1. Dipper-like variability of the Gaia alerted young star V555 Ori
- Author
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László Mészáros, O. Hanyecz, Gabriella Zsidi, András Pál, Ádám Sódor, Elza Szegedi-Elek, Laszlo Szabados, D. Tarczay-Nehéz, Ágnes Kóspál, Simon Hodgkin, Péter Ábrahám, A. Ordasi, R. Szakats, Gábor Marton, A. Bódi, Csaba Kiss, R. Konyves-Toth, Mária Kun, A. Moór, L. Kriskovics, Zsófia Nagy, B. Ignácz, B. Cseh, Jerome Bouvier, Krisztián Vida, Zsófia Marianna Szabó, Anikó Farkas-Takács, Paula Sarkis, and Krisztián Sárneczky
- Subjects
Physics ,Brightness ,Accretion (meteorology) ,010308 nuclear & particles physics ,Astrophysics::High Energy Astrophysical Phenomena ,Extinction (astronomy) ,FOS: Physical sciences ,Flux ,Astronomy and Astrophysics ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Light curve ,01 natural sciences ,T Tauri star ,Wavelength ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Variation (astronomy) ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics::Galaxy Astrophysics - Abstract
V555 Ori is a T Tauri star, whose 1.5 mag brightening was published as a Gaia science alert in 2017. We carried out optical and near-infrared photometric, and optical spectroscopic observations to understand the light variations. The light curves show that V555 Ori was faint before 2017, entered a high state for about a year, and returned to the faint state by mid-2018. In addition to the long-term flux evolution, quasi-periodic brightness oscillations were also evident, with a period of about 5 days. At optical wavelengths both the long-term and short-term variations exhibited colourless changes, while in the near-infrared they were consistent with changing extinction. We explain the brightness variations as the consequence of changing extinction. The object has a low accretion rate whose variation in itself would not be enough to reproduce the optical flux changes. This behaviour makes V555 Ori similar to the pre-main sequence star AA Tau, where the light changes are interpreted as periodic eclipses of the star by a rotating inner disc warp. The brightness maximum of V555 Ori was a moderately obscured ($A_V$=2.3 mag) state, while the extinction in the low state was $A_V$=6.4 mag. We found that while the Gaia alert hinted at an accretion burst, V555 Ori is a standard dipper, similar to the prototype AA Tau. However, unlike in AA Tau, the periodic behaviour was also detectable in the faint phase, implying that the inner disc warp remained stable in both the high and low states of the system., Accepted to MNRAS
- Published
- 2021
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