The Times Australia
The Times World News

.

A quarter of Sun-like stars eat their own planets, according to new research

  • Written by Lorenzo Spina, Postdoctoral Research Fellow, Italian National Institute for Astrophysics, and formerly Research Fellow, Monash University

How rare is our Solar System? In the 30 years or so since planets were first discovered orbiting stars other than our Sun, we have found that planetary systems are common in the Galaxy. However, many of them are quite different from the Solar System we know.

The planets in our Solar System revolve around the Sun in stable and almost circular paths, which suggests the orbits have not changed much since the planets first formed. But many planetary systems orbiting around other stars have suffered from a very chaotic past.

The relatively calm history of our Solar System has favoured the flourishing of life here on Earth. In the search for alien worlds that may contain life, we can narrow down the targets if we have a way to identify systems that have had similarly peaceful pasts.

Our international team of astronomers has tackled this issue in research published in Nature Astronomy[1]. We found that between 20% and 35% of Sun-like stars eat their own planets, with the most likely figure being 27%.

This suggests at least a quarter of planetary systems orbiting stars similar to the Sun have had a very chaotic and dynamic past.

Chaotic histories and binary stars

Astronomers have seen several exoplanetary systems in which large or medium-sized planets have moved around significantly. The gravity of these migrating planets may also have perturbed the paths of the other planets or even pushed them into unstable orbits.

In most of these very dynamic systems, it is also likely some of the planets have fallen into the host star. However, we didn’t know how common these chaotic systems are relative to quieter systems like ours, whose orderly architecture has favoured the flourishing of life on Earth.

A quarter of Sun-like stars eat their own planets, according to new research Binary stars form at the same time from a single cloud of gas, so they usually contain exactly the same mix of elements. ALMA (ESO/NAOJ/NRAO), Alves et al.[2]

Even with the most precise astronomical instruments available, it would be very hard to work this out by directly studying exoplanetary systems. Instead, we analysed the chemical composition of stars in binary systems.

Binary systems are made up of two stars in orbit around one another. The two stars generally formed at the same time from the same gas, so we expect they should contain the same mix of elements.

However, if a planet falls into one of the two stars, it is dissolved in the star’s outer layer. This can modify the chemical composition of the star, which means we see more of the elements that form rocky planets – such as iron – than we otherwise would.

Traces of rocky planets

We inspected the chemical makeup of 107 binary systems composed of Sun-like stars by analysing the spectrum of light they produce. From this, we established how many of stars contained more planetary material than their companion star.

We also found three things that add up to unambiguous evidence that the chemical differences observed among binary pairs were caused by eating planets.

First, we found that stars with a thinner outer layer have a higher probability of being richer in iron than their companion. This is consistent with planet-eating, as when planetary material is diluted in a thinner out layer it makes a bigger change to the layer’s chemical composition.

Second, stars richer in iron and other rocky-planet elements also contain more lithium than their companions. Lithium is quickly destroyed in stars, while it is conserved in planets. So an anomalously high level of lithium in a star must have arrived after the star formed, which fits with the idea that the lithium was carried by a planet until it was eaten by the star.

Third, the stars containing more iron than their companion also contain more than similar stars in the Galaxy. However, the same stars have standard abundances of carbon, which is a volatile element and for that reason is not carried by rocks. Therefore these stars have been chemically enriched by rocks, from planets or planetary material.

The hunt for Earth 2.0

These results represent a breakthrough for stellar astrophysics and exoplanet exploration. Not only have we found that eating planets can change the chemical composition of Sun-like stars, but also that a significant fraction of their planetary systems underwent a very dynamical past, unlike our solar system.

Finally, our study opens the possibility of using chemical analysis to identify stars that are more likely to host true analogues of our calm solar system.

There are millions of relatively nearby stars similar to the Sun. Without a method to identify the most promising targets, the search for Earth 2.0 will be like the search for the proverbial needle in a haystack.

Read more https://theconversation.com/a-quarter-of-sun-like-stars-eat-their-own-planets-according-to-new-research-166904

Times Magazine

Headless CMS in Digital Twins and 3D Product Experiences

Image by freepik As the metaverse becomes more advanced and accessible, it's clear that multiple sectors will use digital twins and 3D product experiences to visualize, connect, and streamline efforts better. A digital twin is a virtual replica of ...

The Decline of Hyper-Casual: How Mid-Core Mobile Games Took Over in 2025

In recent years, the mobile gaming landscape has undergone a significant transformation, with mid-core mobile games emerging as the dominant force in app stores by 2025. This shift is underpinned by changing user habits and evolving monetization tr...

Understanding ITIL 4 and PRINCE2 Project Management Synergy

Key Highlights ITIL 4 focuses on IT service management, emphasising continual improvement and value creation through modern digital transformation approaches. PRINCE2 project management supports systematic planning and execution of projects wit...

What AI Adoption Means for the Future of Workplace Risk Management

Image by freepik As industrial operations become more complex and fast-paced, the risks faced by workers and employers alike continue to grow. Traditional safety models—reliant on manual oversight, reactive investigations, and standardised checklist...

From Beach Bops to Alpine Anthems: Your Sonos Survival Guide for a Long Weekend Escape

Alright, fellow adventurers and relaxation enthusiasts! So, you've packed your bags, charged your devices, and mentally prepared for that glorious King's Birthday long weekend. But hold on, are you really ready? Because a true long weekend warrior kn...

Effective Commercial Pest Control Solutions for a Safer Workplace

Keeping a workplace clean, safe, and free from pests is essential for maintaining productivity, protecting employee health, and upholding a company's reputation. Pests pose health risks, can cause structural damage, and can lead to serious legal an...

The Times Features

Duke of Dural to Get Rooftop Bar as New Owners Invest in Venue Upgrade

The Duke of Dural, in Sydney’s north-west, is set for a major uplift under new ownership, following its acquisition by hospitality group Good Beer Company this week. Led by resp...

Prefab’s Second Life: Why Australia’s Backyard Boom Needs a Circular Makeover

The humble granny flat is being reimagined not just as a fix for housing shortages, but as a cornerstone of circular, factory-built architecture. But are our systems ready to s...

Melbourne’s Burglary Boom: Break-Ins Surge Nearly 25%

Victorian homeowners are being warned to act now, as rising break-ins and falling arrest rates paint a worrying picture for suburban safety. Melbourne residents are facing an ...

Exploring the Curriculum at a Modern Junior School in Melbourne

Key Highlights The curriculum at junior schools emphasises whole-person development, catering to children’s physical, emotional, and intellectual needs. It ensures early year...

Distressed by all the bad news? Here’s how to stay informed but still look after yourself

If you’re feeling like the news is particularly bad at the moment, you’re not alone. But many of us can’t look away – and don’t want to. Engaging with news can help us make ...

The Role of Your GP in Creating a Chronic Disease Management Plan That Works

Living with a long-term condition, whether that is diabetes, asthma, arthritis or heart disease, means making hundreds of small decisions every day. You plan your diet against m...