Gaia20bdk -- a new FUor in Sh 2-301 Star Forming Region

TL;DR

Gaia20bdk is a newly identified FUor star in the Sh 2-301 region, exhibiting typical eruptive features with a significant increase in luminosity and accretion rate, confirming its classification as a FUor object.

Contribution

This study provides the first detailed photometric and spectroscopic analysis of Gaia20bdk, establishing its nature as a FUor and characterizing its physical parameters during outburst.

Findings

Progenitor is a 2.7 solar mass G7-type Class I young star.

Outburst luminosity reaches 100-200 solar luminosities.

Mass accretion rate during outburst is 1-2e-5 solar masses per year.

Abstract

Context. We analyse multi-colour photometric and spectroscopic observations of a Young Stellar Object Gaia20bdk. Aims. We aim to investigate the exact nature of the eruptive phenomenon that the star has been experiencing since 2018. Methods. We use public-domain archival photometry to characterise the quiescent phase in order to establish major physical parameters of the progenitor. Then, we use our and public-domain optical and infrared photometry and spectroscopy to study the outburst. Results. Gaia20bdk is a member of the Sharpless 2-301 star-forming region, at a distance of 3.3 kpc. The progenitor is a rather massive 2.7 solar mass, G7-type Class I young star having an effective temperature of 5300 K and bolometric luminosity of 11 solar luminosities. The optical and infrared photometric and spectroscopic data obtained during the outburst show a variety of signatures commonly found in classical FUors. Our disc modelling results in a bolometric luminosity of 100-200 solar luminosities and mass accretion rate of 1-2e-5 solar masses per year, also confirming the object's FUor classification. Further monitoring is necessary to track the light changes, accretion rate and spectral variations, as well as to understood the mechanisms behind the disc flickering.