Habitable planets for Lalande 21185 and Sirius A

[jude_rook]

Here are life zone and planetary year calculations for a couple of nearby stars, one much smaller and cooler than Sol, one much larger and hotter.

Lalande 21185: Here is a link to some basic data on this red dwarf star.  As it seems to have a luminosity of only 0.025 (two and a half percent of Sol’s), its life zone is a lot closer and narrower, ranging from 0.11 AU on the inside to 0.24 on the outside.  Earth twin distance comes out to 0.16.  An Earth twin’s “year” would be around 23 days long.

Sirius A: Basic data on this spectral class A star can be found here.  Its luminosity is a whopping 22.61, which puts its life zone’s boundaries at 3.33 and 7.13 AU.  Earth twin distance is 4.75 AU.  An Earth twin’s year would be 10.37 Earth years long – that’s 3785 days!  Remember, though, that Sirius is a young star, and a planet at Earth twin distance wouldn’t have had a chance to become all that Earthlike.