The Nacreous Oughts

02 February 2012

GJ 667Cc, with a minimum mass of 4.5 earth's & a revolution period of 28.15 days, is the latest "Earth-analogue" to be announced (2/2/12). A second planet in the system (#6 on this list, after Vinegaroon, i have not yet considered it for naming. (For now i am going with "Manât".) The system being metal-poor (log Fe/H= -0.59), i would expect it to be rather large.

HR 6426, HIP 84709 ABC has a Hipparchos parallax of ".14345 & stellar magnitudes of 5.91, 7.98, & 10.24 respectively. Its age is estimated at 2-10 billion years. Component C is now at an apparent distance of 30" (8-30.5") from the A-B system, which corresponds to 230 AU at 6.8 parsecs. The spectral type of C is given as M1.5 or M2.5 & its mass 0.310 times the Sun's.

The visual luminosity at this distance is 0.003393117467 which is not a bad fit for M2 V (though the mass then should be higher, up to 0.4) & using a B.C. -1.58 & stellar temperature 3310 K i derive a bolometric luminosity of 0.014541154 & a stellar radius of 0.37. The blackbody temperature of the exoplanet comes to 277.4072271 K.

If these observed separations for the AB-C system represents its limits, the eccentricity is 0.58 & the semimajor axis is around 134 AU (total mass 1.564), for a period of 1243 years.

The planet orbits at 0.122567211 AU. Its tidal effect works out to 20.6, so a synchronous rotation is to be expected. In other words, this world will be much like the now-disputed Zarmina...

This star continues to surprise us.(6/13)

--According to a somewhat arbitrary algorithm of my own, the metallicity 0.257039578 corresponds to a planetary density of 0.36 times Earth's; this makes the radius 2.318662321, gravity 0.837023217 & escape velocity 1.39309322. (7/14)


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