Talk:Cart'hen system

I'll correct my edit comment. I read "radius", not "diameter" for some reason. Cart'hen II's a lot smaller than Pluto and Eris, is probably more comparable in size to Charon or Quaoar which are both Dwarf Planet candidates. The former is currently considered Pluto's largest moon.

The rereading also brings Cart'hen III into doubt. A diameter of 4378km puts that planet in the same ball park as Callisto (Jupiters' second largest moon) and Mercury, both have diameters in the 4800-4900km range. Density lacks a unit of measurement, but assuming it is g/cm³, that makes it more dense than any of the terrestrial planets in our solar system (all under 5.6). Surface gravity can be calculated using other stats using a formula found at List of Solar System objects by surface gravity. I've not tried checking that one myself. - Lt. Salak (Amateur Astronomer)^Talk 04:21, 4 March 2008 (CST)

Oh, and you'll be doing amazingly well to find a habitable planet around a White Dwarf. Earth like planets are only thiought possible around G type stars like our Sun, along with some F and K type stars. White Dwarfs are by definition D type. Unless I'm very much mistaken, any planets in their Goldilocks Zone would have been obliterated by the Red Giant preceeding it as its boundaries should be WITHIN the former suface of the Red Giant. Also, Cart'hen III is too small to hold on to an atmosphere, thus also too small for a runaway greenhouse effect (Venus style). Without that, to get those temps, it needs to be a LOT closer to its' star. For it to even exist, it would likely be a frozen wasteland, probably far closer in conditions to what Pluto is than to a Hot Desert. There would be no debris from the destroyed planets, they became part of the star, or the Planetary Nebula caused by the loss of its' outer shells when shrinking to a White Dwarf - Lt. Salak^Talk 05:30, 5 March 2008 (CST)

For comparison, for the White Dwarf IK Pegasi B, the average distance of the Habitable zone works out at around 0.35 AU. - Lt. Salak^Talk 05:57, 5 March 2008 (CST)