Study Findings: The Barnard’s Star Planetary System: Stability, Composition, and Evolution of Four Sub-Earth Exoplanets

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Credit: NASA Photojournal

Monthly Notices of the Royal Astronomical Society abstract of study findings:

Barnard’s Star is the nearest single star to the Sun (1.8 pc⁠⁠), and hosts four recently discovered planets. The star also has well-characterized stellar abundances of important rock-forming elements, including Fe, Mg, and Si. For refractory elements like these, the planets have likely inherited similar bulk elemental abundance ratios to the star, facilitating modelling of their interior structures. We present here an analysis of the Barnard’s Star planetary system on several fronts. We perform a detailed stability analysis of the system, ascertaining that all four planets likely have masses between 0.19 and 0.84 M⁠, and are likely tidally locked, whereas a 4:3 mean-motion resonance chain for the inner three planets cannot be ruled out. Using atmospheric evolution models, we show that the prospect of extant primary atmospheres is highly unlikely on any of the planets. Barnard’s Star’s abnormally high Mg/Si ratio and low Th/Mg ratio imply planetary mantles which (a) are rich in (Mg,Fe)O ferropericlase; (b) have less than half the water capacity as Earth; (c) generate about half of the radiogenic heating as Earth; and (d) are cool and unlikely to have outgassed secondary atmospheres. Our analysis of this system presents an accessible set of first steps for the study of other nearby exoplanetary systems, as well as sub-Earth planets which will be increasingly discovered over the coming years.

Citation: Byrne, X., Guimond, C.M., Bonsor, A., et al. The Barnard’s Star planetary system: stability, composition, and evolution of four sub-Earth exoplanet. Monthly Notices of the Royal Astronomical Society, Volume 550, Issue 2 (2026).

DOI: https://doi.org/10.1093/mnras/stag1207

Study-related stories:

University of Cambridge – “Astronomers Find Nearby Planets To Be Small, Strange, and Utterly Uninhabitable”

Sci.News – “Barnard’s Star Planetary System May Be Filled with Water-Poor Rocky Worlds”

Daily Galaxy – “Scientists Studied a Nearby Star and Found Four Planets That Look Nothing Like Earth”

Video: The Risk of Self-Replicating Space Probes

Posted on by onespaceman2000
Credit: Pixabay

Earlier this month Cool Worlds Labs posted a video titled “Why Technological Civilizations Might Be Insanely Rare” that discusses the idea of self-replicating space probes.

The video starts with the assumption that self-replicating space probes, which have been discussed over the past 50 years, are something we should be able to achieve in the next few decades. That sounds like great news for space exploration. But there is a problem.

With each advance you often find a flaw, and in this case the flaw is that space probes will inevitably mutate into something destructive that slowly destroys exoplanets, then our own galaxy, and quite possibly other galaxies. So Professor David Kipping basically posits that such a probe can never be sent out because it is sure to eventually destroy the universe. This is quite a claim as we follow him through his calculations.

So the next question is why we are even here on Earth today since plenty of time has passed for the probe from another distant civilization to destroy us. The very fact that we are still here seems to indicate that no other civilization has ever sent out a self-replicating probe. And what does that mean? Could it mean there are no other civilizations? Or maybe no civilization survived to the point of sending such probes.

It is quite a mind twister worthy of your time. At the end of it, the overall question will change from “Why are we alone?” to “Why are we even here?” Or maybe, “How much longer will we be here?”

Don’t expect to get much sleep after watching this video.

Space Stories: A New Player in the Race for Mars, Swarming Exoplanet Seekers, and a Over-sized Pink Exoplanet

Posted on by onespaceman2000
Image (Credit): Martian dunes at Endurance Crater as viewed by NASA’s Mars Exploration Rover Opportunity. (NASA/JPL/Cornell)

Here are some recent space-related stories.

—Techcrunch: “NASA Picks Eric Schmidt’s Rocket Company for Mars Mission, Setting Up a Race with SpaceX“

Relativity Space — a rocket maker acquired by former Google executive chair Eric Schmidt last year after stumbling on the path to orbit — might just beat SpaceX to Mars. On Tuesday, NASA said it hired the company to build a spacecraft to house a suite of scientific instruments, launch it into space, and fly it to Mars. The structure of the contract is akin to the deals that NASA made with SpaceX to fly cargo to the International Space Station, or Firefly Aerospace to put a lander on the moon. The government agency handles the science, while the private company provides low-cost infrastructure.

—Universe Today: “Astronomers Want to Build a Swarm of Telescopes to Find LIFE“

Current plans for flagship telescopes in the 2040s are focused on answering a simple question – are we alone? Our best telescopes to date, such as the James Webb Space Telescope (JWST) have only given us tantalizing glimpses into the atmospheres or other worlds, but not enough to truly determine whether or not life as we know it exists there. Astronomers have been waiting for technology to catch up to their dreams of what is possible in terms of new types of telescopes, and recently the W.M. Keck Institute for Space Studies released a report detailing the Large Interferometer For Exoplanets (LIFE) mission, which they hope will help provide a definitive answer to that simple question.

—BBC Sky at Night: “The Pink Planet is So Weird, Astronomers Struggle to Define It. And They’ve Just Found It’s Covered in Salty Clouds“

There’s a pink planet, just a stone’s throw from Earth, that astronomers have been trying to decipher for over a decade. Known as the Pink Planet or, officially, GJ504b, this strange world orbits a Sun-like star 57 lightyears from Earth. Astronomers aren’t even sure if it’s a planet at all. About 25 times the mass of Jupiter, it’s so massive it’s on the boundary between giant planets and brown dwarfs (a type of failed star). But observations with the James Webb Space Telescope have revealed direct evidence for something rather strange at the Pink Planet: salty clouds.

Note: Here is the podcast version of this post.

The Nancy Grace Roman Space Telescope Is Taking Names

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Image (Credit): Artist’s rending of the Nancy Grace Roman Space Telescope. (NASA)

If you want to be part of a NASA mission, you have until July 12th to get your name to NASA so it can be added to the Nancy Grace Roman Space Telescope.

All of the submitted names will be uploaded to an secure digital card that will be attached to the space telescope. These names (and maybe yours) will then be stationed about one million miles away from Earth. As of this moment, NASA already has 145,949 names.

It is not the same as having an exoplanet named after you, but your name will be attached to the observatory that will be finding and analyzing exoplanets and more.

The current schedule calls for the Nancy Grace Roman Space Telescope to be launched on August 30th.

Go to this link to provide your name and learn more about the space telescope’s upcoming mission.

Space Stories: A Massachusetts Meteor, The Red Dwarf Diet, and an Extra Ice Giant in Our Solar System

Posted on by onespaceman2000
Image (Credit): A exploding meteor off the coast of Massachusetts as captured by the National Oceanic and Atmospheric Administration’s Geostationary Lightning Mapper on May 30, 2026. (National Oceanic and Atmospheric Administration)

Here are some recent space-related stories.

—WCVB5 News: “Meteor That Rattled Massachusetts Was Bigger Than First Thought, NASA Says“

A meteor that created a sonic boom heard by thousands in Massachusetts and parts of the Northeast Saturday afternoon was larger than previously believed, NASA said Monday. Scientists now say the meteor was 5 feet in diameter, up from the initial thought of 3 feet, NASA said. “The meteor was about 5 feet (1.6 meters) in diameter with a mass of 5.6 metric tons and entered Earth’s atmosphere at roughly 42,000 mph,” NASA said Monday. Scientists believe it traveled through the atmosphere from northwest to southeast for 26 miles before breaking up at an altitude of 31 miles and producing a meteorite fall into Cape Cod Bay.

—Royal Astronomical Society: “Red Dwarf Stars Detected ‘Eating’ Earth-like Planets“

Astronomers have found some of the strongest evidence yet that stars can swallow their own planets. A new study, published in Monthly Notices of the Astronomical Society, supports the long-held belief that young stars are capable of ‘eating’ nearby worlds as planetary systems form. Researchers from Keele University and the University of Exeter studied thousands of stars and found evidence that six different red dwarfs – the smallest, coolest, and most common type of star in the universe – had engulfed Earth-like rocky planets.

—Phys.org: “One of Our Planets May Be Missing, And it Could Explain Why the Solar System Looks the Way it Does“

Our solar system has two ice giants, Uranus and Neptune, but there may have been a third. According to a new study published in the journal Icarus, this extra world might have triggered a violent planetary shuffling billions of years ago that could have disrupted some of Jupiter’s and Uranus’s moons and possibly led to the formation of others.

Note: Here is the podcast version of this post.