astronomy

HD 109271

HD 109271 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 109271 rather than just read about it. In short: HD 109271 is a wide binary star system in the constellation of Virgo. The brighter member of the binary has a pair of orbiting exoplanets.

Key takeaways

HD 109271 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 109271 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HD 109271 from memory before moving on to harder problems.

Reference excerpt

HD 109271 is a wide binary star system in the constellation of Virgo. The brighter member of the binary has a pair of orbiting exoplanets. With an apparent visual magnitude of 8.05, it cannot be seen with the naked eye. Parallax measurements made by Gaia put the star at a distance of 181 light-years (55 parsecs) away from the Sun, but it is drifting closer with a radial velocity of −5 km/s. The system shows a high proper motion, traversing the celestial sphere at an angular rate of 0.232 arcsec yr−1. The primary component is an ordinary G-type main-sequence star with a stellar classification of G5 V. It is a much older star than the Sun with an age of about 7.3 billion years, and is spinning with a projected rotational velocity of 2.7 km/s. This star has 7% more mass than the Sun and a 30% greater girth. The abundance of iron, a measure of the star's metallicity, is similar but slightly higher than in the Sun. It is radiating 1.65 times the luminosity of the Sun from its photosphere at an effective temperature of around 5,783 K. In 2020, a white dwarf companion of 0.6 M☉ was found orbiting the primary at an angular separation of 5.4″ along a position angle of 267°. At the distance of this system, this corresponds to a projected separation of 304 AU. That is, they are physically separated by at least this distance. Additional stellar companions are ruled out down to a separation of 0.15″ from the primary.

Planetary system From 2003 to 2012, the star was under observance from the High Accuracy Radial Velocity Planet Searcher (HARPS). In 2012, two eccentric hot Neptune-mass planets were deduced by radial velocity. They were published in January 2013. These are close to a 1:4 resonance, so the system is similar to HD 69830. A third Neptune in the Venus zone was hypothesised from the data. These planets managed to survive the post main-sequence epoch of the companion star, when it shed much of its original mass.

References

Worked examples

Example 1 — a first encounter with HD 109271

Start with the simplest possible case. Write down what HD 109271 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 109271 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 109271 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 109271

In research: HD 109271 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 109271 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 109271 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Binary stars, Durchmusterung objects, G-type main-sequence stars, so understanding it makes those chapters shorter.
In everyday life: Look for HD 109271 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 109271” →

Affiliate

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

How to study HD 109271 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HD 109271 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 109271 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HD 109271 in simple terms?

HD 109271 is a wide binary star system in the constellation of Virgo. The brighter member of the binary has a pair of orbiting exoplanets.

Why does HD 109271 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 109271?

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 109271.