Habitable zone around white dwarfs?

Question:

Is it possible to have a planet form, perhaps from the accretion disk
of a binary star, that would be at a location close enough in to a
white dwarf that it would get an illumination from the residual
radiation of the white dwarf that would be the equivalent of the
amount of radiation that falls on the earth from the sun, or would
that theoretical orbit be far within the Roche limit for a white dwarf?

In article .com,
Orbitan wrote:

Question:

Is it possible to have a planet form, perhaps from the accretion disk
of a binary star, that would be at a location close enough in to a
white dwarf that it would get an illumination from the residual
radiation of the white dwarf that would be the equivalent of the
amount of radiation that falls on the earth from the sun, or would
that theoretical orbit be far within the Roche limit for a white dwarf?


Not likely.

If both stars formed together, then the process of forming a white dwarf would
not be conducive to survival of planets.

--
COOSN-174-07-82116: Official Science Team mascot and alt.astronomy's favourite
poster (from a survey taken of the saucerhead high command).

Official maintainer of the supra-cosmic space fluid pump (Mon and Tues only).

"Orbitan" wrote in message
oups.com...
: Question:
:
: Is it possible to have a planet form, perhaps from the accretion disk
: of a binary star, that would be at a location close enough in to a
: white dwarf that it would get an illumination from the residual
: radiation of the white dwarf that would be the equivalent of the
: amount of radiation that falls on the earth from the sun, or would
: that theoretical orbit be far within the Roche limit for a white dwarf?
:

Ask Captain Kirk.

On 3 Juni, 10:33, "Androcles" wrote:
"Orbitan" wrote in message

oups.com...
: Question:
:
: Is it possible to have a planet form, perhaps from the accretion disk
: of a binary star, that would be at a location close enough in to a
: white dwarf that it would get an illumination from the residual
: radiation of the white dwarf that would be the equivalent of the
: amount of radiation that falls on the earth from the sun, or would
: that theoretical orbit be far within the Roche limit for a white dwarf?
:

Ask Captain Kirk.

Actually i think that both Captain Picard and Data is better suited to
answer this question of Orbitan, you can also look for a study made by
Scotty cheif engineer at Enterprise named "When white midgets in
costume turn into clowns".

For more recent data on the subject i personally would refer to
captain JaneWay's essay "An intergalactic threesome with a giant and a
white unicorn", it is a somewhat quantum mechanic approach to the wiew
of matter "pun intendedd".
It is packaged in a joyful brickstone thick novel that surely will
give you hours of joyful reading.

XYZ

wrote in message
ups.com...
: On 3 Juni, 10:33, "Androcles" wrote:
: "Orbitan" wrote in message
:
: oups.com...
: : Question:
: :
: : Is it possible to have a planet form, perhaps from the accretion disk
: : of a binary star, that would be at a location close enough in to a
: : white dwarf that it would get an illumination from the residual
: : radiation of the white dwarf that would be the equivalent of the
: : amount of radiation that falls on the earth from the sun, or would
: : that theoretical orbit be far within the Roche limit for a white
dwarf?
: :
:
: Ask Captain Kirk.
:
: Actually i think

Liar.

On Jun 3, 2:53 am, "Androcles" wrote:
wrote in message

ups.com...
: On 3 Juni, 10:33, "Androcles" wrote:
: "Orbitan" wrote in message
:
: roups.com...
: : Question:
: :
: : Is it possible to have a planet form, perhaps from the accretion disk
: : of a binary star, that would be at a location close enough in to a
: : white dwarf that it would get an illumination from the residual
: : radiation of the white dwarf that would be the equivalent of the
: : amount of radiation that falls on the earth from the sun, or would
: : that theoretical orbit be far within the Roche limit for a white
dwarf?
: :
:
: Ask Captain Kirk.
:
: Actually i think

Liar.

This is a post to sci.physics,
and sci.astro, two crank-infested
usenet groups in theory dedicated
to actual reality and not science
fiction.

I suggest that you read Lucian's
preface to 'A True Story'. Unless
you can come up with verifiable
and testable emperical physical
evidence for an actual true existant
time-traveling or space-traveling
Captain Kirk, and not a false and
fictitious one.

On Jun 2, 5:40 pm, Phineas T Puddleduck
wrote:
In article .com,

Orbitan wrote:
Question:

Is it possible to have a planet form, perhaps from the accretion disk
of a binary star, that would be at a location close enough in to a
white dwarf that it would get an illumination from the residual
radiation of the white dwarf that would be the equivalent of the
amount of radiation that falls on the earth from the sun, or would
that theoretical orbit be far within the Roche limit for a white dwarf?

Not likely.

If both stars formed together, then the process of forming a white dwarf would
not be conducive to survival of planets.

True, during the initial formation of both stars.

This scenario would involve the first star going
off the main sequence and becoming a white
dwarf. Then the second star would do the same
and dump matter into an accretion disk around
the first white dwarf. It would ultimately not
dump enough matter to make the first go
supernova before it also became a white dwarf.

The accretion disk left behind might then in
theory condense into a planet. At least if
tidal forces even allowed it at all. Which would
bring one back to the initial question.




--
COOSN-174-07-82116: Official Science Team mascot and alt.astronomy's favourite
poster (from a survey taken of the saucerhead high command).

Official maintainer of the supra-cosmic space fluid pump (Mon and Tues only).

"Orbitan" wrote in message
oups.com...
: On Jun 3, 2:53 am, "Androcles" wrote:
: wrote in message
:
: ups.com...
: : On 3 Juni, 10:33, "Androcles" wrote:
: : "Orbitan" wrote in message
: :
: : roups.com...
: : : Question:
: : :
: : : Is it possible to have a planet form, perhaps from the accretion
disk
: : : of a binary star, that would be at a location close enough in to a
: : : white dwarf that it would get an illumination from the residual
: : : radiation of the white dwarf that would be the equivalent of the
: : : amount of radiation that falls on the earth from the sun, or would
: : : that theoretical orbit be far within the Roche limit for a white
: dwarf?
: : :
: :
: : Ask Captain Kirk.
: :
: : Actually i think
:
: Liar.
:
: This is a post to sci.physics,
: and sci.astro, two crank-infested
: usenet groups

Then you fit right in.

In article .com,
Orbitan wrote:

Not likely.

If both stars formed together, then the process of forming a white dwarf
would
not be conducive to survival of planets.

True, during the initial formation of both stars.

This scenario would involve the first star going
off the main sequence and becoming a white
dwarf. Then the second star would do the same
and dump matter into an accretion disk around
the first white dwarf. It would ultimately not
dump enough matter to make the first go
supernova before it also became a white dwarf.

The accretion disk left behind might then in
theory condense into a planet. At least if
tidal forces even allowed it at all. Which would
bring one back to the initial question.


The material left in the accretion disc would still accrete onto the WD even if
not being fed because the feeder star is no longer supplying matter. Just
because it isn't being replenished doesn't stop the process of accretion and so
the remaining disc would spiral into the WD leaving a pretty empty binary WD
system. Plus the process of accretion forms what is commonly called
microquasars so the energetics of the system are pretty dead against planetary
formation.



--
COOSN-174-07-82116: Official Science Team mascot and alt.astronomy's favourite
poster (from a survey taken of the saucerhead high command).

Official maintainer of the supra-cosmic space fluid pump (Mon and Tues only).

"Phineas T Puddleduck" wrote in message
news
The material left in the accretion disc would still accrete onto the WD
even if
not being fed because the feeder star is no longer supplying matter. Just
because it isn't being replenished doesn't stop the process of accretion
and so
the remaining disc would spiral into the WD leaving a pretty empty binary
WD
system. Plus the process of accretion forms what is commonly called
microquasars so the energetics of the system are pretty dead against
planetary
formation.

I'm not so sure that one can emphatically rule out the
possibility that such an accretion disk could not form
an orbiting body. Much would depend upon where in their
life cycles the two stars are. With a two star system
it is also possible to imagine capture scenarios.

It might be worthwhile, for the sake of argument, to simply
suppose that such planets could exist and move on to
addressing the actual question. That is, where is the
habitable zone around a white dwarf and does at least some
of it lie outside the Roche limit.