000007244 001__ 7244
000007244 005__ 20250106163029.0
000007244 0247_ $$2DOI$$a  10.1051/0004-6361/202450496 
000007244 037__ $$aSCART-2025-0020
000007244 100__ $$aHajduk, M.
000007244 245__ $$aNon-thermal radio emission in Sakurai's Object
000007244 260__ $$c2024
000007244 520__ $$aContext. The very late thermal pulse (VLTP) affects the evolution of ∼20% of 1-8 M⊙ stars, repeating the last red giant phases within a few years and leading to the formation of a new, but hydrogen-poor, nebula within the old planetary nebula. The strong dust formation in the latter obscures the optical and near-infrared radiation of the star. Aims: We aimed to determine the reheating timescale of the central star in Sakurai's Object, which is an important constraint for the poorly understood VLTP evolution. Methods: We observed the radio continuum emission of Sakurai's Object for almost 20 years, from 2004 to 2023. Continuous, multi-frequency observations proved to be essential for distinguishing between phases dominated by photoionization and shock ionization. Results: The flux density fluctuates by more than a factor of 40 within months to years. The spectral index remained negative between 2006 and 2017 and has been close to zero since 2019. The emission region has been only barely resolved since 2021. Conclusions: Non-thermal radio emission observed from 2004 to 2017 traces shocks induced by wind interactions due to discrete mass-loss events. Thermal emission dominates from 2019 to 2023 and may indicate photoionization of the nebula by the central star.
000007244 594__ $$aNO
000007244 6531_ $$astars: evolution; stars: jets; stars: mass-loss; stars: winds; outflows; planetary nebulae: general; planetary nebulae: individual: Sakurai's Object; Astrophysics - Solar and Stellar Astrophysics
000007244 700__ $$avan Hoof, P. A. M.
000007244 700__ $$aZijlstra, A. A.
000007244 700__ $$aVan de Steene, G.
000007244 700__ $$aKimeswenger, S.
000007244 700__ $$aBarría, D.
000007244 700__ $$aTafoya, D.
000007244 700__ $$aToalá, J. A.
000007244 773__ $$c21-26$$nL$$pAstronomy & Astrophysics, Volume 688, id.L21, 6 pp.$$v688$$y2024
000007244 8560_ $$fgriet.vandesteene@ksb-orb.be
000007244 85642 $$ahttps://ui.adsabs.harvard.edu/abs/2024A%26A...688L..21H/abstract
000007244 905__ $$apublished in
000007244 980__ $$aREFERD