A Star Became 1,000 Times Brighter, and Now Astronomers Know Why

Artist’s impression of one of the two stars in the FU Orionis binary system, surrounded by an accreting disk of material. What has caused this star — and others like it — to dramatically brighten? [NASA/JPL-Caltech]
Artist’s impression of one of the two stars in the FU Orionis binary system, surrounded by an accreting disk of material. Credit: NASA/JPL-Caltech

Astronomers were surprised in 1937 when a star in a binary pair suddenly brightened by 1,000 times. The pair is called FU Orionis (FU Ori), and it’s in the constellation Orion. The sudden and extreme variability of one of the stars has resisted a complete explanation, and since then, FU Orionis has become the name for other stars that exhibit similar powerful variability.

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Baby Stars Discharge “Sneezes” of Gas and Dust

The baby star at the center surrounded by a bright disk called a protostellar disk. Spikes of magnetic flux, gas, and dust in blue. Researchers found that the protostellar disk will expel magnetic flux, gas, and dust—much like a sneeze—during a star's formation.

I’m really not sure what to call it but a ‘dusty sneeze’ is probably as good as anything. We have known for some years that stars surround themselves with a disk of gas and dust known as the protostellar disk. The star interacts with it, occasionally discharging gas and dust regularly. Studying the magnetic fields revealed that they are weaker than expected. A new proposal suggests that the discharge mechanism ‘sneezes’ some of the magnetic flux out into space. Using ALMA, the team are hoping to understand the discharges and how they influence stellar formation. 

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Webb Joins the Hunt for Protoplanets

This artist’s impression shows the formation of a gas giant planet embedded in the disk of dust and gas in the ring of dust around a young star. A University of Michigan study aimed the James Webb Space Telescope at a protoplanetary disk surrounding a protostar called SAO 206462, hoping to find a gas giant planet in the act of forming. Image credit: ESO/L. Calçada

We can’t understand what we can’t clearly see. That fact plagues scientists who study how planets form. Planet formation happens inside a thick, obscuring disk of gas and dust. But when it comes to seeing through that dust to where nascent planets begin to take shape, astronomers have a powerful new tool: the James Webb Space Telescope.

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Betelgeuse’s Surface is Boiling Furiously

Simulation of Betelgeuse's boiling surface

Of all the stars in the sky, betelgeuse must be among the most enigmatic. One of its many mysteries surrounds the speed of its rotation which is surprisingly fast for a supergiant star. If it were placed where the Sun was, then its photosphere (visible layer) would be out around the orbit of Jupiter and it would be moving at 5 km/s. A new study now hints that instead of high rotation, it may be that the surface is boiling so furiously that it has been mistakingly identified as fast rotation. 

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This Planet-Forming Disk has More Water Than Earth’s Oceans

Astronomers have found water vapour in a disc around a young star exactly where planets may be forming. In this image, the new observations from the Atacama Large Millimeter/submillimeter Array (ALMA) show the water vapour in shades of blue. Image Credit: ALMA (ESO/NAOJ/NRAO)/S. Facchini et al.

Astronomers have detected a large amount of water vapour in the protoplanetary disk around a young star. There’s at least three times as much water among the dust as there is in all of Earth’s oceans combined. And it’s not spread throughout the disk; it’s concentrated in the inner disk region.

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A Protoplanetary Disc Has Been Found… in Another Galaxy!

With the combined capabilities of ESO’s Very Large Telescope (VLT) and the Atacama Large Millimeter/submillimeter Array (ALMA), a disc around a young massive star in another galaxy has been observed. The image at the centre shows the jets that accompany it. The top part of the jet is aimed slightly towards us and thus blueshifted; the bottom one is receding from us and thus redshifted. Observations from ALMA, right, then revealed the rotating disc around the star, similarly with sides moving towards and away from us. Credit: ESO/ALMA (ESO/NAOJ/NRAO)/A. McLeod et al.

Astronomers have imaged dozens of protoplanetary discs around Milky Way stars, seeing them at all stages of formation. Now, one of these discs has been found for the first time — excitingly — in another galaxy. The discovery was made using the Atacama Large Millimeter/Submillimeter Array (ALMA) in Chile along with the , which detected the telltale signature of a spinning disc around a massive star in the Large Magellanic Cloud, located 160,000 light-years away.

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A New Technique Has Dramatically Improved ALMA’s Resolution

Image showing two of the receivers of the ALMA array in the Atacama Desert.
Two of the Atacama Large Millimeter/submillimeter Array (ALMA) 12-metre antennas (Credit : Iztok Bon?ina/ESO)

To those familiar with optical telescopes, the idea of doing something to achieve higher resolution with their telescope may seem alien, if not, then practically impossible. A telescopes resolution is determined by among other things, its aperture – diameter of the thing that collects light (or electromagnetic radiation) and of course you can’t easily change that. Enter the team at ALMA, the Atacama Large Millimeter Array who have become the first to use the Band 10 receiver and extreme separation of the receivers to boosting its resolution so they can see detail equivalent of detecting a 10 meter long bus on the Moon!

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Strong Evidence that Supermassive Black Holes Affect Their Host Galaxy’s Chemistry

This is a composite image of the spiral galaxy Messier 77 (NGC 1068), as observed by ALMA and the Hubble Space Telescope. Red and blue are different chemicals. Red are cyanide radicals concentrated mostly in the center and a large-scale ring-shaped gas structure, but also along the bipolar jets extending from the center towards the northeast (upper left) and southwest (lower right). Blue is carbon monoxide isotopes which avoid the central region. Image Credit: ALMA (ESO/NAOJ/NRAO), NASA/ESA Hubble Space Telescope, T. Nakajima et al.

Supermassive Black Holes (SMBHs) are impossible to ignore. They can be billions of times more massive than the Sun, and when they’re actively consuming stars and gas, they become luminous active galactic nuclei (AGN.) A galaxy’s center is a busy place, with the activity centred on the SMBH.

New research provides strong evidence that while going about their business, SMBHs alter their host galaxy’s chemistry.

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Astronomers Find a Newly-Forming Quadruple-Star System

This artist’s impression shows the orbits of the objects in the HR 6819 triple system. Credit: ESO/L. Calçada

In a surprising find, the international ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP) team recently observed a young quadruple star system within a star-forming region in the Orion constellation. The discovery was made during a high-resolution survey of 72 dense cores in the Orion Giant Molecular Clouds (GMCs) using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. These observations provide a compelling explanation for the origins and formation mechanisms of binary and multiple-star systems.

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Is This The First Exoplanet Trojan, or the Result of an Epic Collision Between Worlds?

This image, taken with the Atacama Large Millimeter/submillimeter Array (ALMA), in which ESO is a partner, shows the young planetary system PDS 70, located nearly 400 light-years away from Earth. The system features a star at its centre, around which the planet PDS 70b (highlighted with a solid yellow circle) is orbiting. On the same orbit as PDS 70b, indicated by a solid yellow ellipse, astronomers have detected a cloud of debris (circled by a yellow dotted line) that could be the building blocks of a new planet or the remnants of one already formed. The ring-like structure that dominates the image is a circumstellar disc of material, out of which planets are forming. There is in fact another planet in this system: PDS 70c, seen at 3 o’clock right next to the inner rim of the disc.

It seems like every week, researchers are finding more and more interesting exoplanets. Many of them have analogs in our own solar system – hot Jupiter or Super Earth are commonly used as descriptions. However, there is a feature of a solar system that doesn’t exist in our solar system but might somewhere out in the galaxy – a Trojan planet. Now researchers from the Centro de Astrobiologia in Madrid and colleagues in the UK, EU, and US have found what they believe to be the first possible evidence of a Trojan planet.

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