[vsnet-chat 5117] Re: Interesting star GSC 6870 1665

[Brian Skiff <Brian.Skiff@lowell.edu>]

     The Tycho-2 magnitude is for one component of a moderately close,
nearly equal pair.  The star is HD 172258.  The Tycho-2 VT magnitudes
for each component are 9.17 and 9.34.  Since the correction for stars
near B-V = 0 is small, we can ignore the adjustment to the standard system.
Simply summing the brightness of the two stars yields 8.50.  Since the
stars are close the Tycho photometry could be in error, and I note that
classical catalogues (CPD, CoD) show much brighter magnitude estimates.
I suspect this explains the anomalous brightness of the star.

\Brian

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