A close encounter of the massive kind

• Autores: Maíz Apellániz, Jesús; Sana, H.; Barba, Rodolfo Hector; Le Bouquin, J.B.; Gamen, Roberto Claudio
• Año de publicación: 2017
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Ciencias Astronómicas; Ephemerides; Binaries: Visual; Stars: Individual: Hd 93 129 Aa,Ab; Stars: Kinematics And Dynamics; Stars: Winds, Outflows; X-Rays: Stars.
• Institución: Universidad Nacional de La Plata

We have used (a) HST ACS imaging and STIS spectroscopy, (b) ground-basedPIONIER/VLT long-baseline interferometry, and (c) ground-basedspectroscopy from different instruments to study the orbit of theextreme 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 that willpass through periastron in 2017/2018. In several ways, the system is aneta Car precursor. Around the time of periastron passage the two verystrong winds will collide and generate an outburst of non-thermal hardX-ray emission without precedent in an O+O binary since astronomers havebeen able to observe above Earth's atmosphere. A coordinatedmultiwavelength monitoring in the next two years will enable abreakthrough understanding of the wind interactions in such extremeclose encounters. Furthermore, we have found evidence that HD 93 129 Aamay be a binary system itself. In that case, we could witness athree-body interaction that may yield a runaway star or a stellarcollision close to or shortly after the periastron passage. Either ofthose outcomes would be unprecedented, as they are predicted to below-frequency events in the Milky Way.
Instituto de Astrofísica de La Plata