Gaia 18dvy: A New FUor in the Cygnus OB3 Association
Gromadzki, M.; Szabados, L.; Mugrauer, M.; Pál, A.; Ábrahám, P.; Chen, L.; Varga, J.; Kóspál, Á.; Breedt, E.; Carrasco, J. M.; Kruszyńska, K.; Kun, M.; Marton, G.; Rybicki, K. A.; Szegedi-Elek, E.; Wyrzykowski, Ł.; Damljanovic, G.; Ihanec, N.; Moór, A.; Kiss, C.; Sárneczky, K.; Bachelet, E.; Zieliński, P.; Gezer, I.; Tsapras, Y.; Hundertmark, M.; Krezinger, M.; Sódor, Á.; Tomasella, L.; Mikołajczyk, P.; Netzel, H.; Simon, A.; Littlefair, S.; Bódi, A.; Könyves-Tóth, R.; Ordasi, A.; Szakáts, R.; Vida, K.; Sokolovsky, K. V.; Seli, B.; Street, R.; Ziółkowska, O.; Varga-Verebélyi, E.; Pakštienė, E.; Godunova, V.; Maskoliūnas, M.; Kaczmarek, Z.; Zdanavičius, J.; Čepas, V.; Janulis, R.; Šiškauskaitė, K.; Burgaz, U.; Butterley, T.; Andreas, C.; Bischoff, R.; Gurgul, A.; Hardy, L.; Hildebrandt, F.; Hoffmann, S.; Kalup, Cs.; Mészáros, L.; Stenglein, W.; Zieliński, M.
Hungary, Poland, Germany, Netherlands, United States, United Kingdom, Japan, Turkey, Spain, Lithuania, Serbia, Ukraine, Russia, Italy
Abstract
We present optical-infrared photometric and spectroscopic observations of Gaia 18dvy, located in the Cygnus OB3 association at a distance of 1.88 kpc. Gaia 18dvy was noted by the Gaia alerts system when its light curve exhibited a ≳4 mag rise in 2018-2019. The brightening was also observable at mid-infared wavelengths. The infrared colors of Gaia 18dvy became bluer as the outburst progressed. Its optical and near-infrared spectroscopic characteristics in the outburst phase are consistent with those of bona fide FU Orionis-type young eruptive stars. The progenitor of the outburst is probably a low-mass K-type star with an optical extinction of ∼3 mag. A radiative transfer modeling of the circumstellar structure, based on the quiescent spectral energy distribution, indicates a disk with a mass of 4 × 10-3 M⊙. Our simple accretion disk modeling implies that the accretion rate had been exponentially increasing for more than 3 yr until mid-2019, when it reached a peak value of 6.9 × 10-6 M⊙ yr-1. In many respects, Gaia 18dvy is similar to the FU Ori-type object HBC 722.