Deneb

Is Vega big enough to produce a supernova? I would guess it will produce
a nice quiet red giant.

In message , Mysak writes
If U mean on Earth, none.
It seem to be more than 3000 ly away (most distant of all bright stars in
sky)
Vega is much more "dangerous" in this case (only 25 ly), but still we speak
hypotetycally

Mysak


"St.George" wrote in message
...
What level of devastation will there be when Deneb explodes shortly (in
astronomical terms)?

--
"Forty millions of miles it was from us, more than forty millions of miles of
void"
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Odysseus wrote:

Nearing the end of its life at a distance of four to five hundred
light-years, Betelgeuse would seem to be much more of an imminent
threat than Vega; another red supergiant 'in the terminal ward' is
Antares, at some 500-800 LY.

Sorry, substitute "Deneb" for "Vega" above.

--
Odysseus

Odysseus wrote:

Nearing the end of its life at a distance of four to five hundred
light-years, Betelgeuse would seem to be much more of an imminent
threat than Vega; another red supergiant 'in the terminal ward' is
Antares, at some 500-800 LY.

Sorry, substitute "Deneb" for "Vega" above.

--
Odysseus

Jonathan Silverlight wrote:

Is Vega big enough to produce a supernova? I would guess it will produce
a nice quiet red giant.

According to Burnham its mass is about three times that of the sun,
well above the Chandrasekhar limit. This would seem to qualify it for
becoming a supernova after a fairly long red-giant stage, unless it
manages to eject somewhat over half its mass beforehand. But it won't
be any time soon; only the most massive supergiants are inclined to
explode at short notice, while still having substantial reserves of
unfused hydrogen.

--
Odysseus

Jonathan Silverlight wrote:

Is Vega big enough to produce a supernova? I would guess it will produce
a nice quiet red giant.

According to Burnham its mass is about three times that of the sun,
well above the Chandrasekhar limit. This would seem to qualify it for
becoming a supernova after a fairly long red-giant stage, unless it
manages to eject somewhat over half its mass beforehand. But it won't
be any time soon; only the most massive supergiants are inclined to
explode at short notice, while still having substantial reserves of
unfused hydrogen.

--
Odysseus

Odysseus wrote:


According to Burnham its mass is about three times that of the sun,
well above the Chandrasekhar limit. This would seem to qualify it for
becoming a supernova [...]

No, on second thought the C. limit is irrelevant; that's the mass at
which a white dwarf can remain stable without collapsing into a
neutron star. I now think you're right in that three solar masses
isn't quite enough to get past the helium-burning stage, so Vega will
end its life with a carbon-oxygen core. OTOH it takes a heavy-element
(up to iron) core to produce a supernova. But as a red giant I think
Vega might be expected to go through a phase of Mira-like variability
when its hydrogen is depleted, as it switches over to fusing helium
-- so perhaps not perfectly "quiet".

--
Odysseus

Odysseus wrote:


According to Burnham its mass is about three times that of the sun,
well above the Chandrasekhar limit. This would seem to qualify it for
becoming a supernova [...]

No, on second thought the C. limit is irrelevant; that's the mass at
which a white dwarf can remain stable without collapsing into a
neutron star. I now think you're right in that three solar masses
isn't quite enough to get past the helium-burning stage, so Vega will
end its life with a carbon-oxygen core. OTOH it takes a heavy-element
(up to iron) core to produce a supernova. But as a red giant I think
Vega might be expected to go through a phase of Mira-like variability
when its hydrogen is depleted, as it switches over to fusing helium
-- so perhaps not perfectly "quiet".

--
Odysseus

On Sun, 28 Sep 2003 12:30:57 +0000 (UTC), "St.George"
wrote:

What level of devastation will there be when Deneb explodes shortly (in
astronomical terms)?

It depends.

Is that going to be a Supernova or "just" a nova?

If it's a Supernova, then there won't be much left of the star, or any
potenial planets or planetoids orbiting around it.



--

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On Sun, 28 Sep 2003 12:30:57 +0000 (UTC), "St.George"
wrote:

What level of devastation will there be when Deneb explodes shortly (in
astronomical terms)?

It depends.

Is that going to be a Supernova or "just" a nova?

If it's a Supernova, then there won't be much left of the star, or any
potenial planets or planetoids orbiting around it.



--

Find out about Australia's most dangerous Doomsday Cult:
http://users.bigpond.net.au/wanglese/pebble.htm

"You can't fool me, it's turtles all the way down."

In message , Wally Angleseaâ„¢
writes
On Sun, 28 Sep 2003 12:30:57 +0000 (UTC), "St.George"
wrote:

What level of devastation will there be when Deneb explodes shortly (in
astronomical terms)?

It depends.

Is that going to be a Supernova or "just" a nova?

If it's a Supernova, then there won't be much left of the star, or any
potenial planets or planetoids orbiting around it.

Deneb is the wrong sort of star to make a nova, but it's a good
candidate for a supernova. I doubt it can have any planets of its own,
though the pulsar that will probably form may acquire planets. I
wouldn't want to be within 10 light years of it, though.
--
"Forty millions of miles it was from us, more than forty millions of miles of
void"
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