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Re: Star to star relationships
From: Peter Monta
Date: 2016 Sep 27, 11:21 -0700
From: Peter Monta
Date: 2016 Sep 27, 11:21 -0700
Frank Reed writes:
Don't forget Arcturus! :)
Or, to give the star its currently-accepted IAU name, "herbertprinz". The astrology literature is being updated accordingly.
Mark Coady writes:
I forgot all about that expanding/contracting universe theory stuff about stars moving with respect to each other
I was about to write that I don't think the Hubble flow has a direct impact on reference frames; but then again, what about our small motion with respect to the CMB frame (dipole)? Should the aberration resulting from that be included willy-nilly in the ICRS? It's a bit parochial that ICRS should include it; instead the ICRS definition should be with respect to the CMB frame, and users should compute the correction for situations like the Solar System barycenter frame or other frames.
Another star-position modifier is gravity (deflection of starlight), but it is very small, way too small to be of interest to sextant users. Missions like Gaia must take it into account, though, certainly for the Sun and the large planets.
Cheers,
Peter
