astronomy

HD 11964

HD 11964 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 11964 rather than just read about it. In short: HD 11964 is a binary star system located 110 light-years away from the Sun in the equatorial constellation of Cetus. It is visible in binoculars or a telescope but is too faint to be seen with the naked eye, having an apparent visual magnitude of 7.51.

Key takeaways

HD 11964 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 11964 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HD 11964 from memory before moving on to harder problems.

Reference excerpt

HD 11964 is a binary star system located 110 light-years away from the Sun in the equatorial constellation of Cetus. It is visible in binoculars or a telescope but is too faint to be seen with the naked eye, having an apparent visual magnitude of 7.51. The system is drifting closer to the Sun with a radial velocity of −9 km/s. Two extrasolar planets have been confirmed to orbit the primary.

Properties The primary, component A, is a G-type main-sequence star with a stellar classification of G9VCN+1. The suffix notation indicates an overabundance of the cyano radical in the spectrum. Houk and Swift (1999) found a class of G8IV, suggesting it is instead a more evolved subgiant star. It is around seven billion years old and is spinning slowly with a projected rotational velocity of 1.5 km/s. The star has 1.1 times the mass of the Sun and 2.2 times the Sun's radius. It is radiating 2.9 times the luminosity of the Sun from its photosphere at an effective temperature of 5,321 K. A wide binary companion star was discovered in 2000. This secondary, designated component B, has a visual magnitude of 11.11 and lies at an angular separation of 29.7″ along a position angle of 134°, as of 2015. It is a red dwarf with a class of M0V, and has just 0.6 times the Sun's radius. It is radiating 0.085 times the Sun's luminosity at an effective temperature of 4,033 K.

Planetary system In August 2005, two planets were discovered orbiting the star, the innermost like Neptune and another like Jupiter orbiting at 3.34 AU. However, the second planet (HD 11964 b) was not confirmed until May 2007. In September 2007, P.C. Gregory claimed that there was a third planet in the system on the basis of Bayesian analysis of the radial velocity data. The planet was claimed to have a mass similar to that of Saturn and located in a 360-day orbit. Gregory cautioned that the close match between the period of this planet to being exactly a year meant that the radial velocity variations may have been caused by insufficient correction for the motion of the Earth in orbit around the Sun. The planet was not detected in re-reduced data in an analysis published in the Astrophysical Journal in 2009.

See also HD 11977 List of extrasolar planets

References

External links Extrasolar Planet Interactions Archived 2016-05-05 at the Wayback Machine by Rory Barnes & Richard Greenberg, Lunar and Planetary Lab, University of Arizona

Worked examples

Example 1 — a first encounter with HD 11964

Start with the simplest possible case. Write down what HD 11964 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 11964 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 11964 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 11964

In research: HD 11964 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 11964 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 11964 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Binary stars, Cetus (constellation), Durchmusterung objects, so understanding it makes those chapters shorter.
In everyday life: Look for HD 11964 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 “HD 11964” →

Affiliate

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

How to study HD 11964 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HD 11964 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 11964 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HD 11964 in simple terms?

Why does HD 11964 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 11964?

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 11964.