ESO Science Release | VLT | SPHERE | 2015 Nov 25
Giant star caught in the act of slimming down
[img3="Surroundings of VY Canis Majoris - Credit: ESO"]http://cdn.eso.org/images/screen/eso1546a.jpg[/img3][hr][/hr]A team of astronomers using ESO’s Very Large Telescope (VLT) has captured the most detailed images ever of the hypergiant star VY Canis Majoris. These observations show how the unexpectedly large size of the particles of dust surrounding the star enable it to lose an enormous amount of mass as it begins to die. This process, understood now for the first time, is necessary to prepare such gigantic stars to meet explosive demises as supernovae.
VY Canis Majoris is a stellar goliath, a red hypergiant, one of the largest known stars in the Milky Way. It is 30–40 times the mass of the Sun and 300 000 times more luminous. In its current state, the star would encompass the orbit of Jupiter, having expanded tremendously as it enters the final stages of its life.
The new observations of the star used the SPHERE instrument on the VLT. The adaptive optics system of this instrument corrects images to a higher degree than earlier adaptive optics systems. This allows features very close to bright sources of light to be seen in great detail [1]. SPHERE clearly revealed how the brilliant light of VY Canis Majoris was lighting up clouds of material surrounding it.
And by using the ZIMPOL mode of SPHERE, the team could not only peer deeper into the heart of this cloud of gas and dust around the star, but they could also see how the starlight was scattered and polarised by the surrounding material. These measurements were key to discovering the elusive properties of the dust. ...
Large dust grains in the wind of VY Canis Majoris - P. Scicluna et al
- arXiv.org > astro-ph > arXiv:1511.07624 > 24 Nov 2015