The symbiotic star V694 Mon has transitioned from the accreting-only state to the steady burning phase

TL;DR

This paper reports that the symbiotic star V694 Mon transitioned from an accreting-only state to a steady hydrogen-burning phase, leading to significant photometric and spectroscopic changes, with implications for its future activity and white dwarf characteristics.

Contribution

It provides the first evidence of V694 Mon's transition to steady nuclear burning, highlighting its similarity to V4368 Sgr and estimating the white dwarf's mass and luminosity.

Findings

Peak optical brightness reached in early 2024.

Steady hydrogen-burning phase has begun, suppressing jet ejections and flickering.

White dwarf mass estimated at 0.60 solar masses.

Abstract

We propose that the drastic photometric and spectroscopic changes affecting the symbiotic star V694 Mon since 2018, are due to its transition from the accreting-only state to steady hydrogen-burning on the surface of the white dwarf, closely mimicking the pattern followed by V4368 Sgr. The phase of peak optical brightness and weakest emission lines has probably been reached in early 2024. The high-velocity absorptions powered by jet-ejection and the wild flickering, which dominated the century-long quiescence, should not reappear as long has nuclear burning will hold (time-scale of decades). The 3500 Lsun burning luminosity suggests a mass of 0.60 Msun for the WD.