Gaia 18dvy: a new FUor in the Cygnus OB3 association

• Main Authors: Szegedi-Elek, E, Ábrahám, P, Wyrzykowski, L, Kun, M, Kóspál, A, Chen, L, Marton, G, Moór, A, Kiss, Cs, Pál, A, Szabados, L, Varga, J, Varga-Verebélyi, E, Andreas, C, Bachelet, E, Bischoff, R, Bódi, A, Breedt, E, Burgaz, U, Butterley, T, Čepas, V, Damljanovic, G, Gezer, I, Godunova, V, Gromadzki, M, Gurgul, A, Hardy, L, Hildebrandt, F, Hoffmann, S, Hundertmark, M, Ihanec, N, Janulis, R, Kalup, Cs, Kaczmarek, Z, Könyves-Tóth, R, Krezinger, M, Kruszyńska, K, Littlefair, S, Maskoliūnas, M, Mészáros, L, Mikołajczyk, P, Mugrauer, M, Netzel, H, Ordasi, A, Pakštienė, E, Rybicki, K. A, Sárneczky, K, Seli, B, Simon, A, Šiškauskaitė, K, Sódor, Á, Sokolovsky, K. V, Stenglein, W, Street, R, Szakáts, R, Tomasella, L, Tsapras, Y, Vida, K, Zdanavičius, J, Zieliński, M, Zieliński, P, Ziółkowska, O
• Format: Journal Article
• Language: English
• Published: 16-06-2020
• Subjects: Physics - Solar and Stellar Astrophysics
• DOI: 10.48550/arxiv.2005.11537

We present optical-infrared photometric and spectroscopic observations of
Gaia18dvy, located in the Cygnus OB3 association at a distance of 1.88 kpc. The
object was noted by the Gaia alerts system when its lightcurve exhibited a
$\gtrsim$4 mag rise in 2018-2019. The brightening was also observable at
mid-infared wavelengths. The infrared colors of Gaia18dvy 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 $\sim$3 mag. A radiative
transfer modeling of the circumstellar structure, based on the quiescent
spectral energy distribution, indicates a disk with a mass of
$4{\times}10^{-3}\,M_{\odot}$. Our simple accretion disk modeling implies that
the accretion rate had been exponentially increasing for more than 3 years
until mid-2019, when it reached a peak value of $6.9 \times
10^{-6}\,M_{\odot}$yr$^{-1}$. In many respects, Gaia18dvy is similar to the FU
Ori-type object HBC 722