Observational constraints for the circumstellar disk of the B[e] star CPD−52 9243⋆
1 Departamento de Espectroscopía, Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, and Instituto de Astrofísica La Plata, CCT La Plata, CONICET Paseo del Bosque S/N, B1900FWA, La Plata Argentina
2 Observatório Nacional – MCTI, Rua General José Cristino 77, 20921–400 São Cristovão, Rio de Janeiro, Brazil
3 Astronomický ústav, Akademie věd České Republiky, Fričova 298, 25165 Ondřejov, Czech Republic
4 Laboratoire Lagrange, UMR7293, Université de Nice Sophia-Antipolis, CNRS, Observatoire de la Côte d’Azur, 06300 Nice, France
5 Departamento de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso, Av. Gran Bretaña 1111, 5030 Casilla Valparaíso, Chile
6 European Southern Observatory, 3107 Alonso de Cordova, Vitacura, Santiago, Chile
Received: 28 July 2012
Accepted: 3 October 2012
Context. The formation and evolution of gas and dust environments around B[e] supergiants are still open issues.
Aims. We intend to study the geometry, kinematics and physical structure of the circumstellar environment (CE) of the B[e] supergiant CPD−52 9243 to provide further insights into the underlying mechanism causing the B[e] phenomenon.
Methods. The influence of the different physical mechanisms acting on the CE (radiation pressure, rotation, bi-stability or tidal forces) is somehow reflected in the shape and kinematic properties of the gas and dust regions (flaring, Keplerian, accretion or outflowing disks). To investigate these processes we mainly used quasi-simultaneous observations taken with high spatial resolution optical long-baseline interferometry (VLTI/MIDI), near-IR spectroscopy of CO bandhead features (Gemini/Phoenix and VLT/CRIRES) and optical spectra (CASLEO/REOSC).
Results. High angular resolution interferometric measurements obtained with VLTI/MIDI provide strong support for the presence of a dusty disk(ring)-like structure around CPD−52 9243, with an upper limit for its inner edge of ~8 mas (~27.5 AU, considering a distance of 3.44 kpc to the star). The disk has an inclination angle with respect to the line of sight of 46 ± 7°. The study of CO first overtone bandhead evidences a disk structure in Keplerian rotation. The optical spectrum indicates a rapid outflow in the polar direction.
Conclusions. The IR emission (CO and warm dust) indicates Keplerian rotation in a circumstellar disk while the optical line transitions of various species are consistent with a polar wind. Both structures appear simultaneously and provide further evidence for the proposed paradigms of the mass-loss in supergiant B[e] stars. The presence of a detached cold CO ring around CPD–52 9243 could be due to a truncation of the inner disk caused by a companion, located possibly interior to the disk rim, clearing the center of the system. More spectroscopic and interferometric data are necessary to determine a possible binary nature of the star.
Key words: supergiants / stars: winds, outflows / stars: mass-loss / circumstellar matter / stars: individual: CPD-52 9243
Based on observations taken with: 1) Telescopes at Paranal ESO Observatory under the program 085.D–0454 and 385.D–0513A; 2) Gemini South/Phoenix instrument, science program GS-2010A-Q-41; 3) J. Sahade Telescope at Complejo Astronómico El Leoncito (CASLEO), operated under an agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina, the Secretaría de Ciencia y Tecnología de la Nación and the National Universities of La Plata, Córdoba and San Juan.
© ESO, 2012