Stellar Evolution Archives

November 27, 2023November 27, 2023 by Evan Gough

Vampire Stars Get Help from a Third Star to Feed

Artist’s impression composed of a star with a disc around it (a Be “vampire” star; foreground) and its companion star that has been stripped of its outer parts (background). Credit: ESO/L. Calçada

Some stars are stuck in bad binary relationships. A massive primary star feeds on its smaller companion, sucking gas from the companion and adding it to its own mass while diminishing its unfortunate partner. These vampire stars are called Be stars, and up until now, astronomers thought they existed in binary relationships.

But new research shows that these stars are only able to feed on their diminutive neighbour because of a third star present in the system.

November 17, 2023November 17, 2023 by Evan Gough

Can a Dead Star Keep Exploding?

This is an artist’s representation of AT2022tsd, an explosion in a distant galaxy. The image shows one possible explanation for the strange object. It could be a black hole accreting matter from a disk and powering a jet. Variation in the jet's direction could produce the observed rapid flashes. Image Credit: Robert L. Hurt/Caltech/IPAC

In September 2022, an automated sky survey detected what seemed to be a supernova explosion about one billion light-years away. The Zwicky Transient Facility (ZTF) spotted it and gave it the name AT2022tsd. But something was different about this supernova. Supernovae explode and shine brightly for months, while AT2022tsd exploded brightly and then faded within days.

October 5, 2023October 5, 2023 by Carolyn Collins Petersen

A Star Threw Off a Sun’s Worth of Material. And Then it Exploded!

Artist's conception of SN 2023ixf. One of the nearest Type II supernovae in a decade and among the brightest to date, SN 2023ixf is a young supernova. Its progenitor star exploded and the supernova was discovered earlier this year by amateur astronomer K?ichi Itagaki of Yamagata, Japan. Credit: Melissa Weiss/CfA

What happens just before a massive star explodes as a supernova? To figure that out, astronomers need to look at very “young” supernovae across multiple wavelengths of light. That’s what happened when SN 2023ixf occurred in May 2023. It turns out its aging progenitor star blew off a solar mass worth of material just before it died. Now, the big question is: why?

August 22, 2023August 22, 2023 by Brian Koberlein

When the Sun Dies, it Could Produce a Fantastic Ring in Space, Like This New Image From JWST

The Ring Nebula seen by JWST's Near-Infrared Camera (left) and Mid-Infrared Instrument (right). Credit: ESA/Webb, NASA, CSA, M. Barlow (University College London), N. Cox (ACRI-ST), R. Wesson (Cardiff University)

Planetary nebulae were first discovered in the 1700s. Legend tells us that through the small telescopes of the time, they looked rather planet-like, hence the name. Real history is a bit more fuzzy, and early objects categorized as planetary nebulae included things such as galaxies. But the term stuck when applied to circular emission nebulae centered around a dying star. As new observations show, planetary nebulae have a structure that is both simple and complex.

August 20, 2023August 20, 2023 by Carolyn Collins Petersen

Is This How You Get Magnetars?

An artist's impression of the star HD 4 5166, which is on its way to becoming a magnetar. Courtesy ESO.

Imagine a living star with a magnetic field at least 100,000 times stronger than Earth’s field. That’s the strange stellar object HD 45166. Its field is an incredible 43,000 Gauss. That makes it a new type of object: a massive magnetic helium star. In a million years, it’s going to get even stranger when it collapses and becomes a type of neutron star called a “magnetar”.

August 18, 2023August 18, 2023 by Brian Koberlein

A New Simulation Reveals One Entire Stage of a Star's Life

The interior structure of our Sun. Credit: Kelvin Ma, via Wikipedia

Nuclear fusion is at the center of stellar evolution. Most of a star’s life is a battle between gravity and nuclear power. While we understand this process on a broad scale, many of the details still elude us. We can’t dive into a star to see its nuclear furnace, so we rely on complex computer simulations. A recent study has made a big step forward by modeling the entire fusion cycle of a single element.

August 4, 2023August 4, 2023 by Carolyn Collins Petersen

Yes! A JWST Image of the Ring Nebula

JWST/NIRcam composite image of the Ring Nebula. The images clearly show the main ring, surrounded by a faint halo and with many delicate structures. The interior of the ring is filled with hot gas. The star which ejected all this material is visible at the very center. Courtesy JWST/University of Manchester.

Brace yourselves for great JWST views of the iconic Ring Nebula (M57). An international team of astronomers just released a fantastic near-infrared image of the nebula, showing incredible details.

July 29, 2023July 29, 2023 by Carolyn Collins Petersen

Astronomers are Watching a Planet Get its Atmosphere Blasted Away into Space

This artist's illustration shows a planet (dark silhouette) passing in front of the red dwarf star AU Microscopii. The planet is so close to the eruptive star a ferocious blast of stellar wind and blistering ultraviolet radiation is heating the planet's hydrogen atmosphere, causing it to escape into space. The illustration is based on measurements made by the Hubble Space Telescope. Credits: NASA, ESA, and Joseph Olmsted (STScI)

What do you get when a hot young world orbits a wildly unstable young red dwarf? For AU Microsopii b, the answer is: flares from the star tearing away the atmosphere. That catastrophic loss happens in fits and starts, “hiccuping” out its atmosphere at one point and then losing practically none the next.

July 25, 2023July 25, 2023 by Brian Koberlein

Astronomers Have a New Trick to Work out the Age of Stars

A frame from the Kepler Telescope showing a couple binary systems. Credit: AIP/ David Gruner, NASA (Kepler FFI) & ESO (zoomed)

Twinkle, twinkle little star, I wonder just how old you are.

It isn’t an easy question to answer. Stars are notoriously difficult to age. We know the age of the Sun because we happen to live on one of its orbiting rocks, and we know very well how old the rock is. Without that information, things become a bit more fuzzy. But that could change thanks to a new study.

July 21, 2023July 21, 2023 by Carolyn Collins Petersen

Record-Breaking Magnetar was There in the Data All Along

An artist’s impression of the ultra-long period magnetar—a rare type of star with extremely strong magnetic fields that can produce powerful bursts of energy. Credit: ICRAR

The cosmic zoo has strange beasts that astronomers stumble across in the most fascinating ways. Not long ago a team in Australia found a highly unusual magnetar, one of the weirder denizens of the starry zoo. It’s called GPM J1839-10 and it lies some 15,000 light-years away in the direction of the constellation Scutum.