000002211 001__ 2211
000002211 005__ 20160701171701.0
000002211 0247_ $$2DOI$$a10.1111/j.1365-2966.2012.21081.x
000002211 037__ $$aASTROimport-368
000002211 100__ $$aDe Becker, M.
000002211 245__ $$aThe long-period eccentric orbit of the particle accelerator HD 167971 revealed by long baseline interferometry
000002211 260__ $$c2012
000002211 520__ $$aUsing optical long baseline interferometry, we resolved for the first time the two wide components of HD 167971, a candidate hierarchical triple system known to efficiently accelerate particles. Our multi-epoch Very Large Telescope Interferometer observations provide direct evidence for a gravitational link between the O8 supergiant and the close eclipsing O + O binary. The separation varies from 8 to 15 mas over the 3-year baseline of our observations, suggesting that the components evolve on a wide and very eccentric orbit (most probably e > 0.5). These results provide evidence that the wide orbit revealed by our study is not coplanar with the orbit of the inner eclipsing binary. From our measurements of the near-infrared luminosity ratio, we constrain the spectral classification of the components in the close binary to be O6-O7, and confirm that these stars are likely main-sequence objects. Our results are discussed in the context of the bright non-thermal radio emission already reported for this system, and we provide arguments in favour of a maximum radio emission coincident with periastron passage. HD 167971 turns out to be an efficient O-type particle accelerator that constitutes a valuable target for future high angular resolution radio imaging using Very Long Baseline Interferometry facilities. Based on observations collected at the European Southern Observatory, Paranal, Chile, under the programme IDs 381.D-0095, 086.D-0586 and 087.D-0264. 
000002211 700__ $$a Sana, H.
000002211 700__ $$a Absil, O.
000002211 700__ $$a Le Bouquin, J.-B.
000002211 700__ $$a Blomme, R.
000002211 773__ $$c2711-2717$$i3$$pMonthly Notices of the Royal Astronomical Society$$v423$$y2012
000002211 85642 $$ahttp://esoads.eso.org/abs/2012MNRAS.423.2711D
000002211 905__ $$apublished in
000002211 980__ $$aREFERD