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Space Forum / Astronomy / March 2007White dwarves
What would Procyon B and Sirius B look like for nearby observers? The masses are well-known (about 0,98 solar masses for Sirius B, 0,6 solar masses for Procyon B), the sizes are also pretty exactly known (Sirius B is the smaller, just slightly smaller than Earth). Both orbit main sequence stars on eccentric orbits of similar size. Both receive less light from A component than Earth from Sun, even at closest approach. Sirius B is about 120 millions of years old, and has temperature of 25 000 Celsius. Procyon B is older (under 1700 million years, but how much less?) and colder (at 7700 Celsius, just slightly hotter than Sun). Can anyone give more numbers about rotation rates and magnetic field strengths of Sirius B and Procyon B? What would an old white dwarf look like, assuming age of the white dwarf between 4 and 10 milliards of years? Any guesses as to temperature, rotation rate, magnetic field? Shut up, innumerate cretin: http://groups.google.com/group/rec.arts.sf.science/msg/6f2737cfb5610220. > Shut up, innumerate Illiterate? No, the troll actually meant innumerate, although IMHO the OP doesn't classify. Maybe the troll read this book: http://en.wikipedia.org/wiki/Innumeracy_%28book%29 and had a beer or two. I remember my first beer. == John == >> Shut up, innumerate > > Illiterate? > I remember my first beer. When I was seventeen, I had a very good beer, I had a very good beer, that I bought, with a fake ID, The name was Brian McGee, I stayed up listening to Queen, When I was seventeen. Paul > Any guesses as to > temperature, rotation rate, magnetic field? It depends on origial star. You can calculate it from loss of angular momentum. Raghar kirjutas: > > Any guesses as to > > temperature, rotation rate, magnetic field? > > It depends on origial star. We were not around to observe original Sirius B, Procyon B or Keid B. > You can calculate it from loss of angular > momentum. But you cannot predict the said loss even if you do observe an original star. > Can anyone give more numbers about rotation rates and magnetic field > strengths of Sirius B and Procyon B? I doubt these are known, but you could try an ADS search or look for references in SIMBAD. > What would an old white dwarf look like, assuming age of the white > dwarf between 4 and 10 milliards of years? Any guesses as to > temperature, rotation rate, magnetic field? Temperature gradually decreases with time. Try an ADS search on "white dwarf cooling curve." Rotation rates and magnetic fields will be harder to find out, though some white dwarfs (note preferred plural) are highly magnetized. |
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