Published online by Cambridge University Press: 12 April 2016
We present the first high resolution observations of the ring nebula around the galactic LBV AG Car obtained through broad band B, V, R, I filters with the STScI coronograph on the ESO 2.2 m. telescope. Highly anisotropic continuum emission in all these bands is clearly detected, in the shape of a bipolar structure elongated along the NE-SW direction extending from a few arcsecs from the star out to ⋍ 15 arcsecs corresponding to a projected linear distance of ⋍ 0.5 parsecs, with a surface brightness in the range 17.9-19.4 mag/arcsec2. Its essentially neutral color with respect to the star Δ(V-I) = −0.07) suggests that the observed radiation is starlight scattered by dust grains of diameter > 1μ.
On leave from the Observatory of Padova, Italy.
Affiliated to the Astrophysics Division, Space Science Department, ESA
Based on data collected at the European Southern Observatory, La Silla, Chile.