First Images of the Molecular Gas around a Born-again Star Revealed by ALMA
Artikel i vetenskaplig tidskrift, 2022

Born-again stars allow probing stellar evolution in human timescales and provide the most promising path for the formation of hydrogen-deficient post-asymptotic giant branch objects, but their cold and molecular components remain poorly explored. Here we present ALMA observations of V 605 Aql that unveil for the first time the spatio-kinematic distribution of the molecular material associated with a born-again star. Both the continuum and molecular line emission exhibit a clumpy ring-like structure with a total extent of approximate to 1 '' in diameter. The bulk of the molecular emission is interpreted as being produced in a radially expanding disk-like structure with an expansion velocity v(exp) similar to 90 km s(-1) and an inclination i approximate to 60 degrees with respect to the line of sight. The observations also reveal a compact high-velocity component, v(exp) similar to 280 km s(-1), that is aligned perpendicularly to the expanding disk. This component is interpreted as a bipolar outflow with a kinematical age tau less than or similar to 20 yr, which could either be material that is currently being ejected from V 605 Aql, or is being dragged from the inner parts of the disk by a stellar wind. The dust mass of the disk is in the range M-dust similar to 0.2-8 x 10(-3) M-circle dot, depending on the dust absorption coefficient. The mass of the CO is MCO approximate to 1.1 x 10(-5) M-circle dot, which is more than three orders of magnitude larger than the mass of the other detected molecules. We estimate a C-12/C-13 ratio of 5.6 +/- 0.6, which is consistent with the single stellar evolution scenario in which the star experienced a very late thermal pulse instead of a nova-like event as previously suggested.


Daniel Tafoya

Chalmers, Rymd-, geo- och miljövetenskap, Onsala rymdobservatorium

Jesus A. Toala

Universidad Nacional Autónoma de México

Ramlal Unnikrishnan

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik

Wouter Vlemmings

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik

Martin A. Guerrero

Instituto de Astrofisica de Andalucía (IAA)

Stefan Kimeswenger

University of Innsbruck

Universidad Catolica del Norte

Peter A. M. van Hoof

Royal Observatory of Belgium

Luis A. Zapata

Universidad Nacional Autónoma de México

Sandra Treviño Morales

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik

Janis B. Rodriguez-Gonzalez

Universidad Nacional Autónoma de México

Astrophysical Journal Letters

2041-8205 (ISSN) 2041-8213 (eISSN)

Vol. 925 1 L4


Astronomi, astrofysik och kosmologi

Fusion, plasma och rymdfysik

Den kondenserade materiens fysik



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