THE 2011 PERIASTRON PASSAGE OF THE Be BINARY delta Scorpii

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Miroshnichenko, A. S. ^[1] ; Pasechnik, A. V. ^[2] ; Manset, N. ^[3] ; Carciofi, A. C. ^[4] ; Rivinius, Th. ^[5] ; Stefl, S. ^[6] ; Gvaramadze, V. V. ^{[7, 8]} ; Ribeiro, J. ^[9] ; Fernando, A. ^[10] ; Garrel, T. ^[11] ; Knapen, J. H. ^{[12, 13]} ; Buil, C. ^[14] ; Heathcote, B. ^[15] ; Pollmann, E. ; Mauclaire, B. ^[16] ; Thizy, O. ^[17] ; Martin, J. ^[18] ; Zharikov, S. V. ^[19] ; Okazaki, A. T. ^[20] ; Gandet, T. L. ^[21] ; Eversberg, T. ^[22] ; Reinecke, N.

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^[1] Univ N Carolina, Dept Phys & Astron, Greensboro, NC 27402 - USA

^[2] Univ Turku, Dept Phys & Astron, Tuorla Observ, FI-21500 Pukkio - Finland

^[3] CFHT Corp, Kamuela, HI 96743 - USA

^[4] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508 Sao Paulo - Brazil

^[5] European Org Astron Res Southern Hemisphere, Santiago 19 - Chile

^[6] ESO ALMA, Santiago - Chile

^[7] Moscow MV Lomonosov State Univ, Sternberg Astron Inst, Moscow 119992 - Russia

^[8] Isaac Newton Inst Chile, Moscow Branch, Moscow 119992 - Russia

^[9] Observ Inst Geog Exercito, Lisbon - Portugal

^[10] ATALAIA Org Grp, Lisbon - Portugal

^[11] Observ Juvignac, F-34900 Juvignac - France

^[12] Univ La Laguna, Dept Astrofis, E-38206 Tenerife - Spain

^[13] Inst Astrofis Canarias, E-38205 Tenerife - Spain

^[14] Castanet Tolosan Observ, F-31320 Castanet Tolosan - France

^[15] Barfold Observ, Glenhope, Vic 3444 - Australia

^[16] Observ Val dArc, F-13530 Trets - France

^[17] Shelyak Instruments, F-38330 Saint Ismier - France

^[18] Univ Illinois, Dept Phys & Astron, Barber Res Observ, Springfield, IL 62703 - USA

^[19] Univ Nacl Autonoma Mexico, Inst Astron, Ensenada 22800, Baja California - Mexico

^[20] Hokkai Gakuen Univ, Fac Engn, Toyohira Ku, Sapporo, Hokkaido 0628605 - Japan

^[21] Lizard Hollow Observ, Tucson, AZ 85752 - USA

^[22] Schnorringen Telescope Sci Inst, Waldbrol - Germany

• Tipo de documento: Artigo Científico
• Fonte: ASTROPHYSICAL JOURNAL; v. 766, n. 2 APR 1 2013.
• Citações Web of Science: 6

Resumo

We describe the results of the world-wide observing campaign of the highly eccentric Be binary system delta Scorpii 2011 periastron passage which involved professional and amateur astronomers. Our spectroscopic observations provided a precise measurement of the system orbital period at 10.8092 +/- 0.0005 yr. Fitting of the He II 4686 angstrom line radial velocity curve determined the periastron passage time on 2011 July 3, UT 9:20 with a 0.9-day uncertainty. Both these results are in a very good agreement with recent findings from interferometry. We also derived new evolutionary masses of the binary components (13 and 8.2 M-circle dot) and a new distance of 136 pc from the Sun, consistent with the HIPPARCOS parallax. The radial velocity and profile variations observed in the H alpha line near the 2011 periastron reflected the interaction of the secondary component and the circumstellar disk around the primary component. Using these data, we estimated a disk radius of 150 R-circle dot. Our analysis of the radial velocity variations measured during the periastron passage time in 2000 and 2011 along with those measured during the 20th century, the high eccentricity of the system, and the presence of a bow shock-like structure around it suggest that delta Sco might be a runaway triple system. The third component should be external to the known binary and move on an elliptical orbit that is tilted by at least 40 degrees with respect to the binary orbital plane for such a system to be stable and responsible for the observed long-term radial velocity variations. (AU)

• Processo FAPESP: 10/19029-0 - Modelos tridimensionais de transporte radiativo: uma ponte entre teoria e observações
• Beneficiário: Alex Cavaliéri Carciofi
• Linha de fomento: Auxílio à Pesquisa - Regular