A group of astronomers has used the High Acuity Wide-field K-band Imager (HAWK-I), an infrared instrument installed on ESO’s Very Large Telescope (VLT) at the Paranal Observatory in Chile, to produce the deepest and most comprehensive view of a cosmic cloud called the Orion Nebula to date. This stunning image reveals about ten times as many brown dwarfs and planetary-mass objects than were previously known.
This image of the Orion Nebula was obtained from multiple exposures using VLT’s HAWK-I infrared camera. This is the deepest view ever of this region and reveals more very faint planetary-mass objects than expected. Image credit: H. Drass et al / ESO.
The famous Orion Nebula, also known as NGC 1976, Messier 42 (M42), LBN 974, or Sharpless 281, is a diffuse nebula in the constellation of Orion.
It spans about 24 light-years and is located approximately 1,630 light-yearsaway from Earth.
It can be seen with the naked eye as a fuzzy patch surrounding the star Theta Orionis in the Hunter’s Sword, below Orion’s belt.
This glowing cloud had been known since the beginnings of recorded astronomy as a star, but it is so outstanding that it was first noted as an extended nebula in 1610, only a year after Galileo Galilei’s first use of the telescope.
Detailed descriptions of the nebula started appearing later in the 17th century, and it has been a popular target for anyone with a telescope ever since.
Highlights from the spectacular new image of the Orion Nebula. Image credit: H. Drass et al / ESO.
“Understanding how many low-mass objects are found in the Orion Nebula is very important to constrain current theories of star formation,” said team member Dr. Amelia Bayo, an astronomer at the University of Valparaoso in Chile and the Max-Planck Institut für Astronomie in Germany.
“We now realize that the way these very low-mass objects form depends on their environment.”
The new image (hi-res version) of the Orion Nebula has caused excitement because it reveals at least 760 brown dwarfs and 160 isolated planetary-mass objects, which in turn suggests that the nebula may be forming proportionally far more low-mass objects than closer and less active star formation regions.
Scientists count up how many objects of different masses form in regions like the Orion Nebula to try to understand the star-formation process.
Before this research the greatest number of objects were found with masses of about one quarter that of our Sun.
“Our result feels to me like a glimpse into a new era of planet and star formation science,” said team member Dr. Holger Drass, from the Ruhr-Universität Bochum in Germany and the Pontificia Universidad Católica de Chile, who is the lead author of a paper published in the Monthly Notices of the Royal Astronomical Society (arXiv.org preprint).
“The huge number of free-floating planets at our current observational limit is giving me hope that we will discover a wealth of smaller Earth-sized planets with future ESO’s European Extremely Large Telescope.”
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