Two Earth-Sized Bodies With Oxygen-Rich Atmospheres 111
tugfoigel writes "Astrophysicists at the University of Warwick and Kiel University have discovered two bodies the size of earth with oxygen-rich atmospheres — however, there is a disappointing snag for anyone looking for a potential home for alien life, or even a future home for ourselves. These are not planets, but are actually two unusual white dwarf stars." The objects, 220 and 400 light-years distant, are believed to be remnants of stars between 7 and 10 solar masses. Such stars, the largest that evolve to white dwarves, have been sought for years. If the stars were a little more massive they would collapse to neutron stars, or so the theory goes. Here is the paper on the arXiv.
Re:bummer... (Score:4, Informative)
Cough, Cough... (Score:1, Informative)
Ever heard of the Smoke Ring??
Cough, cough.
Man...
white dwarfs not white dwarves (Score:3, Informative)
Re:Earth sized stars? (Score:3, Informative)
Do you mean bigger? White dwarfs are all fairly close to the earth in size. They are still far more massive, however A white dwarf probably retains 70-80% of the mass of the original star... 5-7 solar masses in this case. These are apparently near the border area, not quite massive enough to crush the space out of their atoms and become a neutron star. A neutron star is way smaller... with a radius of 10km or less.
Re:Deceptive headlines (Score:3, Informative)
Pish, putting a spin on things is old news. If you own a NIV Bible, congrats, you already own a book where theologians twist the source material to censor embarrassing verses.
Take Songs 5:4 for example:
It's like taking "You idiot, you aren't wearing a condom!" and publishing it as "Dear, your pen is uncapped." on the virtue that "pen is" remotely looks like "penis" which, when substituted, gives a meaning similar to the original.
Re:Earth sized stars? (Score:1, Informative)
The upper limit on a white dwarf's mass is the Chandrasekhar limit (roughly 1.4 solar masses); The paper posits that the two dwarfs in question have masses of .9-1.2 solar masses.
Re:That's okay. (Score:3, Informative)
All known arrangements of life either consume oxygen or produce it, either way we will find free oxygen anywhere we find such life.
All known arrangements of life depend on liquid water, even in those under-glacier lakes or deep ocean thermal vents, liquid water is necessary. Therefore we will find liquid water anywhere we find such life.
Unless there is some arrangement for life than is fundamentally different from ours, on a molecular level, then oxygen and liquid water will be found anywhere life will be found.
Re:Deceptive headlines (Score:4, Informative)
the estimated masses are around one solar mass, which means they are no where near earth-sized
From the Wiki article [wikipedia.org]: "[White dwarfs] are very dense; a white dwarf's mass is comparable to that of the Sun and its volume is comparable to that of the Earth."
Be very careful about calling other people stupid when you're about to say something demonstrably false.
Re:Earth sized stars? (Score:1, Informative)
Reading the paper you can see these white dwarfs are a lot less massive than that. About 1 solar mass.
Chandrasekhar limit says the electron degeneracy pressure can only hold up a white dwarf of up to about 1.4 solar masses, anything bigger becomes a neutron star. At the range you're talking about (5-7 solar masses) you're probably looking at black holes.
White dwarfs are a lot heavier than earth, but due to their immense gravity they compress themselves into a size not much larger than a terrestrial planet. Interestingly, the more massive white dwarves can be smaller. There is a relation that holds over a reasonable range of masses in that mass multiplied by volume will be a constant.
Re:white dwarfs not white dwarves (Score:3, Informative)
Schwarzschild radius (Score:5, Informative)
Not quite so small, as the Schwarzschild radius [wikipedia.org] of the sun is about 3 km.
Actually, it's believed that type 1A supernovae do not reach gravitational collapse [wikipedia.org], they explode in a runaway carbon fusion before reaching the Chandrasekar limit. It's type II supernovae [wikipedia.org] that explode the way you mention.
Re:Deceptive headlines (Score:3, Informative)
Try an osteopath - they've really studied their subject and are practically specialist doctors. Chiropractors are masseurs that like to take risks.