Quite Dramatic End to a Planet Swallowed by its Host Star

An artist's concept shows a ring of hot gas left after a star consumed a planet, in this undated illustration. NASA, ESA, CSA, Ralf Crawford (STScI)/Handout via REUTERS
An artist's concept shows a ring of hot gas left after a star consumed a planet, in this undated illustration. NASA, ESA, CSA, Ralf Crawford (STScI)/Handout via REUTERS
TT
20

Quite Dramatic End to a Planet Swallowed by its Host Star

An artist's concept shows a ring of hot gas left after a star consumed a planet, in this undated illustration. NASA, ESA, CSA, Ralf Crawford (STScI)/Handout via REUTERS
An artist's concept shows a ring of hot gas left after a star consumed a planet, in this undated illustration. NASA, ESA, CSA, Ralf Crawford (STScI)/Handout via REUTERS

In May 2020, astronomers for the first time observed a planet getting swallowed by its host star. Based on the data at the time, they believed the planet met its doom as the star puffed up late in its lifespan, becoming what is called a red giant.

New observations by the James Webb Space Telescope - sort of a postmortem examination - indicate that the planet's demise happened differently than initially thought, according to Reuters.

Instead of the star coming to the planet, it appears the planet came to the star, with disastrous consequences – a death plunge after an erosion of this alien world's orbit over time, researchers said.

The end was quite dramatic, as evidenced by the aftermath documented by Webb.

Reuters wrote that the orbiting telescope, which was launched in 2021 and became operational in 2022, observed hot gas likely forming a ring around the star following the event and an expanding cloud of cooler dust enveloping the scene.

“We do know that there is a good amount of material from the star that gets expelled as the planet goes through its death plunge. The after-the-fact evidence is this dusty leftover material that was ejected from the host star,” said astronomer Ryan Lau of the US National Science Foundation's NOIRLab, lead author of the study published in the Astrophysical Journal.

The star is located in our Milky Way galaxy about 12,000 light-years from Earth in the direction of the constellation Aquila.

A light year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km). The star is slightly redder and less luminous than our sun and about 70% of its mass.

The planet is believed to have been from a class called “hot Jupiter’s” - gas giants at high temperatures owing to a tight orbit around their host star.

“We believe it probably had to be a giant planet, at least a few times the mass of Jupiter, to cause as dramatic of a disturbance to the star as what we are seeing,” said study co-author Morgan MacLeod, a postdoctoral fellow at the Harvard-Smithsonian Center for Astrophysics.

Jupiter is our solar system's largest planet.

The researchers believe that the planet's orbit had gradually deteriorated due to its gravitational interaction with the star, and hypothesized about what happened next.

“Then it starts grazing through the atmosphere of the star. At that point, the headwind of smashing through the stellar atmosphere takes over and the planet falls increasingly rapidly into the star,” MacLeod said.

“The planet both falls inward and gets stripped of its gaseous outer layers as it plows deeper into the star. Along the way, that smashing heats up and expels stellar gas, which gives rise to the light we see and the gas, dust and molecules that now surround the star,” MacLeod said.

But they cannot be certain of the actual fatal events.

“In this case, we saw how the plunge of the planet affected the star, but we don't truly know for certain what happened to the planet. In astronomy there are lots of things way too big and way too 'out there' to do experiments on. We can't go to the lab and smash a star and planet together - that would be diabolical. But we can try to reconstruct what happened in computer models,” MacLeod said.

None of our solar system's planets are close enough to the sun for their orbits to decay, as happened here. That does not mean that the sun will not eventually swallow any of them.

About five billion years from now, the sun is expected to expand outward in its red giant phase and could well engulf the innermost planets Mercury and Venus, and maybe even Earth. During this phase, a star blows off its outer layers, leaving just a core behind - a stellar remnant called a white dwarf.

Webb's new observations are giving clues about the planetary endgame.

“Our observations hint that maybe planets are more likely to meet their final fates by slowly spiraling in towards their host star instead of the star turning into a red giant to swallow them up. Our solar system seems to be relatively stable though, so we only have to worry about the sun becoming a red giant and swallowing us up,” Lau said.



New T-Rex Ancestor Discovered in Drawers of Mongolian Institute

A life reconstruction of the newly identified dinosaur species Khankhuuluu mongoliensis, which lived 86 million years ago in Mongolia, is seen in this handout illustration released on June 11, 2025. (Julius Csotonyi/Handout via Reuters)
A life reconstruction of the newly identified dinosaur species Khankhuuluu mongoliensis, which lived 86 million years ago in Mongolia, is seen in this handout illustration released on June 11, 2025. (Julius Csotonyi/Handout via Reuters)
TT
20

New T-Rex Ancestor Discovered in Drawers of Mongolian Institute

A life reconstruction of the newly identified dinosaur species Khankhuuluu mongoliensis, which lived 86 million years ago in Mongolia, is seen in this handout illustration released on June 11, 2025. (Julius Csotonyi/Handout via Reuters)
A life reconstruction of the newly identified dinosaur species Khankhuuluu mongoliensis, which lived 86 million years ago in Mongolia, is seen in this handout illustration released on June 11, 2025. (Julius Csotonyi/Handout via Reuters)

Misidentified bones that languished in the drawers of a Mongolian institute for 50 years belong to a new species of tyrannosaur that rewrites the family history of the mighty T-Rex, scientists said Wednesday.

This slender ancestor of the massive Tyrannosaurus Rex was around four meters (13 feet) long and weighed three quarters of a ton, according to a new study in the journal Nature.

"It would have been the size of a very large horse," study co-author Darla Zelenitsky of Canada's University of Calgary told AFP.

The fossils were first dug up in southeastern Mongolia in the early 1970s, but at the time were identified as belonging to a different tyrannosaur, Alectrosaurus.

For half a century, the fossils sat in the drawers at the Institute of Paleontology of the Mongolian Academy of Sciences in the capital Ulaanbaatar.

Then PhD student Jared Voris, who was on a trip to Mongolia, started looking through the drawers and noticed something was wrong, Zelenitsky said.

It turned out the fossils were well-preserved, partial skeletons of two different individuals of a completely new species.

"It is quite possible that discoveries like this are sitting in other museums that just have not been recognized," Zelenitsky added.

They named the new species Khankhuuluu mongoliensis, which roughly means the dragon prince of Mongolia because it is smaller than the "king" T-Rex.

Zelenitsky said the discovery "helped us clarify a lot about the family history of the tyrannosaur group because it was really messy previously".

The T-Rex represented the end of the family line.

It was the apex predator in North America until 66 million years ago, when an asteroid bigger than Mount Everest slammed into the Gulf of Mexico.

Three quarters of life on Earth was wiped out, including all the dinosaurs that did not evolve into birds.

Around 20 million years earlier, Khankhuuluu -- or another closely related family member -- is now believed to have migrated from Asia to North America using the land bridge that once connected Siberia and Alaska.

This led to tyrannosaurs evolving across North America.

Then one of these species is thought to have crossed back over to Asia, where two tyrannosaur subgroups emerged.

One was much smaller, weighing under a ton, and was nicknamed Pinocchio rex for its long snout.

The other subgroup was huge and included behemoths like the Tarbosaurus, which was only a little smaller than the T-rex.

One of the gigantic dinosaurs then left Asia again for North America, eventually giving rise to the T-Rex, which dominated for just two million years until the asteroid struck.