Chee Lan's home planet, Lifehome-under-Sky/Cynthia, is O2 Eridani A II. I think that "Eridani A II" would mean "the second planet of the brightest star in the constellation, Eridanus" but I do not know what the "O2" means. (That is meant to be a small 2 to the lower right of the O.)
Googling "Eridanus," I learned that:
there is an Eridanus supervoid;
filaments of gravitationally bound galaxies are the largest known structures in the universe and form the boundaries of voids.
I did not know any of that.
Poul Anderson speculated about trans-galactic cosmic structures in Tau Zero and World Without Stars. See here. But he did not know about filaments or voids.
3 comments:
Kaor, Paul!
And the Eridanus cluster of stars lies 144 light years from Sol, which means it would have fallen within the sphere of space claimed by Terra after the Empire arose. And the Cynthians were very willing to join the Empire!
Sean
From Wikipedia
"40 Eridani is the system's Flamsteed designation and ο² Eridani (Latinised to Omicron2 Eridani) its Bayer designation. The designations of the sub-components – 40 Eridani A, B and C – derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU)"
So the A indicates it is the brightest star in a multiple star system. The 40 or the o2 indicate it is the 40th star in the Eridanus constellation. Usually that means 40th brightest, but astronomers haven't been totally consistent about ordering by brightness within a constellation.
The II would be an osbolete way of designating which planet orbiting a star it is. Since planets orbiting stars other than the sun started being found, the first found is b 2nd c etc. The star itself would be 'a', but I have never seen that written out.
BTW Sean: A web search finds an Eridanus cluster of Galaxies 75 million light years away, but I don't find an Eridanus star cluster. Not sure why we got different results from searches.
Kaor, Jim!
Very interesting, many thanks! Another system I've sometimes seen being used, including some of the stories of Anderson is this: a star is named X, the planet closest to that star is I, the second is II, and so on. So our home star is Sol, its nearest planet (Mercury) is I, Venus is II, Earth is III, Mars is IV, and so on to Pluto, IX. I refuse to accept Pluto's demotion to being a mere "dwarf planet"!
Some groupings of stars might be called "clusters" simply for convenience, not because they are actually clusters, technically.
Ad astra! Sean
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