C/2084 N1

21 07 2011

Eleven months after Planetfall, a bright, magnificent comet appeared between Scorpius and Ophiuchus.

Its discoverer named it not after herself but for the middle name of a grandmother left long behind on Earth. Ironically, Comet Tsumugi was discovered as a dirty smudge through a telescope only days before its nucleus began a period of intense outgassing and was visible to all, even during daylight.

It had three visible tails that stretched across forty degrees of the sky, and as it made its closest approach to Fram, it brightened up to magnitude negative eight. The two bluish tails were of ionized gases, and pointed in two directions away from Alpha A and Alpha B. There was a broader, curved tail of dust, and in this dust tail, spiral structures appeared. Tsumugi was laid like a striated carpet across the southern hemisphere of Fram’s sky.

The astronomers explained that it was a fresh comet, as unseen by Fram as it was by those who had so recently come to live upon her surface. Its first journey into the inner system from the Oort Cloud brought it whipping around Alpha B in an elliptical orbit that was deeply declined to the plane of the ecliptic. Its perihelion was a bare thirty-five million kilometres from the star; its closest approach to Fram was a hundred and twenty million kilometres.

Tsumugi’s surface was a dark, primordial crust of frozen carbon dioxide, methane, ammonia and heavy long-chain organics that protected its core of water ice. The light of two main sequence stars warmed the crust, and it absorbed this warmth, its darkness reflecting barely four percent of the light it received. Outgassing began when exposed water ice began to sublimate.

After it passed perihelion, Comet Tsumugi was visible even during those hours of daylight when both suns were in the sky. It was a commanding, inspiring sight, a vision of the beauty of the Universe, made all the more special by the bitterly cold and immense gulf between Fram and Home.

The astronomers also explained that, back Home, great comets were visible from Earth on average once a decade. They said that great comets would be much more frequent in the Alpha Centauri system – with its dense scattered disc and dispersed Oort Cloud, filled with the material that had composed the gas giants around Sol, and disturbed by the interactions of three stars. We would see many more great comets.

But never again Tsumugi. Gravitational perturbations caused by the two stars sent Comet Tsumugi slinging out into an orbital period of millions of years. The comet looped around Alpha B and sailed gracefully back out to the deep scattered disc, to be lost forever in the night…




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