@article{2022MNRAS.512.4003M,
 abstract = {The central star of the planetary nebula (PN) HuBi 1 has been recently
proposed to have experienced a very late thermal pulse (VLTP),
but the dilution of the emission of the recent ejecta by that of
the surrounding H-rich old outer shell has so far hindered
confirming its suspected H-poor nature. We present here an
analysis of the optical properties of the ejecta in the
innermost regions of HuBi 1 using MEGARA high-dispersion
integral field and OSIRIS intermediate-dispersion long-slit
spectroscopic observations obtained with the 10.4-m Gran
Telescopio de Canarias. The unprecedented tomographic capability
of MEGARA to resolve structures in velocity space allowed us to
disentangle for the first time the H\ensuremathα and
H\ensuremathβ emission of the recent ejecta from that of
the outer shell. The recent ejecta is found to have much higher
extinction than the outer shell, implying the presence of large
amounts of dust. The spatial distribution of the emission from
the ejecta and the locus of key line ratios in diagnostic
diagrams probe the shock excitation of the inner ejecta in HuBi
1, in stark contrast with the photoionization nature of the
H-rich outer shell. The abundances of the recent ejecta have
been computed using the MAPPINGS V code under a shock scenario.
They are found to be consistent with a born-again ejection
scenario experienced by the progenitor star, which is thus
firmly confirmed as a new 'born-again' star.},
 adsnote = {Provided by the SAO/NASA Astrophysics Data System},
 adsurl = {https://ui.adsabs.harvard.edu/abs/2022MNRAS.512.4003M},
 archiveprefix = {arXiv},
 author = {Montoro-Molina, B. and Guerrero, M.~A. and Pérez-Dı́az, B. and Toalá, J.~A. and Cazzoli, S. and Miller Bertolami, M.~M. and Morisset, C.},
 doi = {10.1093/mnras/stac336},
 eprint = {2202.00353},
 journal = {\mnras},
 keywords = {stars: evolution, stars: winds, outflows, ISM: jets and outflows, planetary nebulae: general, planetary nebulae: individual (HuBi 1), Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies},
 month = {May},
 number = {3},
 pages = {4003-4020},
 primaryclass = {astro-ph.SR},
 title = {Chemistry and physical properties of the born-again planetary nebula HuBi 1},
 volume = {512},
 year = {2022}
}