Merging Galaxies Make for Explosive Star Formation

A festive array of bright pinks and blues makes for a remarkable sight in this image captured with the Gemini North telescope, one half of the International Gemini Observatory. Resembling a cloud of cosmic confetti, this image is being released in celebration of Gemini North’s 25th anniversary. NGC 4449 is a prime example of starburst activity caused by the interacting and mingling of galaxies as it slowly absorbs its smaller galactic neighbors.

The Gemini Observatory has unveiled a striking new image that shows star formation within the irregular galaxy NGC 4449. This galaxy is categorised as a “Magellanic-type” galaxy due to its similarities  with the Magellanic Clouds, although it is smaller in size. Surrounding NGC 4449 is a halo of smaller dwarf galaxies, two of which are currently merging with it. This merger is causing clouds of gas to collide, fuelling the surge in star formation observed in NGC 4449.

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The JWST Peers into the Heart of Star Formation

In this image of the Serpens Nebula from the Near-InfraRed Camera (NIRCam) on the NASA/ESA/CSA James Webb Space Telescope, astronomers found a grouping of aligned protostellar outflows within one small region (the top left corner). In the Webb image, these jets are identified by bright red clumpy streaks, which are shockwaves caused when the jet hits the surrounding gas and dust. Image Credit: NASA, ESA, CSA, STScI, K. Pontoppidan (NASA’s Jet Propulsion Laboratory), J. Green (Space Telescope Science Institute)

The James Webb Space Telescope has unlocked another achievement. This time, the dynamic telescope has peered into the heart of a nearby star-forming region and imaged something astronomers have longed to see: aligned bipolar jets.

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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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Binary Stars Form in the Same Nebula But Aren’t Identical. Now We Know Why.

This artist’s impression illustrates a binary pair of giant stars. Despite being born from the same molecular cloud, astronomers often detect differences in binary stars’ chemical compositions and planetary systems. Image Credit: NOIRLab/NSF/AURA/J. da Silva (Spaceengine)/M. Zamani

It stands to reason that stars formed from the same cloud of material will have the same metallicity. That fact underpins some avenues of astronomical research, like the search for the Sun’s siblings. But for some binary stars, it’s not always true. Their composition can be different despite forming from the same reservoir of material, and the difference extends to their planetary systems.

New research shows that the differences can be traced back to their earliest stages of formation.

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Another New Molecule Discovered Forming in Space

New research has revealed the presence of a previously unknown molecule in space called 2-methoxyethanol. Scientists found the large, 13-atom molecule in the star forming region NGC 63341. Image Credit: Fried et al. 2924.

The list of chemicals found in space is growing longer and longer. Astronomers have found amino acids and other building blocks of life on comets, asteroids, and even floating freely in space. Now, researchers have found another complex chemical to add to the list.

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Hubble Sees a Star About to Ignite

The FS Tau multi-star system. Credit: NASA, ESA, K. Stapelfeldt (NASA JPL), G. Kober (NASA/Catholic University of America)

We know how stars form. Clouds of interstellar gas and dust gravitationally collapse to form a burst of star formation we call a stellar nursery. Eventually, the cores of these protostars become dense enough to ignite their nuclear furnace and shine as true stars. But catching stars in that birth-moment act is difficult. Young stars are often hidden deep within their dense progenitor cloud, so we don’t see their light until they’ve already started shining. But new observations from the Hubble Space Telescope have given us our earliest glimpse of a shiny new star.

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Webb Sees a Star-Forming Region Blowing Vast Bubbles

JWST's near-infrared view of the star-forming region NGC 604 in the Triangulum galaxy. Credit: NASA, ESA, CSA, STScI
JWST's near-infrared view of the star-forming region NGC 604 in the Triangulum galaxy. Credit: NASA, ESA, CSA, STScI

Star birth is a messy and chaotic event. Some of the process remains well hidden behind clouds of gas and dust that make up star-forming regions. However, part of it happens in wavelengths of light we can detect, such as visible light and infrared. It’s an intricate process that the Webb telescope (JWST) can study in detail.

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This Galaxy Was Already Dead When the Universe Was Only 700 Million Years Old

False-color JWST image of a small fraction of the GOODS South field, with the galaxy JADES-GS-z7-01-QU highlighted Credit: JADES Collaboration
False-color JWST image of a small fraction of the GOODS South field, with the galaxy JADES-GS-z7-01-QU highlighted Credit: JADES Collaboration

When a galaxy runs out of gas and dust, the process of star birth stops. That takes billions of years. But, there’s a galaxy out there that was already dead when the Universe was only 700 million years old. What happened to it?

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Even Stars Like the Sun Can Unleash Savage Flares in Their Youth

Artist's concept of the flare that burst out from the young nearby star HD 283572. The flare was detected by the Submillimeter Array on Mauna Kea, in Hawai'i. Credit: CfA/Melissa Weiss.
Artist's concept of the flare that burst out from the young nearby star HD 283572. The flare was detected by the Submillimeter Array on Mauna Kea, in Hawai'i. Credit: CfA/Melissa Weiss.

Why would a young Sun-like star suddenly belch out a hugely bright flare? That’s what astronomers at Harvard Smithsonian Astrophysical Observatory want to know after they spotted such an outburst using a sensitive submillimeter-wave telescope. According to Joshua Bennett Lovell, leader of a team that observed the star’s activity, these kinds of flare events are rare in such young stars, particularly at millimeter wavelengths. So, what’s happening there?

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The JWST Discovers a Galaxy That Shouldn’t Exist

The JWST captured this image of an unusual quiescent dwarf galaxy in the background of separate observations. Image Credit: Carleton et al. 2024

Astronomers working with the JWST found a dwarf galaxy they weren’t looking for. It’s about 98 million years away, has no neighbours, and was in the background of an image of other galaxies. This isolated galaxy shows a lack of star-formation activity, which is very unusual for an isolated dwarf.

Most isolated dwarf galaxies form stars, according to a wealth of observations. What’s different about this one?

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