A Thought On White Dwarfs and Habitable Planets

[Dryson]

Aye sire. I'm working on it....
Finding another habitable Earth like planet.
I think the search pattern for a habitable planet should begin with suns that are close to Earth, maybe within 100 LY, that would be able to receive the elements from a sun such as hydrogen, oxygen and carbon. One search pattern would begin with all of the White Dwarfs within 100 LY of Earth.Their patterns of orbit would be rewound in time to see how close they came to the Earth. If any of the White Dwarfs came close to Earth or to our Sun there could have been a transfer of mass from our Sun to the White Dwarf that did not cause an explosion but allowed venting of the White Dwarf to release its carbon, oxygen and hydrogen rich atmosphere unto the Earth.
A crystallized core of the White Dwarf passing close to our sun could have possibly have shattered sending the hydrogen,oxygen and carbon crystals to a nearby rocky planet to seed the planet with life.
The Oort Cloud that surrounds our solar system is comprised of hydrogen and oxygen which is obvious because of the large number of icy comets.
Perhaps a White Dwarf accompanied our Sun in it's past and when the core of the White Dwarf started to crystallize, sublimation of the White Dwarf took place that cause pieces of the White Dwarf to break free of the White Dwarf that then impacted the Earth leaving behind water, hydrogen and trace amounts of carbon that evolve into life.
The White Dwarf Shards that did not impact the Earth then raced spacewards collecting dust until they settled into orbit around our Sun.
How else would so much ice chunk mass be in the Oort Cloud unless a White Dwarf with comparable mass had been present in our Soloar System at one time.
"Ready for Transport."
"Yes, Doctor."
"Energize."
"Feels tingly, wouldn't you say Doctor?"
"For once could you keep your funhole SHUT during a transport?"
"Doctor, I seriously doubt that your predilection of...."
"Oh for the love of...."

 

[PurpleBuddha]

Who only has one funhole?

 

[sojourner]

A crystallized core of the White Dwarf

LOL.

 

[Asbo Zaprudder]

A crystallized core of the White Dwarf ...

LOL.

Hmm, hold on. That much is believed to be correct.

https://www.newscientist.com/article/dn4692-moon-sized-crystal-revealed-in-stars-heart/
http://abyss.uoregon.edu/~js/ast122/lectures/lec17.html

...passing close to our sun could have possibly have shattered sending the hydrogen,oxygen and carbon crystals to a nearby rocky planet to seed the planet with life.

Not sure how you shatter a white dwarf that typically has a mass somewhere around 0.8 solar masses (1.4 is the upper Chandrasekhar Limit) and where the surface gravity is around 10^5 times that of the Earth (10^6 m/s/s compared with 9.81 m/s/s). There is a lower mass limit as red dwarf stars live too long. At the low mass end, white dwarfs probably don't have sufficient mass or the correct composition to crystallise anyway.

White dwarfs lower than 0.5 solar masses should not be present because of their long progenitor lifetimes. [The] plot shows there are some, forming a separate small bump. These weirdos have formed through binary interactions that can hasten the demise of a star. Lower mass white dwarfs are made of helium, rather than the carbon/oxygen mixture typical of most white dwarfs.

http://physics.stackexchange.com/qu...-dwarf-mass-distribution-highly-peaked/249909

https://imagine.gsfc.nasa.gov/science/objects/dwarfs2.html

 

[Dryson]

Who only has one funhole?

...Oh for the love of...

 

[PurpleBuddha]

Its okay, you can yell out that last word.

 

[Asbo Zaprudder]

What's the safeword?

 

[psCargile]

Sounds like anime from the 80s.

 

[Asbo Zaprudder]

I preferred his folk period.

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[lpetrich]

0

Finding another habitable Earth like planet.

Our best bet for that is more telescopes.

One search pattern would begin with all of the White Dwarfs within 100 LY of Earth.Their patterns of orbit would be rewound in time to see how close they came to the Earth. If any of the White Dwarfs came close to Earth or to our Sun there could have been a transfer of mass from our Sun to the White Dwarf that did not cause an explosion but allowed venting of the White Dwarf to release its carbon, oxygen and hydrogen rich atmosphere unto the Earth.

It would have to get VERY close by interstellar standards, and that is VERY improbable. It's not difficult to come up with a very hand-waving sort of estimate of how improbable:
(time before close encounter) ~ 1/( (number density of stars) * (close-encounter cross section) * (average velocity) )
where (close-encounter cross section) = pi* (close-encounter distance)^2.

For another star getting as close to the Sun as the Earth, it would take about 10^(15) years. It would also have to make that eruption when that close.

A crystallized core of the White Dwarf passing close to our sun could have possibly have shattered sending the hydrogen,oxygen and carbon crystals to a nearby rocky planet to seed the planet with life.

Except that it's under very high pressures by Solar-System standards, and it would quickly vaporize when the pressure is removed.

There is also the problem of departing from the WD. The Sun's escape velocity is about 618 km/s, and white dwarf stars are much more compressed. Here are two nearby white dwarfs in binary systems, something that can give us good mass values:

• Sirius B: 0.978 Msun, 0.0084 Rsun, 0.056 Lsun, 25200 K, <225-250 Myr -- 6700 km/s
• Procyon B: 0.602 Msun, 0.01234 Rsun, 0.00049 Lsun, 7740 K, 1.37 Gyr -- 4300 km/s

Source: Wikipedia. Some theoretical calculations: [astro-ph/9909499] Mass-radius relations for white dwarf stars of different internal compositions I've also found CO White Dwarf Cooling (theoretical calculations of cooling times).

So the most that one can get from a WD is something like a stellar flare.

 

[lpetrich]

As to planets of white dwarfs, they would either be leftovers from when the WD's were "normal" stars, or somehow formed from material left behind as its progenitor star blew off much of its mass. But then again, we've found neutron-star planets.

I've found these numbers for white-dwarf cooling, from a paper I'd mentioned in my previous post in this thread. They are (billions of years, log10 of luminosity in Sun units)

• 0.54 Msun ... 0.5, -2.7 ... 1.0, -3.2 ... 2.0, -3.6 ... 5.0, -4.1 ... 10.0, -4.6
• 0.77 Msun ... 0.5, -2.4 ... 1.0, -2.8 ... 2.0, -3.4 ... 5.0, -3.8 ... 10.0, -4.5
• 1.00 Msun ... 0.5, -2.1 ... 1.0, -2.6 ... 2.0, -3.0 ... 5.0, -3.6 ... 10.0, -4.6

So if a planet of a WD had an Earthlike temperature about 5 billion years after the WD formed, it had a Mercurylike temperature only 1 billion years after.

A planet with an Earthlike temperature and a WD age of 5 billion years would have to orbit very close in.

• 0.54 Msun ... 0.016 AU ... 1.0 d
• 0.77 Msun ... 0.020 AU ... 1.2 d
• 1.00 Msun ... 0.032 AU ... 2.1 d

 

[publiusr]

Here is a star in a tight orbit around a black hole
http://www.centauri-dreams.org/?p=37345

There's a good gravity assist.