Stellar Evolution Archives

February 20, 2023February 20, 2023 by Carolyn Collins Petersen

Some Elements Arrived on Earth by Surfing Supernova Shock Waves

Neutron-neutron star mergers are one way that heavy radioactive isotopes of elements found on Earth could be created. Courtesy ESO.

When stars die, they spread the elements they’ve created in their cores out to space. But, other objects and processes in space also create elements. Eventually, that “star stuff” scatters across the galaxy in giant debris clouds. Later on—sometimes millions of years later—it settles onto planets. What’s the missing link between element creation and deposition on some distant world?

December 13, 2022December 13, 2022 by Matt Williams

Astronomers Spot Three Interacting Systems with Twin Discs

Artist's conceptualization of the dusty TYC 8241 2652 system as it might have appeared several years ago when it was emitting large amounts of excess infrared radiation. Credit: Gemini Observatory/AURA artwork by Lynette Cook. https://www.gemini.edu/node/11836

According to the most widely-accepted theory about star formation (Nebular Hypothesis), stars and planets form from huge clouds of dust and gas. These clouds undergo gravitational collapse at their center, leading to the birth of new stars, while the rest of the material forms disks around it. Over time, these disks become ring structures that accrete to form systems of planets, planetoids, asteroid belts, and Kuiper belts. For some time, astronomers have questioned how interactions between early stellar environments may affect their formation and evolution.

For instance, it has been theorized that gravitational interactions with a passing star or shock waves from a supernova might have triggered the core collapse that led to our Sun. To investigate this possibility, an international team of astronomers observed three interacting twin disc systems using the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) on the ESO’s Very Large Telescope (VLT). Their findings show that due to their dense stellar environments, gravitational encounters between early-stage star systems play a significant role in their evolution.

November 17, 2022November 17, 2022 by Evan Gough

The Latest JWST Image Shows a Star in the Earliest Stage of Formation

The NASA/ESA/CSA James Webb Space Telescope has revealed the once-hidden features of the protostar within the dark cloud L1527 with its Near Infrared Camera (NIRCam), providing insight into the formation of a new star. These blazing clouds within the Taurus star-forming region are only visible in infrared light, making it an ideal target for Webb. Image Credit: NASA, ESA, CSA, and STScI, J. DePasquale (STScI), CC BY-SA 3.0 IGO

What’s the most exciting thing about the James Webb Space Telescope? The stunning images? The completion of its torturous path from concept to launch?

Or is it because it provides such compelling visual evidence of objects and processes long theorized about but difficult to observe?

November 9, 2022November 9, 2022 by Carolyn Collins Petersen

Hubble saw the Same Supernova at Three Different Times Thanks to Gravitational Lensing

As cosmic events go, supernova explosions epitomize the saying, “Live fast, die young, and leave a good-looking corpse.” They’re the deaths of stars so massive that they tear through their fuel in a short time. Then, they explode and create gorgeous scenes of stellar destruction. These seminal events enrich the universe with chemical elements for new generations of stars and planets.

November 5, 2022November 2, 2022 by Paul M. Sutter

It’s Tough to Find Evidence of Stars Eating Planets

Tragically sometimes stars engulf their own planets. While most stars are able to quickly cover up the evidence for their crime, a new study by astronomers has revealed that in some cases the evidence can linger for up to two billion years.

November 2, 2022November 2, 2022 by Paul M. Sutter

ESO Finds the Ghostly Image of a Dying Star

The Vela supernova remnant, as imaged by the VLT Survey Telescope, hosted at the European Southern Observatory’s (ESO’s) Paranal site in Chile.

Astronomical images never cease to delight, and the European Southern Observatory’s image of the Vela nebula is no exception.

October 25, 2022October 25, 2022 by Carolyn Collins Petersen

Hubble Looks at Newly Forming Stars in a Stellar Nursery

stellar nurseries and jets — The lives of newborn stars are tempestuous, as this image of the Herbig–Haro objects HH 1 and HH 2 from the NASA/ESA Hubble Space Telescope depicts.

When we look at images of star birth regions, they look both placid and active at the same time. That’s nowhere more true than in a stellar nursery associated with a so-called “Herbig-Haro” object. A recent image from Hubble Space Telescope zeroed in on two called “HH 1” and “HH 2”. It looked at the turbulence associated with a nearby newborn star system.

October 11, 2022October 11, 2022 by Evan Gough

Two Stars Orbiting Each Other Every 51 Minutes. This Can’t End Well

An artist’s illustration shows a white dwarf (right) circling a larger, sun-like star (left) in an ultra-short orbit, forming a “cataclysmic” binary system. Credits:Credit: M.Weiss/Center for Astrophysics | Harvard & Smithsonian

We don’t have to worry too much about our Sun. It can burn our skin, and it can emit potent doses of charged material—called Solar storms—that can damage electrical systems. But the Sun is alone up there, making things simpler and more predictable.

Other stars are locked in relationships with one another as binary pairs. A new study found a binary pair of stars that are so close to each other they orbit every 51 minutes, the shortest orbit ever seen in a binary system. Their proximity to one another spells trouble.

October 7, 2022October 7, 2022 by Evan Gough

Binary Stars Live Complicated Lives, Especially Near the End

Artist's impression of a red giant star. If the star is in a binary pair, what happens to its sibling? Credit:NASA/ Walt Feimer

We know what will happen to our Sun.

It’ll follow the same path other stars of its ilk follow. It’ll start running out of hydrogen, swell up and cool and turn red. It’ll be a red giant, and eventually, it’ll become so voluminous that it will consume the planets closest to it and render Earth uninhabitable. Then billions of years from now, it’ll create one of those beautiful nebulae we see in Hubble images, and the remnant Sun will be a shrunken white dwarf in the center of the nebula, a much smaller vestige of the luminous body it once was.

This is the predictable life the Sun lives as a solitary star. But what happens to stars that have a solar sibling? How would its binary companion fare?

September 9, 2022September 15, 2022 by Carolyn Collins Petersen

Just 2,000 Years Ago, Betelgeuse Was Yellow, Not Red

Artist's impression of Betelgeuse. Credit: ESO/L. Calçada

Compared to the lifespan of stars, human lives are pretty short. Stars such as Betelgeuse (in Orion) live for millions of years. Others exist for billions of years. We (if we’re lucky) get maybe 100 years (more or less). So, to us, stars don’t appear to change much over our lifetimes, unless they blow up as supernovae. But, what about over the course of 20 or 30 successive lifetimes?