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Date: Mon, 15 Nov 1993 23:27:28 +0000 (WET) From: Fred Ringwald <far@astro.keele.ac.uk> Subject: PG2300+166 (was: VS observations) Dear Dr. Kato: On Tue, 16 Nov 1993, Taichi Kato wrote: > PG2300+166 931112.540 124 Myy What do you know about PG2300+166? Has it ever shown any variability? My spectrum of it shows it not to be a cataclysmic variable, in contradiction to Green et al. (1982, PASP, 94, 560). Instead, it has a subdwarf-B spectrum. Still, it may have a cool companion, which together with the hot subdwarf could mimic the flat spectrum of a cataclysmic variable, causing Green et al. to misclassify it. I found many such stars in my thesis: about half the objects listed as cataclysmic variables by the Palomar-Green catalog (Green, Schmidt, & Liebert 1986, ApJS, 61, 305) are in fact not cataclysmic variables. Donald Ferguson found many stars in the Palomar-Green Survey like this, too (Ferguson, Green, & Liebert 1984, ApJ, 297, 320). In other words, PG2300+166 may be a detached binary that is the progenitor of a cataclysmic variable (a "precataclysmic binary"), or at least related to them (see Ritter, 1986, A&A, 169 139). If so, it would be one of the brightest such stars in the Palomar-Green catalog. Also, the hot star may heat the cool star significantly, and give rise to an illumination variation, which is generally, though wrongly, called a "reflection effect". Such a variation would be smooth and sinusoidal in shape, of 0.1 -- 1.0 magnitudes in amplitude, with a period of several hours to several days. Do you see any evidence for such a variation? =========================================================================== Fred Ringwald ... to further the progress of science, Department of Physics to guide to an understanding Keele University, Keele of the majesty of the hea
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