Notes on These New Variables

This list is more narrowly focused than the one in "Mining Hipparcos’s Buried Treasure," for all of these stars are tentatively classed in ESA's Hipparcos and Tycho Catalogues as eclipsing binaries — close, unresolved pairs in which one star circles another in an orbit nearly edge on to our view. Probably neither component varies by itself, but their combined brightness drops each time one passes in front of the other and blocks some or all of its light.

A few stars on this list may stay constant for months or years before exhibiting any telltale dip. The mere fact that no one noticed their variations in the past tells us so. The Hipparcos mission, which lasted from late 1989 through mid-1993, made only 30 to 380 measurements of any given star — not enough, in most cases, to produce a reliable light curve or establish the period unambiguously.

Because their minima can't be predicted with certainty, the best approach is to get to know these stars and check up on them every clear night. Be prepared to keep this up for many months to come. You might become the first person to nail down a star's period so that more detailed studies of its behavior can begin.