astronomy

GJ 4256 b

GJ 4256 b is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand GJ 4256 b rather than just read about it. In short: GJ 4256 b (also known as TOI-6255 b) is an Earth-size terrestrial exoplanet located around 66.21 light years (20.3 parsecs) from Earth orbiting the red dwarf star GJ 4256. The planet has a mass of 1.44 ±0.14 Earths and a radius of 1.079 ±0.065 Earths. lt orbits extremely close to its parent star at a distance of 0.0054 AU.

Key takeaways

GJ 4256 b belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect GJ 4256 b to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of GJ 4256 b from memory before moving on to harder problems.

Reference excerpt

GJ 4256 b (also known as TOI-6255 b) is an Earth-size terrestrial exoplanet located around 66.21 light years (20.3 parsecs) from Earth orbiting the red dwarf star GJ 4256. The planet has a mass of 1.44 ±0.14 Earths and a radius of 1.079 ±0.065 Earths. lt orbits extremely close to its parent star at a distance of 0.0054 AU. This makes GJ 4256 classed as an ultra-short period (USP) planet with an orbital period of just 0.23 days. The close distance of this planet places significant tidal deformation on the planet. This makes GJ 4256 b appear similar in shape to an egg and making it one of the most tidally distorted terrestrial planets discovered so far. It also means that GJ 4256 b also has a magma ocean making it a lava planet with a temperature of 1300 Kelvin. The planet may be a favorable target for the study of magnetic interactions between the star and its planets which may cause interior melting and quicken orbital decay. GJ 4256 is a top target for phase-curve observations by the James Webb Space Telescope (JWST).

Discovery GJ 4256 b was discovered in 2024 using the transit method. The star was observed in September of 2019 and 2022 using the Transiting Exoplanet Survey Satellite (TESS). It was also observed with the CARMENES instrument at the Calar Alto Observatory. If GJ 4156 had a companion star, that star could have produced false-positive transit signals. To remove the possibility of false-positives, the star was observed to look for any companion stars with Palomar/PHARO. There were no companion stars found. After the detection of GJ 4256 b, there was a search for additional planets in the systems. A transit signal was uncovered designated TOI-6255.02. If it were a planet, it would have an orbit of 14.48 days. This signal was also reported on the ExoFOP website by a citizen scientist named Alton Spencer. However due to a lack of additional prominent signals and a substantial flux occurring in a nearby background star, the TOI-6255.02 signal was likely a false-positive.

Physical characteristics The first is a two-layer interior model with an iron core that is surrounded by a silicate mantle. This would make the iron core mass fraction (CMF) be 0.45 ±0.32. The second is the SUPEREARTH model which is able to distinguish between the true iron mass fraction (Fe-CMF of 0.38 ± 0.15) which may be due to the silicate mantle containing iron while the iron core containing other elements. Results show that the simpler two-layered model seems to be more accurate. The planet magnetically interacts with its star that is analogous to the interaction between Jupiter and one of its moons Io.

Tidal deformation The planet orbits so close to the host star that it has nearly passed the roche limit. The expected tidal forces caused by the star would likely have deformed the planet pulling it into an triaxial ellipsoid (egg-like shape) with its long axis that is ~10% longer than the short axis. It is possible that the tidal distortion may be significantly greater than what Love theory predicts with the long axis being 15% longer than the short axis. It experiences tidal orbital decay and it is predicted that in around 400 million years, the planet will have passed the roche limit of parent star and be ripped apart and engulfed by the star. GJ 4256 is likely not in the process of disintegrating (see: catastrophically evaporating planets). Examples of disintegrating planets, all of which have orbital periods that are greater than GJ 4256, include KOI-2700 b, KIC 12557548 b, K2-22b and BD+05 4868Ab. Evidence for disintegration would be asymmetries in the transit data and debris material up to a kilometer in size would be detectable. However no evidence for disintegration has been observed.

References

Illustrations

Worked examples

Example 1 — a first encounter with GJ 4256 b

Start with the simplest possible case. Write down what GJ 4256 b claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to GJ 4256 b before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about GJ 4256 b ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of GJ 4256 b

In research: GJ 4256 b appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses GJ 4256 b in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: GJ 4256 b is common in secondary-school and first-year university syllabi. It links to neighbouring topics Exoplanets discovered in 2024, Transiting exoplanets, so understanding it makes those chapters shorter.
In everyday life: Look for GJ 4256 b outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study GJ 4256 b in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what GJ 4256 b means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain GJ 4256 b out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is GJ 4256 b in simple terms?

Why does GJ 4256 b matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study GJ 4256 b?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on GJ 4256 b.