I figure we will be asked about the planet discovery that was in the paper so here are the stats:

Star Name: Gliese 581 – also listed as variable star HO Lib
Spect: M3V
Mass: .031 Suns
Luminosity: .013 Suns
Apparent Mag: 10.55
Surface Temp: 3500 K
Distance: 20 ly or 6 pc
Variability: BY Dra type (variability is due to the star’s rotation carrying sunspots into and out of view). I didn’t see anything on it being a flare star but it wouldn’t surprise me.

Planetary System: Has at least 6 planets-the one in the paper being Gliese581G. Three of the planets straddle the “Liquid Water Zone” with one on the inner edge, one on the outer edge and Gliese581G smack in the middle (hence the moniker “Goldilocks”). The newest planet has a mass of 3-4 times the earth with surface gravity about 1.2 times the Earth’s. It orbits about 0.146 AU from the primary with a year of approx 36 days. Obviously at this distance it is probably tidally locked.

I have also made up two AAVSO charts-the 15 deg “a” and the 3 deg. “b” scale. The 2.6 mag star on the “a” chart is Beta Lib. The title
lists the star under its variable star designation HO Lib. The pattern of stars just south of the target star on the “b” chart is located just northeast of Beta Lib on the “a” chart.. The “b” chart magnitude limit is 11.0

Article by Dave Majors

2010-09-30T22:25:27+00:00