radiation mechanisms: non-thermal; radiation mechanisms: thermal; radio continuum: ISM; stars: individual: WR 114 and WR 142; stars: Wolf-Rayet; Radiation mechanism: thermal; Radiation mechanisms: nonthermal; Radio continuum: ISM; Star: individual: wolf-rayet 114 and wolf-rayet 142; Stars: Be; Stars: individual: proxima Centauri; Stars: Wolf-Rayet; Wolf-Rayet; Wolf-Rayet stars; Astronomy and Astrophysics; Space and Planetary Science
Abstract :
[en] Large wind kinetic power of Wolf-Rayet (WR) stars make them ideal targets in low radio frequencies to search for non-thermal emission due to relativistic particle acceleration. In this paper, we present observations of two WR stars, WR 114 and WR 142, in Band 4 (550-950 MHz) and Band 5 (1050-1450 MHz) using the upgraded Giant Meterwave Radio Telescope. Neither star is detected in the observed frequency bands, nor extended emission associated with them. The upper limit to the free-free radio emission from the stellar wind enables us to constrain the mass-loss rate of WR 114 to; this is a factor three smaller than previously estimated using spectroscopic modelling. If we further assume that the WR stars are binaries, the non-detection of synchrotron emission from the putative wind collision region implies that the stars are either in very wide binary systems away from periastron, or that the stars are in close binary systems with an orbital separation <70 AU for WR 114 and <20 AU for WR 142. The non-detection of low-frequency radio emission from these two systems thus provides evidence that narrows their nature, though it does not rule them out as bona fide particle-accelerating colliding-wind binaries.
Research center :
STAR - Space sciences, Technologies and Astrophysics Research - ULiège [BE]
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Saha, Anindya ; Indian Institute of Space Science and Technology, Thiruvananthapuram, India
Tej, Anandmayee ; Indian Institute of Space Science and Technology, Thiruvananthapuram, India
Del Palacio, Santiago ; Department of Space Earth and Environment, Chalmers University of Technology, Gothenburg, Sweden
De Becker, Michaël ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO) > Sciences spatiales
Benaglia, Paula; Instituto Argentino de Radioastronomía (CCT La Plata), CONICET, CICPBA, UNLP, Villa Elisa, Argentina
Ishwara-Chandra, C.H.; National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune, India
Prajapati, Prachi; Physical Research Laboratory (PRL), Ahmedabad, India
Language :
English
Title :
Search for particle acceleration in two massive Wolf-Rayet stars using uGMRT observations
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