Astrochemistry

Dust And Water In V883 Ori: Relics Of A Retreating Snowline

By Keith Cowing

Status Report

astro-ph.EP

November 5, 2025

Filed under astro-ph.EP, astrochemistry, astrogeology, exoplanet, FU-Orionis-type, icy world, Spectroscopy, V883 Orionis, water snowline

Dust And Water In V883 Ori: Relics Of A Retreating Snowline — Disk temperature, vapor condensation timescale (t_cond) and number density of water (n_H₂O) during the outburst dimming phase of the best-fit model. Here t’ = t − t_beg is the time lapse since the bolometric luminosity started to decline. The value of L_bol corresponding to this time is labeled. In the top row, the range of 140-150 K is shaded in white to highlight the snowline region. At t’ = 121 yr – the present epoch – the emission surfaces (τ_mm = 2/3) of ALMA band 5, 6 and 7 and disk photosphere (see Sect. C) are plotted along with the temperature contour. In the middle row, the region where no condensation occurs is plotted in white. In the bottom row, two lines denoting ice(vapor)-to-gas ratio of 10^{−3 are indicated to highlight the snowline region. — astro-ph.EP}

V883 Ori is an FU-Orionis-type outburst system characterized by a shoulder at 50-70 au in its ALMA band 6 and 7 intensity profiles.

Previously, this feature was attributed to dust pile-up from pebble disintegration at the water snowline. However, recent multi-wavelength observations show continuity in the spectral index across the expected snowline region, disfavoring abrupt changes in grain properties.

Moreover, extended water emission is detected beyond 80 au, pointing to a snowline further out. This Letter aims to explain both features with a model in which the snowline is receding. We construct a 2D disk model that solves the cooling and subsequent vapor recondensation during the post-outburst dimming phase.

Our results show that both the intensity shoulder and the extended water emission are natural relics of a retreating snowline: the shoulder arises from excess surface density generated by vapor recondensation at the moving condensation front, while the outer water vapor reservoir persists due to the long recondensation timescales of 102−103 yr at the disk atmosphere.

As V883 Ori continues to fade, we predict that the intensity shoulder will migrate inward by an observationally significant amount of 10 au over about 25 years.

Yu Wang, Chris W. Ormel, Hao-Chang Jiang, Sebastiaan Krijt, Adrien Houge, Enrique Macías

Comments: Accepted for publication in A&A Letter
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2510.27468 [astro-ph.EP] (or arXiv:2510.27468v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2510.27468
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Submission history
From: Yu Wang
[v1] Fri, 31 Oct 2025 13:38:01 UTC (1,412 KB)
https://arxiv.org/abs/2510.27468

Astrobiology, Astrochemistry

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

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