Gaia 17bpi: An FU Ori Type Outburst

Abstract

We report on the source Gaia 17bpi and identify it as a new, ongoing FU Ori type outburst, associated with a young stellar object. The optical lightcurve from Gaia exhibited a 3.5 mag rise with the source appearing to plateau in mid/late 2018. Mid-infrared observations from NEOWISE also show a $>$3 mag rise that occurred in two stages, with the second one coincident with the optical brightening, and the first one preceding the optical brightening by $\sim$1.5 years. We model the outburst as having started between October and December of 2014. This wavelength-dependent aspect of young star accretion-driven outbursts has never been documented before. Both the mid-infrared and the optical colors of the object become bluer as the outburst proceeds. Optical spectroscopic characteristics in the outburst phase include: a GK-type absorption spectrum, strong wind/outflow in e.g. Mgb, NaD, H$\alpha$, KI, OI, and CaII profiles, and detection of LiI 6707 Å. The infrared spectrum in the outburst phase is similar to that of an M-type spectrum, notably exhibiting prominent $H_{2}O$ and ${}^{12}$CO (2-0) bandhead absorption in the K-band, and likely HeI wind in the Y-band. The new FU Ori source Gaia 17bpi is associated with a little-studied dark cloud in the galactic plane, located at a distance of 1.27 kpc.

Accepted to ApJ

References in corpus (7)

• Initial Performance of the NEOWISE Reactivation Mission
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• The relation between gas and dust in the Taurus Molecular Cloud
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Cited by in corpus (30)

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• Diagnosing FUor-like Sources: The Parameter Space of Viscously Heated Disks in the Optical and Near-IR
• Short and long term near-infrared spectroscopic variability of eruptive protostars from VVV
• Analysis of physical processes in eruptive YSOs with near infrared spectra and multi-wavelength light curves
• Application of a Steady-State Accretion Disk Model to Spectrophotometry and High-Resolution Spectra of Two Recent FU Ori Outbursts
• Discovery of a mid-infrared protostellar outburst of exceptional amplitude
• PTF 14jg: The Remarkable Outburst and Post-Burst Evolution of a Previously Anonymous Galactic Star
• Dissecting the different components of the modest accretion bursts of the very young protostar HOPS 373
• Gaia 20eae: A newly discovered episodically accreting young star
• Recurrent strong outbursts of an EXor-like young eruptive star Gaia20eae
• Accretion Burst Echoes as Probes of Protostellar Environments and Episodic Mass Assembly
• Spectroscopic confirmation of high-amplitude eruptive YSOs and dipping giants from the VVV survey
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• Migrating Planets into Ultra-Short-Period Orbits during Episodic Accretion Events
• Gaia21bty: An EXor lightcurve exhibiting an FUor spectrum
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• Multi-wavelength detection of an ongoing FUOr-type outburst on a low-mass YSO
• Rapidly evolving Galactic plane outbursts in NEOWISE: Revisiting the Galactic nova rate with the first all-sky search in the mid-infrared
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• Global magnetohydrodynamic simulations of the inner regions of protoplanetary discs. I. Zero-net flux regime
• Photometric and spectroscopic study of the burst-like brightening of two Gaia-alerted young stellar objects
• Spectroscopy of 9 eruptive young variables using TANSPEC
• The Effelsberg survey of FU Orionis and EX Lupi objects I. -- Host environments of FUors/EXors traced by NH${}_3$
• Characterizing and spectrally modeling embedded FUor eruptions in the near-infrared