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| Paper: |
Photometric Observations of the Young Cluster Variable GM Cephei |
| Volume: |
451, 9th Pacific Rim Conference on Stellar Astrophysics |
| Page: |
345 |
| Authors: |
Hu, S. C.; Chen, W. P.; the Young Exoplanet Transit Initiative |
| Abstract: |
We present our photometric observations of GM Cep, a solar type variable in the young (∼4 Myr) open cluster
Trumpler 37. The star is known as a classical T Tauri star with a circumstellar disk and active accretion.
GM Cep was suspected to undergo an outburst, thus a candidate for an EXor-type variable. In our monitoring
campaign observations in 2010–2011, GM Cep experienced a ∼0.82 mag brightness decrease in the R band
lasting for 39 days, and frequent, transient flare-like episodes with amplitude la 1 mag, each lasting for
about 10 days. The brightening was accompanied with a bluer color, presumably arising from increased
accretion activity. Interestingly, the star also turned bluer in the fading phase.
Combining the AAVSO and literature data, we found a quasi-cyclic peroid of ∼311 days for the fading event.
A possible mechanism for the fading could be obscuration by a clump of dust around the star. We proposed
that GM Cep therefore should be a UXor-type variable in the transition phase between grain coagulation and planetesimal
formation process in the circumstellar disk. |
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