Atacama Large Millimeter/submillimeter Array Archives

September 13, 2024September 13, 2024 by Matt Williams

More Bodies Discovered in the Outer Solar System

The Subaru Telescope at the Mauna Kea Observatories, Hawaii. Credit: NAOJ

The outer Solar System has been a treasure trove of discoveries in recent decades. Using ground-based telescopes, astronomers have identified eight large bodies since 2002 – Quouar, Sedna, Orcus, Haumea, Salacia, Eris, Makemake, and Gonggang. These discoveries led to the “Great Planet Debate” and the designation “dwarf planet,” an issue that remains contentious today. On December 21st, 2018, the New Horizons mission made history when it became the first spacecraft to rendezvous with a Kuiper Belt Object (KBO) named Arrokoth – the Powhatan/Algonquin word for “sky.”

Since 2006, the Subaru Telescope at the Mauna Kea Observatory in Hawaii has been observing the outer Solar System to search for other KBOs the New Horizons mission could study someday. In that time, these observations have led to the discovery of 263 KBOs within the traditionally accepted boundaries of the Kuiper Belt. However, in a recent study, an international team of astronomers identified 11 new KBOs beyond the edge of what was thought to be the outer boundary of the Kuiper Belt. This discovery has profound implications for our understanding of the structure and evolution of the Solar System.

September 8, 2024September 8, 2024 by Matt Williams

ALMA Detects Hallmark “Wiggle” of Gravitational Instability in Planet-Forming Disk

ALMA images reveal vast spiral arms in the AB Aurigae circumstellar disk (three rightmost panels), and counterparts observed with VLT/SPHERE (leftmost panel). Credit: ALMA (ESO/NAOJ/NSF NRAO), VLT/SPHERE (ESO), Speedie et al.

According to Nebula Theory, stars and their systems of planets form when a massive cloud of gas and dust (a nebula) undergoes gravitational collapse at the center, forming a new star. The remaining material from the nebula then forms a disk around the star from which planets, moons, and other bodies will eventually accrete (a protoplanetary disk). This is how Earth and the many bodies that make up the Solar System came together roughly 4.5 billion years ago, eventually settling into their current orbits (after a few migrations and collisions).

However, there is still debate regarding certain details of the planet formation process. On the one hand, there are those who subscribe to the traditional “bottom-up” model, where dust grains gradually collect into larger and larger conglomerations over tens of millions of years. Conversely, you have the “top-down” model, where circumstellar disk material in spiral arms fragments due to gravitational instability. Using the Atacama Large Millimeter/submillimeter Array (ALMA), an international team of astronomers found evidence of the “top-down” model when observing a protoplanetary disk over 500 light-years away.

June 20, 2024June 20, 2024 by Matt Williams

Matched Twin Stars are Firing Their Jets Into Space Together

This artist’s concept shows two young stars nearing the end of their formation. Encircling the stars are disks of leftover gas and dust from which planets may form. Jets of gas shoot away from the stars’ north and south poles. Credit: NASA

Since it began operating in 2022, the James Webb Space Telescope (JWST) has revealed some surprising things about the Universe. The latest came when a team of researchers used Webb‘s Mid-Infrared Instrument (MIRI) to observe Rho Ophiuchi, the closest star-forming nebula to Earth, about 400 light-years away. While at least five telescopes have studied the region since the 1970s, Webb’s unprecedented resolution and specialized instruments revealed what was happening at the heart of this nebula.

For starters, while observing what was thought to be a single star (WL 20S), the team realized they were observing a pair of young stars that formed 2 to 4 million years ago. The MIRI data also revealed that the twin stars have matching jets of hot gas (aka stellar jets) emanating from their north and south poles into space. The discovery was presented at the 244th meeting of the American Astronomical Society (224 AAS) on June 12th. Thanks to additional observations made by the Atacama Large Millimeter/submillimeter Array (ALMA), the team was surprised to notice large clouds of dust and gas encircling both stars.

July 19, 2023July 19, 2023 by Matt Williams

Star Birth and Death Seen Near the Beginning of Time

An artist's illustration of the Universe's first stars, called Population 3 stars. Pop 3 stars would have been much more massive than most stars today, and would have burned hot and blue. Their lifetimes would've been much shorter than stars like our Sun. Credit: Wikimedia Commons

Until recently, astronomers could not observe the first stars and galaxies that formed in the Universe. This occurred during what is known as the “Cosmic Dark Ages,” a period that took place between 380,000 and 1 billion years after the Big Bang. Thanks to next-generation instruments like the James Webb Space Telescope (JWST), improved methods and software, and updates to existing observatories, astronomers are finally piercing the veil of this era and getting a look at how the Universe as we know it began.

This includes new observations from the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, which obtained images of a stellar nursery inside a galaxy roughly 13.2 billion light-years away in the constellation Eridanus. This galaxy has a redshift value of more than 8.3, corresponding to when the Universe was less than 1 billion years old. The images discerned the sites of star formation and possible star death inside a nebula (MACS0416_Y1) located within this galaxy. This represents a major milestone for astronomy as this is the farthest distance such structures have been observed in our Universe.

March 7, 2023March 7, 2023 by Matt Williams

A Tadpole-Shaped Cloud of Gas is Whirling Around a Black Hole

Artist’s Impression of the “Tadpole” Molecular Cloud and the black hole at the gravitational center of its orbit. Credit: Keio University

In the 1930s, astrophysicists theorized that at the end of their life cycle, particularly massive stars would collapse, leaving behind remnants of infinite mass and density. As a proposed resolution to Einstein’s field equations (for his Theory of General Relativity), these objects came to be known as “black holes” because nothing (even light) could escape them. By the 1960s, astronomers began to infer the existence of these objects based on the observable effects they have on neighboring objects and their surrounding environment.

Despite improvements in instruments and interferometry (which led to the first images of M87 and Sagittarius A*), the study of black holes still relies on indirect methods. In a recent study, a team of Japanese researchers identified an unusual cloud of gas that appears to have been elongated by a massive, compact object that it orbits. Since there are no massive stars in its vicinity, they theorize that the cloud (nicknamed the “Tadpole” because of its shape) orbits a black hole roughly 27,000 light-years away in the constellation Sagittarius.

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 10, 2023February 10, 2023 by Matt Williams

Machine Learning is a Powerful Tool When Searching for Exoplanets

Three young planets in orbit around an infant star known as HD 163296 Credit: NRAO/AUI/NSF; S. Dagnello

Astronomy has entered the era of big data, where astronomers find themselves inundated with information thanks to cutting-edge instruments and data-sharing techniques. Facilities like the Vera Rubin Observatory (VRO) are collecting about 20 terabytes (TB) of data on a daily basis. Others, like the Thirty-Meter Telescope (TMT), are expected to gather up to 90 TB once operational. As a result, astronomers are dealing with 100 to 200 Petabytes of data every year, and astronomy is expected to reach the “exabyte era” before long.

In response, observatories have been crowdsourcing solutions and making their data open-access so citizen scientists can assist with the time-consuming analysis process. In addition, astronomers have been increasingly turning to machine learning algorithms to help them identify objects of interest (OI) in the Universe. In a recent study, a team led by the University of Georgia revealed how artificial intelligence could distinguish between false positives and exoplanet candidates simultaneously, making the job of exoplanet hunters that much easier.

June 15, 2021June 15, 2021 by Andy Tomaswick

Rare Triple Galaxy Merger With at Least Two Supermassive Black Holes

One of the best things about that universe is that there is so much to it. If you look hard enough, you can most likely find any combination of astronomical events happening. Not long ago we reported on research that found 7 separate instances of three galaxies colliding with one another. Now, a team led by Jonathan Williams of the University of Maryland has found another triple galaxy merging cluster, but this one might potentially have two active supermassive black holes, allowing astronomers to peer into the system dynamics of two of the universe’s most extreme objects running into one another.

November 6, 2020November 6, 2020 by Matt Williams

Titan’s Atmosphere Has All the Ingredients For Life. But Not Life as We Know It

A global mosaic of the surface of Titan, thanks to the infrared eyes of the Cassini spacecraft. Image Credit: NASA/JPL-Caltech/University of Nantes/University of Arizona

Using the Atacama Large Millimeter/submillimeter Array (ALMA), a team of scientists has identified a mysterious molecule in Titan’s atmosphere. It’s called cyclopropenylidene (C₃H₂), a simple carbon-based compound that has never been seen in an atmosphere before. According to the team’s study published in The Astronomical Journal, this molecule could be a precursor to more complex compounds that could indicate possible life on Titan.

Similarly, Dr. Catherine Neish of the University of Western Ontario’s Institute for Earth and Space Exploration (Western Space) and her colleagues in the European Space Agency (ESA) found that Titan has other chemicals that could be the ingredients for exotic life forms. In their study, which appeared in Astronomy & Astrophysics, they present Cassini mission data that revealed the composition of impact craters on Titan’s surface.

August 18, 2020August 18, 2020 by Matt Williams

This Distorted Circle is Actually a Galaxy That Looked Very Similar to the Milky Way, Shortly After the Big Bang

Astronomers using ALMA, in which the ESO is a partner, have revealed an extremely distant galaxy that looks surprisingly like our Milky Way. The galaxy, SPT0418-47, is gravitationally lensed by a nearby galaxy, appearing in the sky as a near-perfect ring of light.

The most widely accepted cosmological view states that the first galaxies formed about 380–400 million years after the Big Bang. These were made up of young, hot stars that lived fast and died young, causing the galaxies themselves to be turbulent. At least, that was the theory until a European team of astronomers observed a galaxy 12 billion light-years away that closely resembled the Milky Way.

Using the Atacama Large Millimeter-submillimeter Array (ALMA), the team observed the galaxy, SPT0418-47, as it appeared when the Universe was just 1.4 billion years old. Much to their surprise, the team noted that the structure and features of this galaxy were highly evolved and stable, something that contradicts previously-held notions about the nature of galaxies in the early Universe.