%0 Journal Article %T A close encounter of the massive kind %+ Institut de Planétologie et d'Astrophysique de Grenoble (IPAG) %A Maíz Apellániz, J. %A Sana, H. %A Barbá, R. H. %A Le Bouquin, J. -B. %A Gamen, R. C. %< avec comité de lecture %@ 0035-8711 %J Monthly Notices of the Royal Astronomical Society %I Oxford University Press (OUP): Policy P - Oxford Open Option A %V 464 %P 3561-3567 %8 2017 %D 2017 %Z 1609.08521 %Z 2017MNRAS.464.3561M %R 10.1093/mnras/stw2618 %K ephemerides %K binaries: visual %K stars: individual: HD 93 129 Aa %K Ab %K stars: kinematics and dynamics %K stars: winds %K outflows %K X-rays: stars %K Astrophysics - Solar and Stellar Astrophysics %Z Sciences of the Universe [physics] %Z Sciences of the Universe [physics]/Astrophysics [astro-ph]Journal articles %X We have used (I) Hubble Space Telescope Advanced Camera for Surveys imaging and Space Telescope Imaging Spectrograph spectroscopy, (II) ground-based Precision Integrated-Optics Near-infrared Imaging ExpeRiment/Very Large Telescope long-baseline interferometry, and (III) ground-based spectroscopy from different instruments to study the orbit of the extreme multiple system HD 93 129 Aa,Ab, which is composed of (at least) two very massive stars in a long-period orbit with e > 0.92, which will pass through periastron in 2017/2018. In several ways, the system is an η Car precursor. Around the time of periastron passage, the two very strong winds will collide and generate an outburst of non-thermal hard X-ray emission without precedent in an O+O binary since astronomers have been able to observe above Earth's atmosphere. A coordinated multiwavelength monitoring in the next two years will enable a breakthrough understanding of the wind interactions in such extreme close encounters. Furthermore, we have found evidence that HD 93 129 Aa may be a binary system itself. In that case, we could witness a three-body interaction which may yield a runaway star or a stellar collision close to or shortly after the periastron passage. Either of those outcomes would be unprecedented, as they are predicted to be low-frequency events in the Milky Way. %G English %2 https://insu.hal.science/insu-03692538/document %2 https://insu.hal.science/insu-03692538/file/stw2618.pdf %L insu-03692538 %U https://insu.hal.science/insu-03692538 %~ INSU %~ UNIV-SAVOIE %~ UGA %~ CNRS %~ INPG %~ IRSTEA %~ CNES %~ OSUG %~ IPAG %~ AGREENIUM %~ INRAE %~ UGA-COMUE %~ USMB-COMUE