New data from the Atacama Large Millimeter/submillimeter Array (ALMA) and other telescopes have been used to create this stunning image showing a web of filaments in the Orion Nebula. These features appear red-hot and fiery in this dramatic picture, but in reality are so cold that astronomers must use telescopes like ALMA to observe them.
The ESOcast Light is a series of short videos bringing you the wonders of the Universe in bite-sized pieces. The ESOcast Light episodes will not be replacing the standard, longer ESOcasts, but complement them with current astronomy news and images in ESO press releases. Credit: ESO
This spectacular and unusual image shows part of the famous Orion Nebula, a star formation region lying about 1350 light-years from Earth. It combines a mosaic of millimeter-wavelength images from the Atacama Large Millimeter/submillimeter Array (ALMA) and the IRAM 30-meter (98-foot) telescope, shown in red, with a more familiar infrared view from the HAWK-I instrument on ESO’s Very Large Telescope, shown in blue. The group of bright blue-white stars at the upper-left is the Trapezium Cluster — made up of hot young stars that are only a few million years old.
The wispy, fiber-like structures seen in this large image are long filaments of cold gas, only visible to telescopes working in the millimeter wavelength range. They are invisible at both optical and infrared wavelengths, making ALMA one of the only instruments available for astronomers to study them. This gas gives rise to newborn stars — it gradually collapses under the force of its own gravity until it is sufficiently compressed to form a protostar — the precursor to a star.
This pan sequence shows part of the famous Orion Nebula star formation region. At the start we see the bright Trapezium Cluster of hot young stars and then see the strange pattern of narrow filaments of cold gas, which appear red in this view from ALMA. The background blue image, which shows the stars and other features, comes from the HAWK-I camera on ESO’s Very Large Telescope. Credit: ESO/H. Drass/A. Hacar/ALMA (ESO/NAOJ/NRAO). Music: Johan B. Monell
The scientists who gathered the data from which this image was created were studying these filaments to learn more about their structure and make-up. They used ALMA to look for signatures of diazenylium gas, which makes up part of these structures. Through this study, the team managed to identify a network of 55 filaments.
The Orion Nebula is the nearest region of massive star formation to Earth, and is therefore studied in great detail by astronomers seeking to better understand how stars form and evolve in their first few million years. ESO’s telescopes have observed this interesting region multiple times, and you can learn more about previous discoveries here, here, and here.
This video starts with a broad view of the sky and zooms in on the familiar constellation of Orion (The Hunter). We then get a closeup view of the Orion Nebula star formation region. In the final sequence we see the strange red filaments of cool gas that ALMA has revealed. Credit: ESO, N. Risinger (skysurvey.org), H. Drass, A. Hacar, ALMA (ESO/NAOJ/NRAO). Music: Johan B. Monell
This image combines a total of 296 separate individual datasets from the ALMA and IRAM telescopes, making it one of the largest high-resolution mosaics of a star formation region produced so far at millimeter wavelengths.
Reference: “An ALMA study of the Orion Integral Filament: I. Evidence for narrow fibers in a massive cloud” by A. Hacar, M. Tafalla, J. Forbrich, J. Alves, S. Meingast, J. Grossschedl and P. S. Teixeira, 7 March 2018, Astronomy & Astrophysics.