Study of the luminous blue variable star candidate G26.47+0.02 and its environment

S. Paron^1,2,3, J. A. Combi^4,5, A. Petriella^1,3 and E. Giacani^1,2

¹ Instituto de Astronomía y Física del Espacio (IAFE), CC 67, Suc. 28, 1428 Buenos Aires, Argentina
e-mail: sparon@iafe.uba.ar
² FADU – Universidad de Buenos Aires, Ciudad Universitaria, 1428 Buenos Aires, Argentina
³ CBC – Universidad de Buenos Aires, Ciudad Universitaria, 1428 Buenos Aires, Argentina
⁴ Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque, 1900 FWA La Plata, Argentina
⁵ IAR, CONICET, CCT La Plata, C.C. No. 5 (1894) Villa Elisa, Buenos Aires, Argentina

Received: 30 January 2012
Accepted: 1 May 2012

Abstract

Aims. The luminous blue variable (LBV) stars are peculiar very massive stars. The study of these stellar objects and their surroundings is important for understanding the evolution of massive stars and its effects on the interstellar medium. We study the LBV star candidate G26.47+0.02.

Methods. Using several large-scale surveys in different frequencies we performed a multiwavelength study of G26.47+0.02 and its surroundings.

Results. We found a molecular shell (seen in the ¹³CO J = 1–0 line) that partially surrounds the mid-infrared nebula of G26.47+0.02, which suggests an interaction between the strong stellar winds and the molecular gas. From the HI absorption and the molecular gas study we conclude that G26.47+0.02 is located at a distance of  ~4.8 kpc. The radio continuum analysis shows both thermal and non-thermal emission toward this LBV candidate, pointing to wind-wind collision shocks from a binary system. This hypothesis is supported by a search of near-IR sources and the Chandra X-ray analysis. Additional multiwavelength and long-term observations are needed to detect some possible variable behavior, and if that is found, to confirm the binary nature of the system.