VLT Celebrates Its First Decade of Observations

In the traditional way of marking such events, the European Organization for Astronomical Research in the Southern Hemisphere has published two images of nebulae inside the Carina constellation. The Eta Carinae star with the Homunculus surrounding it is one of the nebulae featured in the pictures.

Eta Carinae is a hypergiant luminous blue variable star and at the same time the most luminous known star in the Milky Way galaxy, with a brightness surpassing that of the Sun by over one million times. It has a mass between 100 and 150 greater than that of the Sun and is expected to go 'nova' in about 100,000 years' time. The nebula surrounding it was partially created during an eruption that could be observed from Earth in 1843.

The other image released by the ESO shows a larger nebula created by a cluster of young massive stars.

During the VLT's First Light a decade ago, the Eta Carinae star was amongst the first objects to be viewed with the test camera of the telescope sitting atop the Paranal mountain. The first image of Eta Carinae had a resolution of only 0.38 arcseconds, while the latest one is at least 6 to 7 times better. It was captured by the NACO instrument of the Unit Telescope 4 of the VLT, also known as Yepun. The NACO near-infrared instrument is able to counter atmospheric distortions, by making use of an adaptive optics system so powerful that it appears as if the Earth had no atmosphere at all.

Homunculus means 'little man' in Latin, and indeed resembles one while viewed with a low power telescope. NACO shows the Homunculus in great detail, as well as the jets of matter expelled into interstellar space by Eta Carinae.

Meanwhile, the second image of a nebula dubbed NGC 3576, located about 9,000 light years away in the Carina constellation was pictured by the ISAAC infrared instrument on the Unit Telescope 1, named Antu. NGC 2576 is 100 light-years across, 25 times more than the distance between the Sun and the closest star, the binary system of Proxima and Alpha Centauri, and is currently home to a series of young stars forming inside it. The nebula is probably about 1.5 million years old.

It presents special interest for astronomical study, since most of the stars forming inside it may still have protoplanetary discs spinning around them and could form planets in the distant future. Determining the proportion of such stars would reveals some of the secrets to how planets come to form and how radiation emitted by the stars influences the dynamics of the protoplanetary discs.