--- your online source for astronomical & satellite images ---
The Orion Nebula and Cluster
from the VLT Survey Telescope
Orion Nebula, M42
Emission Nebula, H II Region
RA 5h 35m 8.26s Dec -5° 28' 43.32"
59.95 x 46.56 arcminutes
North is 0.2° left of vertical
July 27, 2017
Other views of the Orion Nebula:
N0601a N0601q N0801sp N1006es N1625eo N1723eo
Click the image to buy a print
ABOUT THIS IMAGE:
Using new observations from ESOs VLT Survey Telescope, astronomers have discovered three different populations of young stars within the Orion Nebula Cluster. This unexpected discovery adds very valuable new insights for the understanding of how such clusters form. It suggests that star formation might proceed in bursts, where each burst occurs on a much faster time-scale than previously thought.
OmegaCAM the wide-field optical camera on ESOs VLT Survey Telescope (VST) has captured the spectacular Orion Nebula and its associated cluster of young stars in great detail, producing a beautiful new image. This object is one of the closest stellar nurseries for both low and high-mass stars, at a distance of about 1350 light-years .
But this is more than just a pretty picture. A team led by ESO astronomer Giacomo Beccari has used these data of unparallelled quality to precisely measure the brightness and colors of all the stars in the Orion Nebula Cluster. These measurements allowed the astronomers to determine the mass and ages of the stars. To their surprise, the data revealed three different sequences of potentially different ages.
Looking at the data for the first time was one of those Wow! moments that happen only once or twice in an astronomer's lifetime, says Beccari, lead author of the paper presenting the results. The incredible quality of the OmegaCAM images revealed without any doubt that we were seeing three distinct populations of stars in the central parts of Orion.
Monika Petr-Gotzens, co-author and also based at ESO Garching, continues, This is an important result. What we are witnessing is that the stars of a cluster at the beginning of their lives didnt form altogether simultaneously. This may mean that our understanding of how stars form in clusters needs to be modified.
The astronomers looked carefully at the possibility that instead of indicating different ages, the different brightnesses and colors of some of the stars were due to hidden companion stars, which would make the stars appear brighter and redder than they really were. But this idea would imply quite unusual properties of the pairs, which have never before been observed. Other measurements of the stars, such as their rotation speeds and spectra, also indicated that they must have different ages .
Although we cannot yet formally disprove the possibility that these stars are binaries, it seems much more natural to accept that what we see are three generations of stars that formed in succession, within less than three million years, concludes Beccari.
new results strongly suggest that star formation in the Orion Nebula Cluster
is proceeding in bursts, and more quickly than had been previously thought.
 The Orion Nebula has been studied by many of ESOs telescopes, including images in visible light from the MPG/ESO 2.2-meter telescope (eso1103) and infrared images from VISTA (eso1701) and the HAWK-I instrument on the Very Large Telescope (eso1625).
 The group also found that each of the three different generations rotate at different speeds the youngest stars rotate the fastest, and the oldest stars rotate the slowest. In this scenario, the stars would have formed in quick succession, within a time frame of three million years.