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Possible Detection ...
Possible Detection of Gamma-Rays from Epsilon Eridani
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Riley, A. H. (author)
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Strigari, L. E. (author)
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Porter, T. A. (author)
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Blandford, R. D. (author)
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Murgia, S. (author)
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Kerr, M. (author)
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- Jóhannesson, Gudlaugur (author)
- Stockholms universitet,KTH,Nordic Institute for Theoretical Physics NORDITA,Science Institute, University of Iceland, Reykjavik, IS-107, Iceland,Nordiska institutet för teoretisk fysik (Nordita)
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(creator_code:org_t)
- 2019-06-06
- 2019
- English.
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In: Astrophysical Journal. - : Institute of Physics Publishing (IOPP). - 0004-637X .- 1538-4357. ; 878:1
- Related links:
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http://arxiv.org/pdf...
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https://urn.kb.se/re...
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https://doi.org/10.3...
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https://urn.kb.se/re...
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Abstract
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- We use the Fermi Large Area Telescope gamma-ray observatory to search for gamma-ray emission from four nearby, debris disk-hosting main-sequence stars: τ Ceti, Eridani, Fomalhaut, and Vega. For three stars (τ Ceti, Fomalhaut, and Vega), we establish upper limits that are consistent with theoretical expectations. For Eridani, we find a possible spatially coincident source with a soft energy spectrum of dN/dE ∼ E -3.6. However, at this stage we are unable to rule out that this emission is due to a more extended feature in the diffuse background. In the interpretation that the emission is due to Eridani, the >100 MeV gamma-ray luminosity is ∼1027 erg s-1 ≃ 3 ×10-7 L o, which is ∼1010 times the gamma-ray luminosity from the disk of the quiet Sun. We find ≲2σ evidence of source variability over a ∼7 yr timescale. In the interpretation that the gamma-ray emission is from Eridani itself, we consider two possible models: (1) cosmic-ray collisions with solid bodies in the debris disk, which extends out ∼60 au from the host star, and (2) emission from the stellar activity. For the former model, assuming a total disk mass consistent with infrared measurements, we find that the size distribution of bodies is steeper than expected for a collisional cascade state. If confirmed as being associated with Eridani, this would be the first indication of gamma-ray emission from the vicinity of a main-sequence star other than the Sun.
Subject headings
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
- NATURVETENSKAP -- Fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences (hsv//eng)
Keyword
- gamma rays: stars
- protoplanetary disks
Publication and Content Type
- ref (subject category)
- art (subject category)
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