The inside-out planetary nebula around a born-again star

DOI: 
10.1038/s41550-018-0551-8
Publication date: 
01/08/2018
Main author: 
Guerrero, Martín A.
IAA authors: 
Guerrero, Martín A.;Miranda, Luis F.;Kehrig, Carolina
Authors: 
Guerrero, Martín A.;Fang, Xuan;Miller Bertolami, Marcelo M.;Ramos-Larios, Gerardo;Todt, Helge;Alarie, Alexandre;Sabin, Laurence;Miranda, Luis F.;Morisset, Christophe;Kehrig, Carolina;Zavala, Saúl A.
Journal: 
Nature Astronomy
Refereed: 
Yes
Publication type: 
Article
Pages: 
784-789
Abstract: 
Planetary nebulae are ionized clouds of gas formed by the hydrogen-rich envelopes of low- and intermediate-mass stars ejected at late evolutionary stages. The strong UV flux from their central stars causes a highly stratified ionization structure, with species of higher ionization potential closer to the star. Here, we report on the exceptional case of HuBi 1, a double-shell planetary nebula whose inner shell presents emission from low-ionization species close to the star and emission from high-ionization species farther away. Spectral analysis demonstrates that the inner shell of HuBi 1 is excited by shocks, whereas its outer shell is recombining. The anomalous excitation of these shells can be traced to its low-temperature [WC10] central star whose optical brightness has declined continuously by 10 magnitudes in a period of 46 years. Evolutionary models reveal that this star is the descendant of a low-mass star (≃1.1 M<SUB>☉</SUB>) that has experienced a `born-again' event<SUP>1</SUP> whose ejecta shock-excite the inner shell. HuBi 1 represents the missing link in the formation of metal-rich central stars of planetary nebulae from low-mass progenitors, offering unique insight regarding the future evolution of the born-again Sakurai's object<SUP>2</SUP>. Coming from a solar-mass progenitor, HuBi 1 represents a potential end-state for our Sun.
Database: 
ADS
SCOPUS
URL: 
https://ui.adsabs.harvard.edu/#abs/2018NatAs...2..784G/abstract
ADS Bibcode: 
2018NatAs...2..784G
Keywords: 
Astrophysics - Solar and Stellar Astrophysics