FUOr-Aur 0544+3330: A New YSO Outburst in the Outskirts of Auriga OB1, Viewed Face-On

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Hauptverfasser: Hillenbrand, Lynne A., Carvalho, Adolfo S., Stern, Dan, Connelley, Michael, Paolino, Facundo Pérez, Shetty, Ahaan, Milby, Zachariah, Isaacson, Howard
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Veröffentlicht: 2025
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author Hillenbrand, Lynne A.
Carvalho, Adolfo S.
Stern, Dan
Connelley, Michael
Paolino, Facundo Pérez
Shetty, Ahaan
Milby, Zachariah
Isaacson, Howard
author_facet Hillenbrand, Lynne A.
Carvalho, Adolfo S.
Stern, Dan
Connelley, Michael
Paolino, Facundo Pérez
Shetty, Ahaan
Milby, Zachariah
Isaacson, Howard
contents We present a newly appreciated FU Ori outburst event that began in 2019 and reached a peak in early 2021. Suspected young stellar object WISE J054452.25+333009.6 experienced substantial brightening, in excess of $-5$ mag at optical wavelengths and $-2.5$ mag at mid-infrared wavelengths. The time from near-quiescence to peak brightness was approximately 24 months. Optical and near-infrared spectra confirm that the outbursting source (hereby designated FUOr-Aur 0544+3330) shows all the hallmarks of the FU Ori class, including the Li I indicator of stellar youth. The mix of ionized and neutral atomic lines, alongside prominent molecular absorption features, is consistent with the expected change in spectral type from earlier in the optical to later-type in the near-infrared. The closest analog among well-studied FU Ori objects is V1515 Cyg. Both sources have unusually narrow-lined absorption spectra that can be explained by a face-on disk orientation, such that disk-broadening is minimized and wind-induced blueshift (in e.g. H$α$, NaD, Ca II) is maximized. Both the optical through infrared spectral energy distribution and high-resolution spectrum are well-fit by a pure-accretion disk model. Adopting a distance of $d=1.5$ kpc, the accretion and central star parameters are: $\dot{M} = 10^{-5.48}$ $M_\odot$ yr$^{-1}$, $M_* = 0.17 \ M_\odot$, and $R_\mathrm{inner} = 1.04 \ R_\odot$. Other fitted values are disk inclination $i=5.9$ deg and source extinction $A_V=1.83$ mag. These parameters yield accretion luminosity $L_\mathrm{acc} = 8.4\ L_\odot$ and maximum disk temperature $T_{\rm{max}} = 6218$ K.
format Preprint
id arxiv_https___arxiv_org_abs_2505_11440
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle FUOr-Aur 0544+3330: A New YSO Outburst in the Outskirts of Auriga OB1, Viewed Face-On
Hillenbrand, Lynne A.
Carvalho, Adolfo S.
Stern, Dan
Connelley, Michael
Paolino, Facundo Pérez
Shetty, Ahaan
Milby, Zachariah
Isaacson, Howard
Solar and Stellar Astrophysics
Earth and Planetary Astrophysics
Astrophysics of Galaxies
We present a newly appreciated FU Ori outburst event that began in 2019 and reached a peak in early 2021. Suspected young stellar object WISE J054452.25+333009.6 experienced substantial brightening, in excess of $-5$ mag at optical wavelengths and $-2.5$ mag at mid-infrared wavelengths. The time from near-quiescence to peak brightness was approximately 24 months. Optical and near-infrared spectra confirm that the outbursting source (hereby designated FUOr-Aur 0544+3330) shows all the hallmarks of the FU Ori class, including the Li I indicator of stellar youth. The mix of ionized and neutral atomic lines, alongside prominent molecular absorption features, is consistent with the expected change in spectral type from earlier in the optical to later-type in the near-infrared. The closest analog among well-studied FU Ori objects is V1515 Cyg. Both sources have unusually narrow-lined absorption spectra that can be explained by a face-on disk orientation, such that disk-broadening is minimized and wind-induced blueshift (in e.g. H$α$, NaD, Ca II) is maximized. Both the optical through infrared spectral energy distribution and high-resolution spectrum are well-fit by a pure-accretion disk model. Adopting a distance of $d=1.5$ kpc, the accretion and central star parameters are: $\dot{M} = 10^{-5.48}$ $M_\odot$ yr$^{-1}$, $M_* = 0.17 \ M_\odot$, and $R_\mathrm{inner} = 1.04 \ R_\odot$. Other fitted values are disk inclination $i=5.9$ deg and source extinction $A_V=1.83$ mag. These parameters yield accretion luminosity $L_\mathrm{acc} = 8.4\ L_\odot$ and maximum disk temperature $T_{\rm{max}} = 6218$ K.
title FUOr-Aur 0544+3330: A New YSO Outburst in the Outskirts of Auriga OB1, Viewed Face-On
topic Solar and Stellar Astrophysics
Earth and Planetary Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2505.11440