like
stars would have a similar solar system arangement to ours -- thus may have
capacity for earth like planets harboring life.


"Kilolani" wrote in message
ink.net...
"aquablue" wrote in message
...
How many sun like stars are in this galaxy -- on average?

Since we only have one galaxy, I'm not sure what you mean by "on average,"
but I'm going to venture a hypothesis here that in any event we really
don't
know. Heck, you can't even get a straight number from the experts for the
number of stars (of any sort) in our galaxy. I suspect a lot of this has
to
do with the fact that we can't see most of our galaxy (i.e., everything at
the galactic core and beyond) due to the obscuring dust clouds.

"aquablue" wrote in message ...
the reason I ask is: marcy says that she estimates that 12% of sun like
stars would have a similar solar system arangement to ours -- thus may have
capacity for earth like planets harboring life.

That's about right, according to all the estimates I've seen
(which have ranged from 10-12%). The percentage may be
higher because large portions of the Milky Way are blocked
from our view, and because we currently have somewhat
myopic definitions of "sun-like stars" and "earth-like planets".

Rick

"aquablue" wrote in message
...
the reason I ask is: marcy says that she estimates that 12% of sun like
stars would have a similar solar system arangement to ours -- thus may
have
capacity for earth like planets harboring life.

I'm not sure how she arrived at her 12% figure. So far of the 70 or so
extrasolar planets we have found there are zero with similar solar system
arrangements to ours, and only 2 that are even close.

"Kilolani" wrote in message ink.net...
"aquablue" wrote in message
...
the reason I ask is: marcy says that she estimates that 12% of sun like
stars would have a similar solar system arangement to ours -- thus may
have
capacity for earth like planets harboring life.

I'm not sure how she arrived at her 12% figure. So far of the 70 or so
extrasolar planets we have found there are zero with similar solar system
arrangements to ours, and only 2 that are even close.

Our current detection capability sucks. We can't detect
any planets smaller than a few times' Jupiter's size.

Rick

"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.

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


"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.

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


"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.

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.

Rick

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.
--
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