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

Authors :
Munari, U
Joshi, V
Banerjee, D P K
Čotar, K
Shugarov, S Y
Jurdana-Šepić, R
Belligoli, R
Bergamini, A
Graziani, M
Righetti, G L
Vagnozzi, A
Valisa, P
Source :
Monthly Notices of the Royal Astronomical Society; Oct2019, Vol. 488 Issue 4, p5536-5550, 15p
Publication Year :
2019

Abstract

We have been monitoring, at high cadence, the photometric and spectroscopic evolution of VES 263 following the discovery in 2018 of a brightening labelled 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 semiregular AGB cool giant by automated analysis of ASASSN light curves. We have discovered that VES 263 is a bona fide massive pre-main-sequence object (∼12 M<subscript>⊙</subscript>), 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 [ E(B − 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 ≥ 6  |$\mu$| m by emission from circumstellar warm dust (T  ≤ 400 K). The 2018–19 eruption was caused by a marked brightening of the accretion disc 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 disc has a bulk temperature of ∼7500 K and a luminosity L  ≥ 860 L<subscript>⊙</subscript>, corresponding to a mass accretion rate |$\dot{M}$|  ≥ 1.1 × 10<superscript>−5</superscript> M<subscript>⊙</subscript> yr<superscript>−1</superscript>. Spectroscopic signatures of possible bipolar jets (at −700 and +700 km s<superscript>−1</superscript>) 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. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00358711
Volume :
488
Issue :
4
Database :
Complementary Index
Journal :
Monthly Notices of the Royal Astronomical Society
Publication Type :
Academic Journal
Accession number :
138318269
Full Text :
https://doi.org/10.1093/mnras/stz2078