The Unique Helium Nova V445 Puppis Ejected ≫0.001 M⊙ in the Year 2000 and Will Not Become a Type Ia Supernova

V445 Puppis (Nova Puppis 2000) is the only known example of a helium nova, where a layer of helium-rich gas accretes onto the surface of a white dwarf (WD) in a cataclysmic variable, with runaway helium burning making for the nova event. Speculatively, a helium nova can provide one path to produce a...

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Main Author: Bradley E. Schaefer
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/ada38d
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author Bradley E. Schaefer
author_facet Bradley E. Schaefer
author_sort Bradley E. Schaefer
collection DOAJ
description V445 Puppis (Nova Puppis 2000) is the only known example of a helium nova, where a layer of helium-rich gas accretes onto the surface of a white dwarf (WD) in a cataclysmic variable, with runaway helium burning making for the nova event. Speculatively, a helium nova can provide one path to produce a Type Ia supernova (SNIa), within the larger framework of single-degenerate models. Relatively little has been known about V445 Pup, with this work reporting the discovery of the orbital period near 1.87 days. The companion star is 2.65 ± 0.35 R _⊙ in radius as an evolved giant star stripped of its outer hydrogen envelope. The orbital period immediately before the 2000 eruption was ${P}_{{\rm{pre}}}$ = 1.871843 ± 0.000014 days, with a steady period change of (−0.17 ± 0.06) × 10 ^−8 from 1896 to 1995. The period immediately after the nova eruption was P _post = 1.873593 ± 0.000034 days, with a $\dot{P}$ of (−4.7 ± 0.5) × 10 ^−8 . The fractional orbital period change (Δ P / P ) is +935 ± 27 ppm. This restricts the mass of the gases ejected in the nova eruption to be ≫0.001 M _⊙ , and much greater than the mass accreted to trigger the nova. So the WD is losing mass over each eruption cycle, and will not become a SNIa. Further, for V445 Pup and helium novae in general, I collect observations from 136 normal SNIa for which any giant or subgiant companion star would have been detected, yet zero companions are found. This is an independent proof that V445 Pup and helium novae are not SNIa progenitors.
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spelling doaj-art-940843c77b2b4b70a73b810ad48907552025-02-10T08:02:43ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01980115610.3847/1538-4357/ada38dThe Unique Helium Nova V445 Puppis Ejected ≫0.001 M⊙ in the Year 2000 and Will Not Become a Type Ia SupernovaBradley E. Schaefer0https://orcid.org/0000-0002-2659-8763Department of Physics and Astronomy, Louisiana State University , Baton Rouge, LA 70803, USAV445 Puppis (Nova Puppis 2000) is the only known example of a helium nova, where a layer of helium-rich gas accretes onto the surface of a white dwarf (WD) in a cataclysmic variable, with runaway helium burning making for the nova event. Speculatively, a helium nova can provide one path to produce a Type Ia supernova (SNIa), within the larger framework of single-degenerate models. Relatively little has been known about V445 Pup, with this work reporting the discovery of the orbital period near 1.87 days. The companion star is 2.65 ± 0.35 R _⊙ in radius as an evolved giant star stripped of its outer hydrogen envelope. The orbital period immediately before the 2000 eruption was ${P}_{{\rm{pre}}}$ = 1.871843 ± 0.000014 days, with a steady period change of (−0.17 ± 0.06) × 10 ^−8 from 1896 to 1995. The period immediately after the nova eruption was P _post = 1.873593 ± 0.000034 days, with a $\dot{P}$ of (−4.7 ± 0.5) × 10 ^−8 . The fractional orbital period change (Δ P / P ) is +935 ± 27 ppm. This restricts the mass of the gases ejected in the nova eruption to be ≫0.001 M _⊙ , and much greater than the mass accreted to trigger the nova. So the WD is losing mass over each eruption cycle, and will not become a SNIa. Further, for V445 Pup and helium novae in general, I collect observations from 136 normal SNIa for which any giant or subgiant companion star would have been detected, yet zero companions are found. This is an independent proof that V445 Pup and helium novae are not SNIa progenitors.https://doi.org/10.3847/1538-4357/ada38dCataclysmic variable starsClassical novaeType Ia supernovaeSupernova remnants
spellingShingle Bradley E. Schaefer
The Unique Helium Nova V445 Puppis Ejected ≫0.001 M⊙ in the Year 2000 and Will Not Become a Type Ia Supernova
The Astrophysical Journal
Cataclysmic variable stars
Classical novae
Type Ia supernovae
Supernova remnants
title The Unique Helium Nova V445 Puppis Ejected ≫0.001 M⊙ in the Year 2000 and Will Not Become a Type Ia Supernova
title_full The Unique Helium Nova V445 Puppis Ejected ≫0.001 M⊙ in the Year 2000 and Will Not Become a Type Ia Supernova
title_fullStr The Unique Helium Nova V445 Puppis Ejected ≫0.001 M⊙ in the Year 2000 and Will Not Become a Type Ia Supernova
title_full_unstemmed The Unique Helium Nova V445 Puppis Ejected ≫0.001 M⊙ in the Year 2000 and Will Not Become a Type Ia Supernova
title_short The Unique Helium Nova V445 Puppis Ejected ≫0.001 M⊙ in the Year 2000 and Will Not Become a Type Ia Supernova
title_sort unique helium nova v445 puppis ejected 0 001 m⊙ in the year 2000 and will not become a type ia supernova
topic Cataclysmic variable stars
Classical novae
Type Ia supernovae
Supernova remnants
url https://doi.org/10.3847/1538-4357/ada38d
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