Binary Dwarf Stars Found Orbiting Each Other Every 20 Hours. They Were Once Almost Touching

Astronomers have spotted a pair of ultra-cool dwarf stars in a tight binary configuration. They rotate around one another in less than one Earth day. Image Credit: NASA/JPL Caltech

A team of astrophysicists has discovered a binary pair of ultra-cool dwarfs so close together that they look like a single star. They’re remarkable because they only take 20.5 hours to orbit each other, meaning their year is less than one Earth Day. They’re also much older than similar systems.

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The Donut That Used To Be a Star

This sequence of artist's illustrations shows how a black hole can devour a bypassing star. 1) A normal star passes near a supermassive black hole in the center of a galaxy. 2) The star's outer gasses are pulled into the black hole's gravitational field. 3) The star is shredded as tidal forces pull it apart. 4) The stellar remnants are pulled into a donut-shaped ring around the black hole, and will eventually fall into the black hole, unleashing a tremendous amount of light and high-energy radiation. Credit: NASA, ESA, Leah Hustak (STScI)

The death of a star is one of the most dramatic natural events in the Universe. Some stars die in dramatic supernova explosions, leaving nebulae behind as shimmering remnants of their former splendour. Some simply wither away as their hydrogen runs out, billowing into a red giant as they do so.

But others are consumed by behemoth black holes, and as they’re destroyed, the black hole’s powerful gravity tears the star apart and draws its gas into a donut-shaped ring around the black hole.

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A Black Hole Consumed a Star and Released the Light of a Trillion Suns

A star is being consumed by a distant supermassive black hole. Astronomers call this a tidal disruption event (TDE). As the black hole rips apart the star, two jets of material moving with almost the speed of light are launched in opposite directions. One of the jets was aimed directly at Earth. Image credit: Carl Knox (OzGrav, ARC Centre of Excellence for Gravitational Wave Discovery, Swinburne University of Technology)

When a flash of light appears somewhere in the sky, astronomers notice. When it appears in a region of the sky not known to host a stellar object that’s flashed before, they really sit up and take notice. In astronomical parlance, objects that emit flashing light are called transients.

Earlier this year, astronomers spotted a transient that flashed with the light of a trillion Suns.

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Planets Make it Harder to Figure out a Star’s age

Active star, nearby exoplanet, and inactive companion star for NASA's Chandra X-ray Observatory. 2022

Estimating stellar age has always been a challenge for astronomers. Now, a certain class of exoplanets is making the process even more complicated. Hot Jupiters – gas giants with orbital periods smaller than that of Mercury – appear to have an anti-aging effect on their stars, according to a new study. These enormous planets inflict both magnetic and tidal interference on their host star, speeding up the star’s rotation and causing them to emit X-rays more energetically, both of which are hallmarks of stellar youth. The result calls into question some of what we previously believed about stellar age, and offers a glimpse at the ongoing interconnectivity between a star and its planets long after their formation.

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Another Reason Red Dwarfs Might Be Bad for Life: No Asteroid Belts

In a recent study accepted to The Astrophysical Journal Letters, a team of researchers at the University of Nevada, Las Vegas (UNLV) investigated the potential for life on exoplanets orbiting M-dwarf stars, also known as red dwarfs, which are both smaller and cooler than our own Sun and is currently open for debate for their potential for life on their orbiting planetary bodies. The study examines how a lack of an asteroid belt might indicate a less likelihood for life on terrestrial worlds.

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Astronomers Find a Star That Contains 65 Different Elements

This is an image of M80, an ancient globular cluster of stars. Since these stars formed in the early universe, their metallicity content is very low. This means that gas giants like Jupiter would be rare or non-existent here, while brown dwarfs are likely plentiful. Image: By NASA, The Hubble Heritage Team, STScI, AURA - Great Images in NASA Description, Public Domain, https://commons.wikimedia.org/w/index.php?curid=6449278
This is an image of M80, an ancient globular cluster of stars. Since these stars formed in the early universe, their metallicity content is very low. This means that gas giants like Jupiter would be rare or non-existent here, while brown dwarfs are likely plentiful. Image: By NASA, The Hubble Heritage Team, STScI, AURA - Great Images in NASA Description, Public Domain, https://commons.wikimedia.org/w/index.php?curid=6449278

Have you ever held a chunk of gold in your hand? Not a little piece of jewelry, but an ounce or more? If you have, you can almost immediately understand what drives humans to want to possess it and know where it comes from.

We know that gold comes from stars. All stars are comprised primarily of hydrogen and helium. But they contain other elements, which astrophysicists refer to as a star’s metallicity. Our Sun has a high metallicity and contains 67 different elements, including about 2.5 trillion tons of gold.

Now astronomers have found a distant star that contains 65 elements, the most ever detected in another star. Gold is among them.

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TESS Finds Almost 100 Quadruple Star Systems

This is an artist's illustration of the quadruple star system 30 Arietis. Astronomers are discovering more quadruple star systems as observational power increases. Image Credit: Karen Teramura, UH IfA

NASA’s Transiting Exoplanet Survey Satellite (TESS) has found over 5000 candidate exoplanet candidates, and 197 confirmed exoplanets since its mission began in late 2018. TESS is good at finding exoplanets, but the spacecraft is a powerful scientific platform, and it’s made other discoveries, too. Scientists working with TESS recently announced 97 quadruple star candidates, nearly doubling the number of known quadruple systems.

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Planet Found in the Habitable Zone of a White Dwarf

An artist’s impression of the white dwarf star WD1054–226 orbited by clouds of planetary debris and a major planet in the habitable zone. Credit Mark A. Garlick / markgarlick.com Licence type Attribution (CC BY 4.0)

Most stars will end their lives as white dwarfs. White dwarfs are the remnant cores of once-luminous stars like our Sun, but they’ve left their lives of fusion behind and no longer generate heat. They’re destined to glow with only their residual energy for billions of years before they eventually fade to black.

Could life eke out an existence on a planet huddled up to one of these fading spectres?

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A Second Generation of Planets can Form Around a Dying Star

An illustration of a protoplanetary disk. Planets coalesce out of the remaining molecular cloud the star formed out of. Within this accretion disk lay the fundamental elements necessary for planet formation and potential life. Credit: NASA/JPL-Caltech/T. Pyle (SSC) - February, 2005
An illustration of a protoplanetary disk. Planets coalesce out of the remaining molecular cloud the star formed out of. Within this accretion disk lay the fundamental elements necessary for planet formation and potential life. Credit: NASA/JPL-Caltech/T. Pyle (SSC) - February, 2005

When young stars coalesce out of a cloud of molecular hydrogen, a disk of leftover material called a protoplanetary disk surrounds them. This disk is where planets form, and astronomers are getting better at peering into those veiled environments and watching embryonic worlds take shape. But young stars aren’t the only stars with disks of raw material rotating around them.

Some old, dying stars also have disks. Can a second generation of planets form under those conditions?

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Latest Hubble Image Shows the Star-Forming Chamaeleon Cloud

This is a Hubble composite image of the Chamaeleon I cloud complex. Image Credit: NASA, ESA, K. Luhman and T. Esplin (Pennsylvania State University), et al., and ESO; Processing: Gladys Kober (NASA/Catholic University of America)

Stars form inside vast collections of molecular hydrogen called molecular clouds, sometimes called stellar nurseries or star forming regions. Instabilities in the clouds cause gas to collapse in on itself, and when enough material gathers and the density reaches a critical stage, a star begins its life of fusion.

But molecular clouds aren’t always alone. They often exist in association with other clouds, and astronomers call these formations Cloud Complexes. The Chamaeleon Cloud Complex (CCC) is one of the closest active star forming regions to Earth. It’s further divided into three substructures called dark clouds, or dark nebula. They are Chamaeleon 1 (Cha1), Chamaeleon 2, and Chamaeleon 3.

NASA created a new composite image of Chamaeleon 1 based on Hubble images, and the vivid panorama brings Chamaeleon I to life.

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