VLT Archives

September 17, 2023September 17, 2023 by Scott Alan Johnston

A Collection of New Images Reveal X-Rays Across the Universe

NASA/CXC/SAO, JPL-Caltech, MSFC, STScI, ESA/CSA, SDSS, ESO.

One of the miracles of modern astronomy is the ability to ‘see’ wavelengths of light that human eyes can’t. Last week, astronomers put that superpower to good use and released five new images showcasing the universe in every wavelength from X-ray to infrared.

Combining data from both Earth- and ground-based telescopes, the five images reveal a diverse set of astronomical phenomena, including the galactic centre, the death throes of stars, and distant galaxies traversing the cosmos.

August 24, 2023August 24, 2023 by Matt Williams

One of Neptune's Dark Spots Finally Seen From Earth

This image shows Neptune observed with the MUSE instrument at ESO’s Very Large Telescope (VLT). Credit: ESO/P. Irwin et al.

There’s no getting around it: our Solar System’s gas giants all have big, conspicuous spots on their faces. These include Jupiter’s Great Red Spot, Saturn’s Great White Spot, Uranus’ Great Dark Spot, and Neptune’s Great Dark Spot. Far from blemishes or features that tarnish the planets’ natural beauty, these “spots” are caused by massive storms or other processes in the planets’ atmospheres. While they are extremely large by Earth standards, they are difficult to study by anything other than robotic probes that can get close to the planet.

Neptune’s Great Dark Spot was not discovered until NASA’s Voyager 2 probe flew past the planet in 1989 on its way to the edge of the Solar System. Decades later, scientists are still unsure how this storm originated or what mechanisms drive it today. Using the ESO’s Very Large Telescope (VLT), a team of astronomers was able to observe the Great Dark Spot for the first time using a ground-based telescope. Their results provided the most detailed data on the spot to date and some interesting insights into the nature and origin of this mysterious feature.

July 13, 2023July 13, 2023 by Matt Williams

How Old is That Star? Ask a Computer

An open cluster of stars known as IC 4651, a stellar grouping that lies at in the constellation of Ara (The Altar). Credit: ESO

When measuring distances in the Universe, astronomers rely on what is known as the “Distance Ladder” – a succession of methods by which distances are measured to objects that are increasingly far from us. But what about age? Knowing with precision how old stars, star clusters, and galaxies are is also paramount to determining how the cosmos has evolved. Thanks to a new machine learning technique developed by researchers from Keele University, astronomers may have established the first rung on a “cosmic age ladder.”

March 22, 2023March 22, 2023 by Nancy Atkinson

Another Look at the Aftermath of DART's Impact Into Dimorphos

This artist’s illustration shows the ejection of a cloud of debris after NASA’s DART spacecraft collided with the asteroid Dimorphos. Credit: ESO/M. Kornmesser

When the DART spacecraft slammed into asteroid Dimorphos on September 26, 2022, telescopes worldwide (and in space) were watching as it happened. But others continued watching for numerous days afterward to observe the cloud of debris. DART’s (Double Asteroid Redirection Test) intentional impact was not only a test of planetary defense against an asteroid hitting our planet, but it also allowed astronomers the chance to study Dimorphos, a tiny moon or companion to asteroid Didymos.

New images released by the European Southern Observatory’s Very Large Telescope (VLT) show how the surface of the asteroid changed immediately after the impact when pristine materials from the interior of the asteroid were exposed. Other data tracked the debris’ evolution over a month, and provided details on how the debris changed over time. Additionally, astronomers searched for evidence of DART’s fuel but couldn’t find any.

March 14, 2023March 14, 2023 by Matt Williams

Warm Carbon Increased Suddenly in the Early Universe. Made by the First Stars?

While previous studies have suggested a rise in warm carbon, much larger samples – the basis of the new study – were needed to provide statistics to accurately measure the rate of this growth.

According to the most widely-accepted model of cosmology, the Universe began roughly 13.8 billion years ago with the Big Bang. As the Universe cooled, the fundamental laws of physics (the electroweak force, the strong nuclear force, and gravity) and the first hydrogen atoms formed. By 370,000 years after the Big Bang, the Universe was permeated by neutral hydrogen and very few photons (the Cosmic Dark Ages). During the “Epoch of Reionization” that followed, the first stars and galaxies formed, reoinizing the neutral hydrogen and causing the Universe to become transparent.

For astronomers, the Epoch of Reionization still holds many mysteries, like when certain heavy elements formed. This includes the element carbon, a key ingredient in the formation of planets, an important element in organic processes, and the basis for life as we know it. According to a new study by the ARC Center of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), it appears that triply-ionized carbon (C iv) existed far sooner than previously thought. Their findings could have drastic implications for our understanding of cosmic evolution.

March 2, 2023March 2, 2023 by Matt Williams

A Very Young Star is Forming Near the Milky Way's Supermassive Black Hole

Artist's impression of a young, massive star orbiting Sagittarius A*. Credit: University of Cologne

Since the 1930s, physicists and radio engineer Karl Jansky reported discovering a persistent radio source coming from the center of our galaxy. This source came to be known as Sagittarius A* (Sgr A*), and by the 1970s, astronomers determined that it was a supermassive black hole (SMBH) roughly four million times the mass of our Sun. Since then, astronomers have used increasingly-advanced radio telescopes to study Sgr A* and its surrounding environment. This has led to many exotic discoveries, such as the many “Stars stars” and gaseous “G objects” that orbit it.

The study of these objects and how the powerful gravity of Sgr A* has allowed scientists to test the laws of physics under the most extreme conditions. In a recent study, an international team of researchers led by the University of Cologne made a startling discovery. Based on data collected by multiple observatories, they observed what appears to be a newly-formed star (X3a) in the vicinity of Sgr A*. This discovery raises significant questions about how young stellar objects (YSOs) can form and survive so close to an SMBH, where they should be torn apart by violent gravitational forces.

February 25, 2023February 25, 2023 by Matt Williams

Astronomers Suspected There Should Be a Planet Here, and Then They Took a Picture of it

Direct images of AF Lep b, acquired by the SPHERE instrument on the VLT. Credit: ESO/Paranal Observatory

To date, astronomers have confirmed 5,272 exoplanets in 3,943 systems using a variety of detection methods. Of these, 1,834 are Neptune-like, 1,636 are gas giants (Jupiter-sized or larger), 1,602 are rocky planets several times the size and mass of Earth (Super-Earths), and 195 have been Earth-like. With so many exoplanets available for study (and next-generation instruments optimized for the task), the process is shifting from discovery to characterization. And discoveries, which are happening regularly, are providing teasers of what astronomers will likely see in the near future.

For example, two international teams of astronomers independently discovered a gas giant several times the mass of Jupiter orbiting a Sun-like star about 87.5 light-years from Earth. In a series of new papers that appeared in Astronomy & Astrophysics, the teams report the detection of a Super-Jupiter orbiting AF Leporis (AF Lep b) using a combination of astrometry and direct imaging. The images they acquired using the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument (SPHERE) have since become the ESO’s Picture of the Week.

December 13, 2022December 13, 2022 by Matt Williams

Astronomers Spot Three Interacting Systems with Twin Discs

Artist's conceptualization of the dusty TYC 8241 2652 system as it might have appeared several years ago when it was emitting large amounts of excess infrared radiation. Credit: Gemini Observatory/AURA artwork by Lynette Cook. https://www.gemini.edu/node/11836

According to the most widely-accepted theory about star formation (Nebular Hypothesis), stars and planets form from huge clouds of dust and gas. These clouds undergo gravitational collapse at their center, leading to the birth of new stars, while the rest of the material forms disks around it. Over time, these disks become ring structures that accrete to form systems of planets, planetoids, asteroid belts, and Kuiper belts. For some time, astronomers have questioned how interactions between early stellar environments may affect their formation and evolution.

For instance, it has been theorized that gravitational interactions with a passing star or shock waves from a supernova might have triggered the core collapse that led to our Sun. To investigate this possibility, an international team of astronomers observed three interacting twin disc systems using the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) on the ESO’s Very Large Telescope (VLT). Their findings show that due to their dense stellar environments, gravitational encounters between early-stage star systems play a significant role in their evolution.

February 20, 2022February 20, 2022 by Andy Tomaswick

New Photos Show a Black Hole Blasting out Powerful Winds

Pictures of galaxies never cease to amaze, and astronomers are consistently coming up with new ones that provide a different viewpoint on the universe and maybe some exciting science along with it. A recent picture of the galaxy NGC 7582, taken with the Very Large Telescope (VLT), shows an active supermassive black hole at the galaxy’s core. However, something appears to be redirecting its “wind” away from the rest of the spiral galaxy.

February 18, 2022February 18, 2022 by Andy Tomaswick

An Asteroid has Been Discovered With Three Moons!

Planets aren’t the only celestial objects with moons – asteroids can have them too. They are usually other, smaller asteroids in orbit around a larger central one. Now, a team of Thai and French astronomers found an asteroid system with three satellites. The new four-body system makes complex gravitational problems like the three-body problem look simple by comparison.