(pic by Lanny Quarles on Facebook)

Wolf 1061 (=prime), AKA Gliese 628, Vyssotsky 164, HIP 80824, & BD-12° 4523 (oldstyle)(4523 is also prime), in Ophiuchus, has been discovered (as of 12/15) to have 3 terrestrial-type planets in close-in orbits. Located at a distance of 14.0 light years, this is presently the closest prospect for an earthlike exoplanet. (It goes between #5 & #6 on this list.)

Parallax is given as 0."23451 (Hipparcos) or 0."23298 (I use); apparent magnitude 10.1 (I use Hipparcos’s 10.0278), which gives a visual luminosity of 0.001607607232 ⊙. The spectral type is variously given as M3-3.5 V & M4. It is listed on Simbad as a BY Dra variable (=V2306 Oph)--this is also the source of the other parallax. I find that using M2.5, with T= 3280K (3393 is given) & BC= -1.71, giving a total luminosity of 0.007765688238, is closest to the 0.00787 which is given. This star appears to be somewhat hotter & less massive than usual for its brightness.)

The planets have periods of 4.8876, 17.867, & 67.274 days. If the star’s mass is 0.25 (I would give it at least 0.30--if the star's mass is higher, a planet's average temperature for the same orbital period would be colder), then the middle planet’s semimajor axis comes to 0.084258922 (= 1/12) AU. (Note that its eccentricity is considerable: 0.19.) Its resultant blackbody temperature is 286.0K. Not a lot higher than Earth’s 279K, but the average temperature for synchronous rotation is more like 40% higher, with temperatures around the globe varying according to both the distance from the subsolar point, & the orientation of local winds (which are bound to be considerable). Apparent size of this red sun would be 3.27 ⊙. The blackbody at periastron 0.068249726 AU is 317.8K & at apastron 0.100268117 it is 262.2, so it varies ± 27.8K.

All in all, an almost perfect equivalent to the (probably mythical) "ribbon-world" Zarmina. (Although i am now seeing the term "eyeball earth" more often.)

Synodic periods of b & d relative to c would be 6.73 & 24.33 days, respectively. If the radius is 1.64 ⊕, surface gravity would be 1.58 ⊕ if 1.60 (by another formula), it would be more like 1.9⊕. With such gravity, i would expect not bipeds but tripeds or quadrupeds as the dominant species... The star does not appear in fiction, except for the video game Traveller, where a planet is named "Apishal" (in the same game, Ross 47 is Remulak--home planet of the Coneheads). I like the names Audelia, Claymore, Antobia here...

Labels: #exoplanets