| Téléchargement | - Voir la version finale : Do all low-mass stars undergo extra mixing processes? (PDF, 3.2 Mio)
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| DOI | Trouver le DOI : https://doi.org/10.3847/1538-4357/ac87a6 |
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| Auteur | Rechercher : Balser, Dana S.Identifiant ORCID : https://orcid.org/0000-0002-2465-7803; Rechercher : Wenger, Trey V.1Identifiant ORCID : https://orcid.org/0000-0003-0640-7787; Rechercher : Bania, T. M.Identifiant ORCID : https://orcid.org/0000-0003-4866-460X |
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| Affiliation | - Conseil national de recherches du Canada. Herzberg en astronomie et en astrophysique
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| Format | Texte, Article |
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| Sujet | stellar evolution; planetary nebulae; radio spectroscopy |
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| Résumé | Standard stellar evolution models that only consider convection as a physical process to mix material inside of stars predict the production of significant amounts of ³He in low-mass stars (M < 2 Me), with peak abundances of ³He/H ∼ few × 10−3 by number. Over the lifetime of the Galaxy, this ought to produce ³He/H abundances that diminish with increasing Galactocentric radius. Observations of ³He+ in H II regions throughout the Galactic disk, however, reveal very little variation in the ³He abundance with values of ³He/H similar to the primordial abundance, ( He H 10 / )p 3 5 ~ - . This discrepancy, known as the “³He problem,” can be resolved by invoking in stellar evolution models an extra mixing mechanism due to the thermohaline instability. Here we observe ³He+ in the planetary nebula (PN) J320 (G190.3–17.7) with the Jansky Very Large Array to confirm a previous ³He+ detection made with the Very Large Array that supports standard stellar yields. This measurement alone indicates that not all stars undergo extra mixing. Our more sensitive observations do not detect ³He+ emission from J320 with an rms noise of 58.8 μJy beam−1 after smoothing the data to a velocity resolution of 11.4 km s⁻¹. We estimate an abundance limit of ³He/H ≤ 2.75 × 10−3 by number using the numerical radiative transfer code NEBULA. This result nullifies the last significant detection of ³He+ in a PN and allows for the possibility that all stars undergo extra mixing processes. |
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| Date de publication | 2022-09-12 |
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| Maison d’édition | IOP |
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| Licence | |
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| Dans | |
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| Langue | anglais |
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| Publications évaluées par des pairs | Oui |
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| Exporter la notice | Exporter en format RIS |
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| Signaler une correction | Signaler une correction (s'ouvre dans un nouvel onglet) |
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| Identificateur de l’enregistrement | ec7b2159-62ea-41c1-98bb-cbfb44d20a97 |
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| Enregistrement créé | 2023-11-02 |
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| Enregistrement modifié | 2023-11-02 |
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