AAVSO: American Association of Variable Star Observers

The Reclassification of NSV 1586 from a Suspected Cepheid Star to a UG Class System

Volume 48 number 1 (2020)

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Stephen M. Brincat
Flarestar Observatory (MPC 171), Fl.5/B, George Tayar Street, San Gwann SGN 3160, Malta; stephenbrincat@gmail.com
Charles Galdies
Znith Observatory, Armonie, E. Bradford Street, Naxxar. NXR 2217, Malta; charles.galdies@um.edu.mt
Kevin Hills
Tacande Observatory, El Paso, La Palma, Spain; kevinhills@me.com
Winston Grech
Antares Observatory, 76/3 Kent Street, Fgura FGR 1555, Malta; wingrech@gmail.com

Abstract

On 2018 August 9, a contribution to the VSNET mailing list suggested that due to certain photometric attributes, NSV 1586 could possibly belong to the Dwarf Nova (DN) class. Hence, the initial classification of this star as a Cepheid variable star was put into question. This prompted the authors to investigate NSV 1586 in detail. The data obtained through our campaign suggest that the original classification of NSV 1586 as a Cepheid star is inconsistent with our findings. We determined the nature of NSV 1586 as a UG-type DN that exhibits peculiar photometric features in its light curve to possibly pertain to the UGZ/IW sub-type variable star classification. However, standstills that are indicative of this class remained undetected. The amplitude of this star was found to be of 2.9 magnitudes in the V-band, with a primary cycle period of 13.9 days. We found the color index during its cyclic permutations can range from an apparent CI of 0.5 to 1.0, corresponding to a temperature change of around 1300 K. Further research is suggested to determine the nature of this star.