astronomy

Gliese 15 Ab

Gliese 15 Ab 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 Gliese 15 Ab rather than just read about it. In short: Gliese 15 Ab (GJ 15 Ab), also called Groombridge 34 Ab, rarely called GX Andromedae b, is an extrasolar planet approximately 11 light-years away in the constellation of Andromeda. It is found in the night sky orbiting the star Gliese 15 A, which is at right ascension 00h 18m 22.89s and declination +44° 01′ 22.6″.

Key takeaways

Gliese 15 Ab belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Gliese 15 Ab to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Gliese 15 Ab from memory before moving on to harder problems.

Reference excerpt

Gliese 15 Ab (GJ 15 Ab), also called Groombridge 34 Ab, rarely called GX Andromedae b, is an extrasolar planet approximately 11 light-years away in the constellation of Andromeda. It is found in the night sky orbiting the star Gliese 15 A, which is at right ascension 00h 18m 22.89s and declination +44° 01′ 22.6″.

Discovery It was discovered in August 2014, deduced from analysis of the radial velocities of the parent star by the Eta-Earth Survey using HIRES at Keck Observatory. It has around 5.35 ± 0.75 Earth masses, and is thought to be a Super-Earth with a diameter greater than that of the Earth. However, researchers using the CARMENES spectrograph failed to detect the planet in 2017. The detection of planet was recovered in 2018, with revised minimum mass of 3.03 M🜨.

Orbit Gliese 15 Ab has a close inner orbit around Gliese 15 A with a semi-major axis of only 0.0717 ± 0.0034 AU, making an orbital period that is just a little longer than 11.4 days, the orbit appears to be relatively circular, with an orbital eccentricity of about 0.12. It orbits too close to Gliese 15 A to be located in the habitable zone and is unlikely to harbour life.

Notes

References

External links Open Exoplanet Catalogue entry Archived 2019-04-16 at the Wayback Machine

Worked examples

Example 1 — a first encounter with Gliese 15 Ab

Start with the simplest possible case. Write down what Gliese 15 Ab 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 Gliese 15 Ab 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 Gliese 15 Ab 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 Gliese 15 Ab

In research: Gliese 15 Ab 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 Gliese 15 Ab 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: Gliese 15 Ab is common in secondary-school and first-year university syllabi. It links to neighbouring topics Andromeda (constellation), Exoplanets detected by radial velocity, Exoplanets discovered in 2014, so understanding it makes those chapters shorter.
In everyday life: Look for Gliese 15 Ab 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.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Gliese 15 Ab” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Gliese 15 Ab in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Gliese 15 Ab 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 Gliese 15 Ab out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Gliese 15 Ab in simple terms?

Why does Gliese 15 Ab 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 Gliese 15 Ab?

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 Gliese 15 Ab.