Astronomy would be a lot easier if there were no clouds of gas and dust in space. There’d be no need for telescopes with the abilty to see through these thick veils. Alas, space is not only full of things we want to see, but full of things that get in the way.
One thing that astronomers want is a clearer look at the process of star formation. Unfortunately, the very clouds of gas that spawn stars also blot them from our view. In their earliest stages of formation, young wanna-be stars are cloaked in a thick cocoon of gas and dust.
The JWST was built in part to see through thick dust that handicaps other telescopes. So were other telescopes like the ESA’s Euclid space telescope. As part of testing its fine-pointing ability, Euclid took a look at a part of the Orion Molecular Cloud Complex called LDN 1641. It’s a so-called dark cloud about 1300 light years away that’s home to more than 1,000 young stellar objects (YSO).
Even with that many stars, LDN 1641 is still a low density cloud. It also host no massive O or B-type stars, the hottest and most massive stars. One of the reasons LDN 1641 is called a dark cloud is that it lacks these types of massive and extremely luminous stars.
Euclid can see in the near-infrared, and that helps it see through dust. Though visible light from stars is blocked by dust, the dust actually absorbs light and then emits it as infrared. That’s why Euclid can see stars that are otherwise hidden by dust. Its Near-Infrared Spectrometer and Photometer (NISP) can sense the infrared light from the dust.
Several individual stars are circled in the image. The magenta colours near them are outflows from young stellar objects. These outflows are a characteristics of YSOs, and they can carve bubbles out of the surrounding gas and dust. As the jets blast away more and more of the gas, the YSO graduates from a Class 0 protostar, known for being inside a gaseous cocoon, into later stages of stellar evolution.
*This zoomed-in portion of the image shows how detailed Euclid’s images are. It shows a pair of YSOs and their outflows. The star in the bottom right has cleared two cone-shaped regions to the left and right of it, and is spewing a jet of material through the centre of these cones. The jet’s lumpy structure indicates that its magnetic field changes periodically. Image Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by M. Schirmer (MPIA, Heidelberg). LICENCE: CC BY-SA 3.0 IGO or ESA Standard Licence*
The upper left of the leading image shows where the cloud ends, or becomes much thinner, and the Universe beyond the cloud is visible.
This region of the sky was chosen for specific reasons that had little to do with astronomy. In order to test Euclid’s fine-guidance system, the telescope needed to be pointed at a region of the sky where few stars are visible in optical light. This image was captured in September 2023 for this reason. It took five hours of observation to capture it.
Euclid’s primary mission isn’t to observe dark clouds and YSOs. It’s main effort is to create a wide, 3D map of the Universe beyond the Milky Way. It’s all part of the effort to understand dark energy and dark matter, two fundamental aspects of the Universe that confound cosmologists.
Along the way, the space telescope will deliver images like this, and of other interesting regions in the Milky Way, and objects beyond it like distant galaxies. Euclid’s gift to us is more wide-field and detailed images of galaxies than we’re accustomed to. A single Euclid observation can capture an area of sky about 100 times larger than the what the JWST can capture in a single frame. It should be able to image millions of galaxies at once, and its images will be sharp enough to reveal morphological detail in distant galaxies. Things like spiral arms and tidal tails will be visible. Even the globular clusters hosted by galaxies should be visible in detail.
*A stellar tapestry in LDN 1641, courtesy of Euclid. Image Credit: ESA/Euclid/Euclid Consortium/NASA, image processing by M. Schirmer (MPIA, Heidelberg). LICENCE: CC BY-SA 3.0 IGO or ESA Standard Licence*
Euclid launched in July 2023, and its mission is scheduled to last for six years. The space telescope is in a halo orbit at the Sun-Earth Lagrangian point L2.
Interested readers can explore some of its images here.