Evolutionary tracks of massive stars during formation

Smith, Michael D. (2014) Evolutionary tracks of massive stars during formation. Monthly Notices of the Royal Astronomical Society, 438 (2). pp. 1051-1066. ISSN 0035-8711. (doi:https://doi.org/10.1093/mnras/stt2210) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Official URL
http://www.dx.doi.org/10.1093/mnras/stt2210

Abstract

A model for massive stars is constructed by piecing together evolutionary algorithms for the protostellar structure, the environment, the inflow and the radiation feedback. We investigate specified accretion histories of constant, decelerating and accelerating forms and consider both hot and cold accretion, identified with spherical free-fall and disc accretion, respectively. Diagnostic tools for the interpretation of the phases of massive star formation and testing the evolutionary models are then developed. Evolutionary tracks able to fit Herschel Space Telescope data require the generated stars to be three to four times less massive than in previous interpretations, thus being consistent with clump star formation efficiencies of 10–15 per cent. However, for these cold Herschel clumps, the bolometric temperature is not a good diagnostic to differentiate between accretion models. We also find that neither spherical nor disc accretion can explain the high radio luminosities of many protostars. Nevertheless, we discover a solution in which the extreme ultraviolet flux needed to explain the radio emission is produced if the accretion flow is via free-fall on to hotspots covering less than 10 per cent of the surface area. Moreover, the protostar must be compact, and so has formed through cold accretion. We show that these conclusions are independent of the imposed accretion history. This suggests that massive stars form via gas accretion through discs which, in the phase before the star bloats, download their mass via magnetic flux tubes on to the protostar.

Item Type: Article
Uncontrolled keywords: HII regions, ISM: jets and outflows, Stars: formation, Stars: massive, Stars: pre-main-sequence, Stars: protostars
Subjects: Q Science > QB Astronomy > QB460 Astrophysics
Divisions: Faculties > Sciences > School of Physical Sciences > Centre for Astrophysics and Planetary Sciences
Depositing User: Giles Tarver
Date Deposited: 10 Aug 2015 15:42 UTC
Last Modified: 11 Aug 2015 10:21 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/50080 (The current URI for this page, for reference purposes)
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