Published in

Oxford University Press (OUP), Monthly Notices of the Royal Astronomical Society, 2019

DOI: 10.1093/mnras/stz2078

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The 2018 eruption and long term evolution of the new high-mass Herbig Ae/Be object Gaia-18azl = VES 263

This paper was not found in any repository, but could be made available legally by the author.
This paper was not found in any repository, but could be made available legally by the author.

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Data provided by SHERPA/RoMEO

Abstract

Abstract We have been monitoring, at high cadence, the photometric and spectroscopic evolution of VES 263 following the discovery in 2018 of a brightening labeled as event Gaia-18azl. VES 263 is so far a neglected emission-line object discovered in the 1960s on objective prism plates, tentatively classified as a semi-regular AGB cool giant by automated analysis of ASASSN lightcurves. We have discovered that VES 263 is a bonafide massive pre-Main Sequence object (∼12 M⊙), of the Herbig AeBe type. It is located at 1.68±0.07 kpc distance, within the Cyg OB2 star-forming region, and it is highly reddened (EB − V=1.80±0.05) by interstellar extinction. In quiescence, the spectral energy distribution is dominated by the ∼20,000 K photospheric emission from the central B1II star, and at λ≥6μm by emission from circumstellar warm dust (T≤400○K). The 2018-19 eruption was caused by a marked brightening of the accretion disk around the B1II star as traced by the evolution with time of the integrated flux and the double-peaked profile of emission lines. At the peak of the eruption, the disk has a bulk temperature of ∼7500 K and a luminosity L ≥860 L⊙, corresponding to a mass accretion rate M≥1.1 × 10−5 M⊙ yr−1. Spectroscopic signature of possible bipolar jets (at −700 and +700 km s−1) of variable intensity are found. We have reconstructed from Harvard, Moscow and Sonneberg photographic plates the photometric history of VES 263 from 1896 to 1995.