The Astonishing Tale of a Disintegrating Planet with a Comet-Like Tail

Imagine a planet so near its star that it’s breaking apart. Actually, this is BD+05 4868 Ab, a small rocky planet 140 light-years away. Being so close to its star makes it extremely hot. In fact, the heat melts its surface into liquid rock, or magma. Also, each time it orbits, it loses as much material as Mount Everest’s mass. Therefore, this creates a stunning comet-like tail that stretches 9 million kilometers. Thus, this disintegrating planet comet tail amazes astronomers and sparks a big question: why is BD+05 4868 Ab such a special find?

The Discovery of BD+05 4868 Ab

How NASA’s TESS Found the Breaking Planet

NASA’s Transiting Exoplanet Survey Satellite (TESS) helped find BD+05 4868 Ab. Basically, TESS looks for changes in a star’s brightness. These changes, called transits, happen when a planet moves in front of its star. In fact, it’s like a small shadow crossing the star.

For this planet, TESS noticed something strange. Particularly, the star’s light dimmed in an unusual way. The dimming was deeper and lasted longer than normal. Indeed, this showed a disintegrating planet losing pieces into space. Moreover, TESS data revealed the planet’s dramatic state and its comet-like tail of debris.

How MIT Astronomers Helped Confirm the Planet

MIT astronomers studied the TESS data to confirm the planet. Specifically, they looked at the strange transit signals and compared them to known ones. During this, they observed that the planet was very close to its star. Certainly, this explained the extreme heat and the planet’s disintegrating surface.

The team also figured out the planet’s orbit. Moreover, they found it takes only 30.5 hours to go around its star. This fast orbit makes the planet even more unique. The MIT team’s research shows how teamwork helps space discoveries.

Strange Transit Signals and What They Mean

The transit signals from BD+05 4868 Ab were unusual for these reasons:

• The transit depths ranged from 0.8% to 2.0%. This showed the planet was losing material.
• The signals were uneven. The start of the transit was short. The end of the transit lasted much longer.

These patterns showed a disintegrating planet comet tail. The debris tail made the light dim unevenly. This discovery proved how transit signals show a planet’s condition. It also showed the power of tools like TESS.

The Unique Characteristics of BD+05 4868 Ab

Very Close to Its Star

BD+05 4868 Ab is extremely close to its star. It is 20 times closer than Mercury is to the Sun. This makes the planet very hot and under strong gravity. The planet is tidally locked, so one side always faces the star. The other side stays in darkness.

One side of BD+05 4868 Ab always faces its star. This side gets very hot, causing the surface to melt. The heat turns the rock into gas, forming a thin atmosphere. Weak gravity and solar wind blow this material away. This shows how close the planet is to its star.

The planet’s orbit is very short, just 30.5 hours. This makes it one of the fastest-orbiting planets ever found.

A Molten Surface and Extreme Heat

The surface of BD+05 4868 Ab is melted rock. The heat from its star turns the surface into magma. Temperatures reach 1,600°C (3,000°F), which is extremely hot. In fact, the molten rock boils and escapes into space.

The heat creates a thin layer of vaporized rock around the planet. But this layer doesn’t last long. Additionally, the planet’s weak gravity and solar wind strip it away quickly.

How the Comet-Like Tail Forms

The comet-like tail is the planet’s most amazing feature. The planet loses material as it orbits its star. Then, the molten rock turns into gas and dust, forming a trail. This is like a comet’s tail, but with rocky material instead of ice.

• BD+05 4868 Ab orbits its star every 30.5 hours. This causes extreme heat that melts the surface.
• The heat makes the planet lose mass, creating a comet-like tail.
• The tail is made of rocky dust, not ice like a comet’s tail.

This tail shows the planet is breaking apart over time.

Losing Material Quickly

BD+05 4868 Ab loses material very fast. Every 30.5 hours, it sheds as much mass as Mount Everest. Its weak gravity and small size make this happen faster. The heat and solar wind speed up the process.

• The planet loses as much mass as Mount Everest every 30.5 hours.
• Weak gravity and small size make the disintegration faster.
• The dust tail, 9 million kilometers long, shows how extreme this loss is.

This rapid loss means the planet might not last long. Scientists think it could fully break apart in 1 to 2 million years.

A Huge 9-Million-Kilometer Tail

The disintegrating planet comet tail is enormous. It is 9 million kilometers long, over 20 times the Earth-Moon distance. The tail wraps around half of the planet’s orbit, making it stunning to see.

TESS helped scientists study this tail. It found uneven transit signals, showing a dust tail. Larger dust particles are at the front, and smaller ones are at the back. Therefore, this proves the tail is made of rocky debris.

The tail is made of mineral dust from the planet’s surface. This makes BD+05 4868 Ab a rare example of a disintegrating planet.

The Rarity of Disintegrating Planets

How Often Do Planets Break Apart in Space?

Planets breaking apart are very uncommon. Scientists think only 2% of planets might show signs of breaking apart through transit signals. Among millions of white dwarfs (WDs) in the galaxy, only a few have such planets. Experts believe up to 1,000 systems with breaking planets could exist. But finding them is hard because they are rare and don’t last long.

Feature	Estimate
Chance of transit signals	About 2%
Number of WDs in galaxy	1 million
Likely occurrence rate	10%
Possible systems found	Up to 1,000

Comparing BD+05 4868 Ab to Other Breaking Planets

Out of nearly 6,000 known exoplanets, only a few are breaking apart. Before BD+05 4868 Ab, scientists had found just three such planets. One example is K2-22b, which has a changing dust tail. The Kepler mission also found planets losing material due to heat. These discoveries show how rare breaking planets are.

• Only a few breaking planets exist among 6,000 exoplanets.
• K2-22b is one of four known breaking planets.
• Dust tails show planets losing material from extreme heat.

Why BD+05 4868 Ab Is Special

BD+05 4868 Ab is different from other breaking planets. It loses material very quickly and has a huge dust tail. Every 30.5 hours, it sheds as much mass as Mount Everest. Its tail, 9 million kilometers long, is the biggest ever seen. These features make it the most dramatic example of a breaking planet.

How the Host Star Causes the Planet to Break Apart

The star BD+05 4868 Ab orbits plays a big role in its disintegration. Basically, the planet circles a K-dwarf star with a brightness of V = 10.16. The star’s heat and radiation melt the planet’s surface. The star is older than the Sun, which affects how fast the planet loses material. These conditions make the planet break apart.

Feature	Details
Star Brightness	Brightness of V = 10.16 makes the planet’s features easier to see.
Star Type	The star is a K-dwarf, creating a hot environment for the planet.
Star Age	The star is older than the Sun, speeding up the planet’s disintegration.
Material Loss Rate	The planet loses material at 10 Earth masses per billion years.
Dust Tail Features	The dust tail shows active breaking processes on the planet.

Implications for Planetary Science

Learning About How Rocky Planets Change Over Time

BD+05 4868 Ab gives scientists a rare chance to study rocky planets in harsh conditions. Its breaking apart shows what happens to planets near intense heat and radiation. Being so close to a star changes the planet’s surface and atmosphere. The melted surface and fast material loss show how rocky planets can change.

This discovery also helps scientists learn how long planets last. Following this, experts think BD+05 4868 Ab will completely break apart in 1 to 2 million years. Thus, watching this process shows what happens to planets at the end of their life.

What the Comet-Like Tail Tells Us About the Planet’s Makeup

The disintegrating planet comet tail is not just amazing to look at. It also gives clues about what the planet is made of. Also, the dust and gas in the tail come from the planet’s surface. By studying this, scientists can figure out the planet’s materials.

The James Webb Space Telescope (JWST) will study the tail’s light to find out what minerals are in the comet-like tail of BD+05 4868 Ab.

This research will help scientists understand different rocky planets. It might even show if the planet has minerals like those on Earth.

How the James Webb Space Telescope Will Help Future Studies

The James Webb Space Telescope (JWST) will be very important for studying breaking planets. In fact, its tools can study the dust and gas escaping from BD+05 4868 Ab in great detail.

JWST uses special methods to study a planet’s atmosphere. It looks at how a star’s light changes when a planet passes in front of it. This shows how the light interacts with the planet’s atmosphere. Additionally, scientists can find out what molecules are there and learn about the planet’s chemistry. Indeed, this is key for understanding planets like BD+05 4868 Ab.

How This Discovery Helps Us Learn About Other Planets

Finding a breaking planet like BD+05 4868 Ab shows how new tools are changing space science. NASA’s TESS found strange signals that led to this big discovery. Actually, these signals showed the planet’s fast material loss and its huge dust tail.

• TESS watches for dips in starlight to find planets.
• JWST will study the dust tail to learn about rocky planets.
• These tools help scientists understand how planets form and change.

This discovery shows why using many tools together is important. It also proves that studying extreme planets teaches us more about the universe.

BD+05 4868 Ab is a rare disintegrating planet with a 9-million-kilometer comet-like tail. Additionally, its unique features and fast material loss make it special. Powerful tools like JWST and TESS will:

• Examine what rocky planets are made of.
• Find more planets breaking apart.
• Study how stars affect nearby planets.

These tools will lead to amazing discoveries soon.

References

Astronomers discover a planet that’s rapidly disintegrating, producing a comet-like tail. (2025, April 22). MIT News | Massachusetts Institute of Technology. https://news.mit.edu/2025/astronomers-discover-planet-thats-rapidly-disintegrating-producing-comet-tail-0422

NASA. (2025, March 28). BD+05 4868 A b – NASA Ciencia. NASA Science. https://ciencia.nasa.gov/exoplanet-catalog/bd05-4868-a-b/

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