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arXiv · 2606.20350

V7995 Sgr: A New FU Orionis Accretion Outburst Near NGC 6589/6590

Lynne A. Hillenbrand·Kishalay De·Adolfo S. Carvalho·Dan Stern·Evan Portnoi·Nicholas Earley
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Abstract

We announce a new FU Orionis type outburst that reached peak brightness in late 2024, following a steep 4.6 month photometric rise of -2.85 mag in the $r$ band. This rapid brightening at all wavelengths was preceeded in the infrared by a much shallower rise over 4 years. The progenitor object was an unstudied young stellar object having a flat-spectrum type spectral energy distribution, and extended nebulosity. We present multi-wavelength lightcurves covering the photometric low-state, the outburst, and early post-outburst epochs. Optical imaging shows a concurrent brightening of the extended nebular environment. We also present follow-up optical/near-infrared spectroscopy taken 1.5 years after the inferred photometric peak. The spectra confirm an FU Ori type outburst. The outburst source exhibits a mixed-temperature absorption spectrum, formed in an accretion disk, and it shows several line species with blueshifted absorption profiles that are formed in a strong wind.

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Lynne A. Hillenbrand, Kishalay De, Adolfo S. Carvalho, Dan Stern, Evan Portnoi, Nicholas Earley. 2026-06-18. V7995 Sgr: A New FU Orionis Accretion Outburst Near NGC 6589/6590. https://arxiv.org/abs/2606.20350

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