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
California Institute of Technology · Flatiron Institute · Harvard University · California Institute of Technology · California Institute of Technology · California Institute of Technology
astro-ph.SR
Submitted: 2026-06-18
Comments: submitted to ApJ Letters
License: http://creativecommons.org/licenses/by/4.0/
The gist: 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.
Terminology
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.
Sources
- A Parameterized YSO Accretion Disk Model with Increasing Accretion Rate: Predicted Outburst Lightcurves
- Accretion Variability as a Guide to Stellar Mass Assembly
- Quantitative Spectroscopic Diagnostics for FU Orionis-Type Young Stellar Objects
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