LT Dra is NOT a RCrB-Star
According to the 77th Name-List of Variable Stars (IBVS 5422, 27.05.2003))
LT Dra (=HD172468) is a new RCrB-Star, ranging from about 7.5V to fainter then 12.6V. This is not the case.
Looking on the original data from Messina et al (source: see below) one finds, that there are times, when LT Dra is in normal light, with occasional fadings below 12mag, but only within a day(!!), next day he is back to normal. At other times the star is (according to the authors) mostly invisible, but looking at the data one sees occasional brightings to normal light, but only for a day(!!).
I initialized a rather short-lived campaign for this star in the BAV (German Working Group on Variable stars) only to find within weeks, that this is a constant star, see here:
http://vsnet.bela1996.de/astronomy/hd172468.html
Peter Kroll from Sonneberg Observatory has a student there, who measured this star on more than 800 plates from the Sonneberg-collection, only to find out that there is nothing unusual (P.Kroll, private communication).
Further reading on LT Dra = HD 172468:
Messina et al: http://simbad.u-strasbg.fr/cgi-bin/cdsbib?2000A%26A...364..706M
data: http://vsnet.ct.astro.it/sme/web/apt/hd172468/mainpage.html
http://protostar.aas.org/publications/baas/v34n4/aas201/401.htm
vsnet-campaign 886
Greetings,
Béla Hassforther (German Working Group on Variable Stars, BAV)
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