Gaia 18dvy: A New FUor in the Cygnus OB3 Association
E. Szegedi-Elek, P. Ábrahám, Ł. Wyrzykowski, M. Kun, Á. Kóspál, L. Chen, G. Marton, A. Moór, C. Kiss, A. Pál, L. Szabados, J. Varga, E. Varga-Verebélyi, C. Andreas, E. Bachelet, R. Bischoff, A. Bódi, E. Breedt, U. Burgaz, T. Butterley, J. M. Carrasco, V. Čepas, G. Damljanovic, I. Gezer, V. Godunova, M. Gromadzki, A. Gurgul, L. Hardy, F. Hildebrandt, S. Hoffmann, M. Hundertmark, N. Ihanec, R. Janulis, Cs. Kalup, Z. Kaczmarek, R. Könyves-Tóth, M. Krezinger, K. Kruszyńska, S. Littlefair, M. Maskoliūnas, L. Mészáros, P. Mikołajczyk, M. Mugrauer, H. Netzel, A. Ordasi, E. Pakštienė, K. A. Rybicki, K. Sárneczky, B. Seli, A. Simon, K. Šiškauskaitė, Á. Sódor, K. V. Sokolovsky, W. Stenglein, R. Street, R. Szakáts, L. Tomasella, Y. Tsapras, K. Vida, J. Zdanavičius, M. Zieliński, P. Zieliński, O. Ziółkowska
Abstract
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.