Euclid’s view of the Horsehead Nebula
Euclid shows us a spectacularly panoramic and detailed view of the Horsehead Nebula, also known as Barnard 33 and part of the constellation Orion.
At approximately 1375 light-years away, the Horsehead – visible as a dark cloud shaped like a horse’s head – is the closest giant star-forming region to Earth. It sits just to the south of star Alnitak, the easternmost of Orion’s famous three-star belt, and is part of the vast Orion molecular cloud.
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Many other telescopes have taken images of the Horsehead Nebula, but none of them are able to create such a sharp and wide view as Euclid can with just one observation. Euclid captured this image of the Horsehead in about one hour, which showcases the mission's ability to very quickly image an unprecedented area of the sky in high detail.
In Euclid’s new observation of this stellar nursery, scientists hope to find many dim and previously unseen Jupiter-mass planets in their celestial infancy, as well as young brown dwarfs and baby stars.
“We are particularly interested in this region, because star formation is taking place in very special conditions,” explains Eduardo Martin Guerrero de Escalante of the Instituto de Astrofisica de Canarias in Tenerife and a legacy scientist for Euclid.
These special conditions are caused by radiation coming from the very bright star Sigma Orionis, which is located above the Horsehead, just outside Euclid’s field-of-view (the star is so bright that the telescope would see nothing else if it pointed directly towards it).
Ultraviolet radiation from Sigma Orionis causes the clouds behind the Horsehead to glow, while the thick clouds of the Horsehead itself block light from directly behind it; this makes the head look dark. The nebula itself is made up largely of cold molecular hydrogen, which gives off very little heat and no light. Astronomers study the differences in the conditions for star formation between the dark and bright clouds.
The star Sigma Orionis itself belongs to a group of more than a hundred stars, called an open cluster. However, astronomers don’t have the full picture of all the stars belonging to the cluster. “Gaia has revealed many new members, but we already see new candidate stars, brown dwarfs and planetary-mass objects in this Euclid image, so we hope that Euclid will give us a more complete picture,” adds Eduardo.
Click on the image on the right to discover the location of a free-floating planet in the Horsehead Nebula. The Horsehead is a region in the Orion molecular cloud complex, where star and planet formation are taking place. One example of a free-floating planet is SOri62, a young planet with a mass equal to ten times that of Jupiter. The planet has a temperature of 1200 degrees Celsius and shines bright in infrared light.