astronomy

GJ 3470

GJ 3470 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 3470 rather than just read about it. In short: GJ 3470, proper name Kaewkosin, is a red dwarf star located in the constellation of Cancer, 96 light-years (29 parsecs) away from Earth. With a faint apparent magnitude of 12.3, it is not visible to the naked eye.

Key takeaways

GJ 3470 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 3470 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of GJ 3470 from memory before moving on to harder problems.

Reference excerpt

GJ 3470, proper name Kaewkosin, is a red dwarf star located in the constellation of Cancer, 96 light-years (29 parsecs) away from Earth. With a faint apparent magnitude of 12.3, it is not visible to the naked eye. It hosts one known exoplanet, GJ 3470 b.

Nomenclature The designation GJ 3470 comes from the Gliese Catalogue of Nearby Stars. This star was first included in the Third Catalogue of Nearby Stars, published in 1991 by Gliese and Jahreiß, hence the GJ prefix usually used for this star. In August 2022, GJ 3470 and its planet were included among 20 planetary systems to be named by the third NameExoWorlds project. The approved names, proposed by a team from Thailand, were announced in June 2023. GJ 3470 is named Kaewkosin and its planet is named Phailinsiam, after names of precious stones in the Thai language.

Properties The star has a mass of 0.539 solar masses, a radius of 0.547 solar radii, and a temperature of about 3,652 K (3,379 °C; 6,114 °F). It is about 0.3-3 billion years old, with a metallicity of 0.2 Fe/H and a rotation period of 21.54 days. The star exhibits strong stellar activity, with three ultraviolet flares detected by 2021.

Planetary system At least one exoplanet has been discovered orbiting GJ 3470 at a distance of 0.035 astronomical units. The exoplanet, which is called GJ 3470 b, is a hot Neptune with an orbital period of 3.3 days. It was discovered in 2012 using radial velocity observations from HARPS, and transit observations from TRAPPIST. The planet's atmosphere has been studied in detail, finding it to be composed mainly of hydrogen and helium, with Rayleigh scattering having been observed. GJ 3470 b is losing mass to its star at a rate of about 1010 g/s.

Claims of additional planets In July 2020, a group of amateur astronomers reported a new exoplanet candidate in an arXiv preprint, which they hypothesized to be the size of Saturn and inside the system's habitable zone, along with twelve tentative transits from not yet characterized exoplanets in the same star system. If confirmed, GJ 3470 c would become the second exoplanet discovered by amateur astronomers, after KPS-1b, an exoplanet discovered by Ural State Technical University using amateur data. The new GJ 3470 candidate was discovered with amateur data and through a project led by amateur astronomers. The study in question has not been published in any scientific journal, nor has it been peer reviewed. Similarly, on 21 April 2023, the same group of amateur astronomers reported two new exoplanet candidates co-orbiting, in a horseshoe exchange orbit, close to the star. If confirmed, this would be the first ever discovery of co-orbiting exoplanets. However, again, the study in question is only in preprint form on arXiv, and it has not been peer reviewed and published in a respected scientific journal. As reported in a follow-up arXiv paper also by amateur astronomers, data from TESS rules out the existence of all three of these claimed planets. Thus, the "transits" observed by the amateur group were likely caused by visual artifacts. Radial velocity data can also rule out planets of the expected mass at the claimed periods, suggesting that if the claimed planets did exist, they would have very low densities. Unrelated to the previous amateur claims, the results of a search for trojan companions of 95 transiting exoplanets by the TROY project were published in Astronomy & Astrophysics in 2024. One strong candidate was identified by this project - a possible 2.6±0.7 M🜨 trojan of GJ 3470 b orbiting at its L5 Lagrange point, based on radial velocity data. However, no transits of this candidate were detected, indicating that if it transits its radius cannot be larger than that of Earth.

Worked examples

Example 1 — a first encounter with GJ 3470

Start with the simplest possible case. Write down what GJ 3470 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 3470 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 3470 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 3470

In research: GJ 3470 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 3470 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 3470 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cancer (constellation), Flare stars, Gliese and GJ objects, so understanding it makes those chapters shorter.
In everyday life: Look for GJ 3470 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 3470 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what GJ 3470 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 3470 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is GJ 3470 in simple terms?

Why does GJ 3470 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 3470?

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 3470.