New deep space images show violent cosmic wind collision in Eta Carinae

19 Oct 2016

The massive star Eta Carinae. Image: NASA

A team of international scientists from Ireland, Germany and the US has managed to generate the sharpest images of one of the heaviest stars in our galaxy, showing the violent collision of cosmic winds in stunning detail.

The deep space study was a collaborative effort between Trinity College Dublin (TCD), the Max Planck Institute for Radio Astronomy (MPIfR) in Germany, and NASA; analysing the cosmic destruction around the Eta Carinae star in the Milky Way.

Eta Carinae is one of the biggest stars in our galaxy, shining with a power equivalent to 5m suns. It is surrounded by the Homunculus Nebula, containing the remains of material ejected in 1843 when Eta Carinae was one of the brightest stars in the sky.

Right in the heart of this nebula, another monster companion star is evaporating while it orbits Eta Carinae, blowing powerful outflows.

These outflows are colliding at a mind-boggling speed of 10m kph, heralding the end of a star’s life as a supernova.

This sighting in deep space gave the international team of scientists the chance to photograph and analyse clues about how such stars evolve and die.

Eta Carinae imags

From left: Eta Carinae’s Homunculus Nebula. To the right, zooming in 500x, the new high-resolution image of the heart of Eta Carinae, showing the collision between the two winds. This region is about 100 times larger than the diameter of each of the two stars. The yellow ellipse is the binary orbit. The two red dots indicate the positions of the two stars at the time of observation. Image: ESO/Gerd Weigelt

Images of unprecedented quality

Thankfully, the MPIfR team in Germany had access to the incredibly powerful European Southern Observatory (ESO) telescopes that are capable of seeing farther into space than many others.

Using a new imaging technique called interferometry, which combines the light from three 1.8-metre telescopes at the ESO’s Very Large Telescope, the team obtained extremely sharp images comparable to a much larger 130-metre telescope.

These results has offered the researchers – and astronomy overall – unprecedented quality images. In the past, it was not possible to resolve this violent collision zone as its extension was too small even for the largest of telescopes.

‘Our dreams came true’

TCD astrophysics professor Jose Groh said of the new images: “We were able to zoom in and see the heavyweight champion in our galaxy like never before. The images provide us with a front-row view of how monster stars interact with each other. The heavier star is winning for now, but the faster companion star may change the fate of the system in the future.”

The leader of the research project, Prof Gerd Weigelt from MPIfR added: “Our dreams came true, because we can now get extremely sharp images in the infrared regime. The ESO interferometer provides us with a unique opportunity to improve our physical understanding of Eta Carinae and many other monster objects.”

Despite discussions being held earlier this year with the ESO, Ireland is yet to sign up as a member to ESO. However, director general Prof Tim de Zeeuw has previously said there had been constructive talks with the Irish Government on joining.

The team’s research has now been published in the journal Astronomy and Astrophysics.

Colm Gorey was a senior journalist with Silicon Republic