HDE 344787, the Polaris Analogue that is Even More Interesting than Polaris

摘要

A collection of active photometric observations over the last half decade,archival data from the past 120 years, radial velocity observations from 1984,and recent monitoring through a pro-am collaboration reveal that the 9thmagnitude F9 Ib supergiant HDE 344787 is a double-mode Cepheid variable ofextremely small amplitude. It displays remarkably similar, but much moreextreme, properties to the exotic Cepheid Polaris, including arapidly-increasing period and sinusoidal light variations of decreasingamplitude suggesting that pulsational stability may occur as early as 2045.Unlike Polaris, HDE 344787 displays sinusoidal light variations at periods ofboth 5.4 and 3.8 days, corresponding to canonical fundamental mode and overtonepulsation. But it may be similar to Polaris in helping to define a smallsubgroup of Cepheids that display characteristics consistent with a firstcrossing of the instability strip. An update of 2010 observations of thisremarkable star is presented.