SF-06-0010

Evolution of the vertical thermal profile of an inner disc in an episodic accretion event

Joe Philip Ninan, Suvrath Mahadevan, HPF Team

In this poster, we present our observations which indicate how the vertical thermal profile of the inner accretion disc of V899 Mon evolved around a short duration episodic high accretion event. V899 Mon is a young protoplanetary disc system currently undergoing a long FUors/EXor type episodic accretion event. In 2018, in the middle of its ongoing outburst phase, it underwent a flare-up. Our multi-epoch, high-resolution, near-infrared spectra of this source obtained using the Habitable Zone Planet Finder (HPF) spectrograph show evolution in the low gravity Y band lines from weak to strong absorption, and then to emission. All of this transition happened during the period of flare up and in the subsequent years of slow decay to the quiescent phase accretion. Since low gravity lines in these sources are believed to form in the hot inner accretion disc, we model this as evolution in the vertical thermal profile of the inner disc.