The unusual photometric variability of the PMS star GM Cep

Abstract

Results from UBVRI photometric observations of the pre-main sequence star GM Cep obtained in the period April 2011 - August 2014 are reported in the paper. Presented data are a continuation of our photometric monitoring of the star started in 2008. GM Cep is located in the field of the young open cluster Trumpler 37 and over the past years it has been an object of intense photometric and spectral studies. The star shows a strong photometric variability interpreted as a possible outburst from EXor type in previous studies. Our photometric data for a period of over six years show a large amplitude variability (Delta V ~ 2.3 mag.) and several deep minimums in brightness are observed. The analysis of the collected multicolor photometric data shows the typical of UX Ori variables a color reversal during the minimums in brightness. The observed decreases in brightness have a different shape, and evidences of periodicity are not detected. At the same time, high amplitude rapid variations in brightness typical for the classical T Tauri stars also present on the light curve of GM Cep. The spectrum of GM Cep shows the typical of classical T Tauri stars wide H/alpha emission line and absorption lines of some metals. We calculate the outer radius of the H/alpha emitting region as 10.4 +/-0.5 Rsun and the accretion rate as 1.8 x 10 E-7 Msun/yr.

arXiv comment9 pages, 4 figures, accepted for publication in PASA. arXiv admin note: text overlap with arXiv:1111.2166

References in corpus (7)

• Explaining UXOR variability with self-shadowed disks
• Highly Variable Extinction and Accretion in the Jet-driving Class I Type Young Star PTF 10nvg (V2492 Cyg, IRAS 20496+4354)
• Disk-Related Bursts and Fades in Young Stars
• V1647 Orionis: Reinvigorated Accretion and the Re-Appearance of McNeil's Nebula
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• Diagnosing the Clumpy Protoplanetary Disk of the UXor Type Young Star GM Cephei
• V2492 Cygni: Optical BVRI variability during the period 2010-2017
• Study of the long-term $BV{R}_c{I}_c$ photometric variability of eight PMS stars in the young open cluster Trumpler 37
• Long-term Photometric Study of the Pre-main Sequence Star V1180 Cas