astronomy

LP 890-9

LP 890-9 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 LP 890-9 rather than just read about it. In short: LP 890-9, also known as SPECULOOS-2 or TOI-4306, is a red dwarf star located 105 light-years (32 pc) away from the Solar System in the constellation of Eridanus. The star has 12% the mass and 15% the radius of the Sun, and a temperature of 2,871 K (2,598 °C; 4,708 °F).

Key takeaways

LP 890-9 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect LP 890-9 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of LP 890-9 from memory before moving on to harder problems.

Reference excerpt

LP 890-9, also known as SPECULOOS-2 or TOI-4306, is a red dwarf star located 105 light-years (32 pc) away from the Solar System in the constellation of Eridanus. The star has 12% the mass and 15% the radius of the Sun, and a temperature of 2,871 K (2,598 °C; 4,708 °F). It is extremely faint and, with an apparent magnitude of 18, is the faintest star with exoplanets discovered by the Transiting Exoplanet Survey Satellite.

Planetary system In 2022, two exoplanets were discovered in orbit around this star. The first planet, LP 890-9 b, was initially identified using TESS. Further observations using SPECULOOS confirmed this planet and discovered a second planet, LP 890-9 c. Both planets are likely terrestrial planets, somewhat larger than Earth. The outer planet LP 890-9 c orbits within the habitable zone, and is a favorable target for atmospheric characterization using JWST. LP 890-9 c orbits near the inner edge of the conservative habitable zone, and models differ as to whether the planet is more likely to resemble Earth or Venus. Spectra from JWST should make it possible to distinguish between these two scenarios. The planet is tidally locked to its host, meaning it has no day-night cycle like Earth. While the planet's location in the habitable zone suggests a strong possibility of an Earth-like atmosphere and climate, the planet's large size may count against its habitability. In addition, the planet is close enough to its star that the powerful radiation may reduce its chances of habitability. Another challenge for the potential habitability of LP 890-9 c is the magma ocean that would have formed during its infancy, which may have lasted for up to 50 million years. This could have removed eight Earth oceans’ worth of water and left 2000 bars of oxygen in its atmosphere, although if its initial hydrogen envelope had 0.1 Earth masses, no water would have been lost. Furthermore, the circulation of the planets orbit would take about 7 billion years, producing hundreds of terawatts of tidal heating. The habitability of LP 890-9 c depends heavily on the initial volatile content and properties and the planet is unlikely to support life.

See also Proxima Centauri - Closest star to the Sun, a red dwarf that hosts terrestrial planets with one inside the habitable zone Teegarden's Star - A nearby red dwarf in the constellation of Aries with two known terrestrial planets in the habitable zone TRAPPIST-1 - An ultra-cool red dwarf in the constellation of Aquarius Wolf 359 - A planet-hosting nearby ultra-cool red dwarf in the Leo constellation

Notes

References

Worked examples

Example 1 — a first encounter with LP 890-9

Start with the simplest possible case. Write down what LP 890-9 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 LP 890-9 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 LP 890-9 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 LP 890-9

In research: LP 890-9 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 LP 890-9 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: LP 890-9 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Eridanus (constellation), M-type main-sequence stars, Planetary systems with two confirmed planets, so understanding it makes those chapters shorter.
In everyday life: Look for LP 890-9 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 LP 890-9 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what LP 890-9 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 LP 890-9 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is LP 890-9 in simple terms?

Why does LP 890-9 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 LP 890-9?

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 LP 890-9.