astronomy

HD 130948

HD 130948 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 130948 rather than just read about it. In short: HD 130948 or HP Boötis is a variable star with 2 brown dwarfs in the constellation Boötes. With an apparent magnitude of 6.0, it is faintly visible to the naked eye under very good observing conditions.

Key takeaways

HD 130948 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 130948 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HD 130948 from memory before moving on to harder problems.

Reference excerpt

HD 130948 or HP Boötis is a variable star with 2 brown dwarfs in the constellation Boötes. With an apparent magnitude of 6.0, it is faintly visible to the naked eye under very good observing conditions. It has a stellar classification of G1V, which means it is a main sequence star with a mass and surface temperature that are similar to the Sun. The estimated age of HD 130948 is similar to the Sun at 4.7 billion years (Gyr) old, but it has a lower proportion of elements (63%) other than hydrogen or helium. However, a separate study in 2009 gave a much younger age of 0.5±0.3 Gyr and a higher metallicity that is very similar to the Sun. The younger age was favored in a 2019 study, based on coevality with the brown dwarf companions. Evolutionary models suggest that it is just reaching the end of its main sequence life. Eric J. Gaidos et al. observed the star in 1998 and 1999, and discovered that it is a variable star. It was given its variable star designation, HP Boötis, in 2006. In 2002, a pair of co-orbiting brown dwarfs were discovered in orbit around this star, named HD 130948 B and HD 130948 C. They were found using an adaptive optics instrument on the Gemini North 8m telescope in Hawaii. The brown dwarfs are similar to each other, with masses of 59.8±0.6 MJ and 56.3±0.5 MJ, radii of 1.00±0.01 RJ and 0.98±0.03 RJ, and temperatures of 1,950±30 K and 1,870±30 K for HD 130948 B and HD 130948 C, respectively. They orbit around each other with a period of 3,656 ± 4 days (10.010 ± 0.011 years), and the orbit around the primary star is poorly constrained due to insufficient orbital coverage, with an period in the order of centuries to dozens of thousand of years. The space velocity components of this star through the Milky Way galaxy are (U, V, W) = (−14.0, 14.7, −0.1).

Notes

References

Illustrations

Worked examples

Example 1 — a first encounter with HD 130948

Start with the simplest possible case. Write down what HD 130948 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 130948 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 130948 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 130948

In research: HD 130948 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 130948 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 130948 is common in secondary-school and first-year university syllabi. It links to neighbouring topics BY Draconis variables, Boötes, Bright Star Catalogue objects, so understanding it makes those chapters shorter.
In everyday life: Look for HD 130948 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 130948 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HD 130948 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 130948 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HD 130948 in simple terms?

Why does HD 130948 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 130948?

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 130948.