The Be Supergiant CPD -57o2874 Artists View
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The B[e] Supergiant CPD -57o2874 (Artist's View)

December 12, 2005
Another international team of astronomers has just done this kind of observations to study the surroundings of a star entering the last stages of its life. In a world premiere, they combined with AMBER the light of three 8.2-m Unit Telescopes of the VLT, gaining unsurpassed knowledge on a B[e] supergiant, a star that is more luminous than our Sun by more than a factor 10,000. This supergiant star is located ten times further away than MCW 297 at more than 8,000 light-years.

The astronomers made the observations to investigate the crucial questions concerning the origin, geometry, and physical structure of the envelope surrounding the star.

These unique observations have allowed the scientists to see structures on scale as small as 1.8 thousandths of an arcsecond - that is the same as distinguishing between the headlights of a car from about 230,000 km away, or slightly less than 2/3 of the distance from the Earth to the Moon!

Armando Domiciano de Souza, from the MPI fuer Radioastronomie in Bonn (Germany) and his colleagues made also use of the MIDI instrument on the VLTI, using two Unit Telescopes. Using their full dataset, they found the circumstellar envelope around the supergiant to be non-spherical, most probably because the star is also surrounded by an equatorial disc made of hot dust and a strong polar wind.

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