astronomy

GJ 1289 b

GJ 1289 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 1289 b rather than just read about it. In short: GJ 1289 b is a sub-Neptune exoplanet orbiting the red dwarf star GJ 1289, located approximately 8.86 parsecs (≈29 light-years) from the Sun. It was discovered using radial-velocity measurements with the near-infrared spectropolarimeter SPIRou at the Canada–France–Hawaii Telescope over multiple years, revealing a minimum mass of 6.27 ± 1.25 Earth masses and a nearly circular orbit with a period of 111.74 days.

Key takeaways

GJ 1289 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 1289 b to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of GJ 1289 b from memory before moving on to harder problems.

Reference excerpt

GJ 1289 b is a sub-Neptune exoplanet orbiting the red dwarf star GJ 1289, located approximately 8.86 parsecs (≈29 light-years) from the Sun. It was discovered using radial-velocity measurements with the near-infrared spectropolarimeter SPIRou at the Canada–France–Hawaii Telescope over multiple years, revealing a minimum mass of 6.27 ± 1.25 Earth masses and a nearly circular orbit with a period of 111.74 days. The host star, an M4.5V fully convective red dwarf with a mass of 0.21 solar masses, exhibits a strong large-scale dipolar magnetic field of 200–240 G and a rotation period of ~73.7 days, which is distinct from the planet's orbital period. The planet's orbital distance places it beyond the conventional habitable zone of its cool, low-luminosity host, though it may still have a temperate atmosphere, making it a target for further study. Its discovery is notable for demonstrating the detection of planets around fully convective M dwarfs, whose magnetic activity differs significantly from that of partly convective stars, and for showing that low-amplitude radial-velocity signals can be reliably extracted even in the presence of strong stellar magnetic fields.

References

Worked examples

Example 1 — a first encounter with GJ 1289 b

Start with the simplest possible case. Write down what GJ 1289 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 1289 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 1289 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 1289 b

In research: GJ 1289 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 1289 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 1289 b is common in secondary-school and first-year university syllabi. It links to neighbouring topics Exoplanet stubs, Exoplanets discovered in 2024, so understanding it makes those chapters shorter.
In everyday life: Look for GJ 1289 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 1289 b in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what GJ 1289 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 1289 b out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is GJ 1289 b in simple terms?

Why does GJ 1289 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 1289 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 1289 b.