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A heatwave of accretion energy traced by masers in the G358-MM1 high-mass protostar


Burns, RA and Sugiyama, K and Hirota, T and Kim, KT and Sobolev, AM and Stecklum, B and MacLeod, GC and Yonekura, Y and Olech, M and Orosz, G and Ellingsen, SP and Hyland, H and Caratti o Garatti, A and Brogan, C and Hunter, TR and Phillips, C and van den Heever, SP and Eisloffel, J and Linz, H and Surcis, G and Chibueze, JO and Baan, W and Kramer, B, A heatwave of accretion energy traced by masers in the G358-MM1 high-mass protostar, Nature Astronomy, 4, (5) pp. 506-510. ISSN 2397-3366 (2020) [Refereed Article]

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© The Author(s), under exclusive licence to Springer Nature Limited 2020

DOI: doi:10.1038/s41550-019-0989-3


High-mass stars are thought to accumulate much of their mass via short, infrequent bursts of disk-aided accretion. Such accretion events are rare and difficult to observe directly but are known to drive enhanced maser emission. In this Letter we report high-resolution, multi-epoch methanol maser observations toward G358.93-0.03, which reveal an interesting phenomenon: the subluminal propagation of a thermal radiation ‘heatwave’ emanating from an accreting high-mass protostar. The extreme transformation of the maser emission implies a sudden intensification of thermal infrared radiation from within the inner (40-mas, 270-au) region. Subsequently, methanol masers trace the radial passage of thermal radiation through the environment at ≥4% of the speed of light. Such a high translocation rate contrasts with the ≤10 km s-1 physical gas motions of methanol masers typically observed using very-long-baseline interferometry (VLBI). The observed scenario can readily be attributed to an accretion event in the high-mass protostar G358.93-0.03-MM1. While being the third case in its class, G358.93-0.03-MM1 exhibits unique attributes hinting at a possible ‘zoo’ of accretion burst types. These results promote the advantages of maser observations in understanding high-mass-star formation, both through single-dish maser monitoring campaigns and via their international cooperation as VLBI arrays.

Item Details

Item Type:Refereed Article
Keywords:SM: individual objects (G358.931-0.030) – ISM: molecules – masers – radio lines: ISM – stars: formation
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Galactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Orosz, G (Mr Gabor Orosz)
UTAS Author:Ellingsen, SP (Professor Simon Ellingsen)
UTAS Author:Hyland, H (Mr Lucas Hyland)
ID Code:140104
Year Published:2020
Funding Support:Australian Research Council (DP180101061)
Web of Science® Times Cited:13
Deposited By:Physics
Deposited On:2020-07-27
Last Modified:2020-08-05

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