RCW 58

WOLF RAYET STAR IN CARINA - HD 96548 aka WR 40

 (ra 11:06.54/ dec -65:38)

March 2013, Home Backyard in Martínez, Buenos Aires, Argentina

DATA

TYPE: Wolf Rayet Star

Apparent magnitude: 7.7 for HD 96.548

Apparent diameter: 7 arc minutes

Distance: 12.700  light years

IMAGE INFORMATION

SCOPE: Carbon Fiber Ritchey Chrétien 8" f8 

CAMERA: QSI 583 WS

FILTERS: Baader RGB, IDAS LPS for Luminance

SKY CONDITIONS: urban skies + full Moon

EXPOSURES: LHaRGB (60,100,30,30,30)

OBJECT DESCRIPTION AND IMAGE SESSION

Wolf Rayet stars are evolved massive stars which are loosing mass rapidly by means of a very strong stellar winds. In 1867 using a 40 cm telescope from Paris Observatory, astronomers Charles Wolf and George Rayet discovered in the constellation of Cygnus, three stars that displayed broad emission lines. The number of stars with emission lines is quite low, making these type of objects quite unusual, since most stars display absorption lines.

One example of these peculiar objects can be found in the constellation of Carina. In this case RCW 58 is a bubble of gas formed by ejected material blown out from the central star HD 96548 in a continuous spectrum. Helium, nitrogen, carbon and oxygen are expelled at high velocities up to 2400  km/s.   The stellar winds represent a powerful source of mechanical energy and it will have significant effect on the evolution of the nebula.

RCW 58 is a very dim object for a light polluted place as my home backyard... even more complicated to image with a full Moon. Nevertheless with the aid of the Astronomik 6 nm Ha filter I was able to capture some pieces of the shell structure of the ring ejected.