astronomy

HD 148427

HD 148427 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 HD 148427 rather than just read about it. In short: HD 148427, formally named Timir, is a 7th-magnitude star approximately 230 light-years away in the constellation Ophiuchus. It has a spectral type of K0III/IV, indicating a K-type star that is close to becoming a red giant.

Key takeaways

HD 148427 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect HD 148427 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HD 148427 from memory before moving on to harder problems.

Reference excerpt

HD 148427, formally named Timir, is a 7th-magnitude star approximately 230 light-years away in the constellation Ophiuchus. It has a spectral type of K0III/IV, indicating a K-type star that is close to becoming a red giant. While some sources describe it as a subgiant, stellar evolution models suggest it is already on the red giant branch. Its mass is 45% greater than the Sun, and it is three times the size and six times more luminous, although its age is 2.5 billion years, younger than the Sun.

Companion In August 2009, it was found to have a companion in orbit (HD 148427 b or Tondra) with a minimum mass of 0.96 MJ, suggesting it is a gas giant planet, and an orbital period of 331.5 days. An astrometric study in 2020 suggested that this object has a nearly face-on orbit, with a true mass between 27 and 345 MJ. This would make it either a brown dwarf or a low-mass red dwarf star, rather than a planet. However, a 2026 study instead found an edge-on orbit, indicating a planetary mass. While this study's measurements are uncertain, they suggest the companion is likely substellar.

Naming HD 148427 and HD 148427 b were chosen as part of the 2019 NameExoWorlds campaign organised by the International Astronomical Union, which assigned each country a star and planet to be named. HD 148427 was assigned to Bangladesh. The winning name for the star was Timir meaning darkness in the Bengali language, alluding to the star being far away in the darkness of space. The winning name for the companion was Tondra meaning nap in the Bengali language, alluding to the symbolic notion that the object was asleep until discovered.

Worked examples

Example 1 — a first encounter with HD 148427

Start with the simplest possible case. Write down what HD 148427 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 HD 148427 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 HD 148427 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 HD 148427

In research: HD 148427 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 HD 148427 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: HD 148427 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Durchmusterung objects, Henry Draper Catalogue objects, Hipparcos objects, so understanding it makes those chapters shorter.
In everyday life: Look for HD 148427 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 HD 148427 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HD 148427 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 HD 148427 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HD 148427 in simple terms?

Why does HD 148427 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 HD 148427?

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 HD 148427.