astronomy

HD 142415

HD 142415 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 142415 rather than just read about it. In short: HD 142415 is a single star in the southern constellation of Norma, positioned next to the southern constellation border with Triangulum Australe and less than a degree to the west of NGC 6025. With an apparent visual magnitude of 7.33, it is too faint to be visible to the naked eye.

Key takeaways

HD 142415 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 142415 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HD 142415 from memory before moving on to harder problems.

Reference excerpt

HD 142415 is a single star in the southern constellation of Norma, positioned next to the southern constellation border with Triangulum Australe and less than a degree to the west of NGC 6025. With an apparent visual magnitude of 7.33, it is too faint to be visible to the naked eye. The distance to this star is 116 light years from the Sun based on parallax, but it is drifting closer with a radial velocity of −12 km/s. It is a candidate member of the NGC 1901 open cluster of stars. This is an ordinary G-type main-sequence star with a stellar classification of G1V. It has been identified as a solar twin by Datson et al. (2012), which means its physical properties are very similar to the Sun. It has 10% more mass than the Sun but only a 3% larger radius. The star is estimated to be 1.6 billion years old and is spinning with a projected rotational velocity of 4.2 km/s. It is radiating 1.16 times the luminosity of the Sun from its photosphere at an effective temperature of 5,869 K. The star is currently known to have one planet, designated HD 142415 b. This was detected via the radial velocity method and announced in 2004. The orbital period is just over a year, which made a determination of the orbital eccentricity more difficult due to undersampling over part of the orbit, in combination with jitter. The authors chose to pin the eccentricity value to 0.5, although solutions in the range 0.2–0.8 would be equally plausible.

See also HD 141937 HD 142022 List of extrasolar planets

References

Worked examples

Example 1 — a first encounter with HD 142415

Start with the simplest possible case. Write down what HD 142415 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 142415 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 142415 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 142415

In research: HD 142415 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 142415 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 142415 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Durchmusterung objects, G-type main-sequence stars, Henry Draper Catalogue objects, so understanding it makes those chapters shorter.
In everyday life: Look for HD 142415 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 142415 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HD 142415 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 142415 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HD 142415 in simple terms?

Why does HD 142415 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 142415?

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 142415.