astronomy

HD 106315

HD 106315 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 106315 rather than just read about it. In short: HD 106315, or K2-109, is a single star with a pair of close-orbiting exoplanets, located in the constellation of Virgo. Based on parallax measurements, this system lies at a distance of 356 light years from the Sun.

Key takeaways

HD 106315 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 106315 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HD 106315 from memory before moving on to harder problems.

Reference excerpt

HD 106315, or K2-109, is a single star with a pair of close-orbiting exoplanets, located in the constellation of Virgo. Based on parallax measurements, this system lies at a distance of 356 light years from the Sun. At that range, the star is too faint to be seen with the naked eye, as it has an apparent visual magnitude of 8.95. But it is slowly drifting closer with a radial velocity of −3 km/s. As of 2020, multiplicity surveys have not detected any stellar companions to HD 106315. The spectrum of HD 106315 presents as an ordinary F-type main-sequence star with a stellar classification of F5V, indicating it is generating energy through hydrogen fusion at its core. It is estimated to be roughly four billion years old but is spinning quickly with a rotation period of 5 days. The star is relatively metal-poor, having 60% of solar concentration of iron. It has only a low level of magnetic activity in its chromosphere, showing a minimal level of star spot coverage. The star has 11% more mass and a 29% larger radius than the Sun. It is radiating 2.4 times the luminosity of the Sun from its photosphere at an effective temperature of 6,300 K.

Planetary system

Two planets were detected by the transit method in 2017, using data from the extended Kepler mission (K2). Their large planetary radii imply both planets have a massive steam atmosphere for planet b and hydrogen-helium atmosphere for planet c. The planetary system of HD 106315 is rather unstable and current planetary orbits are the outcome of violent dynamical history, strongly affected by relativistic effects. The orbits of planets are nearly coplanar, and orbit of c is well aligned with the equatorial plane of the star, misalignment been equal to -10+3.6−3.8°. Since 2017, a third outer planet with mass above 45M🜨 is suspected to exist in the system.

References

Worked examples

Example 1 — a first encounter with HD 106315

Start with the simplest possible case. Write down what HD 106315 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 106315 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 106315 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 106315

In research: HD 106315 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 106315 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 106315 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Durchmusterung objects, F-type main-sequence stars, Henry Draper Catalogue objects, so understanding it makes those chapters shorter.
In everyday life: Look for HD 106315 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 106315 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HD 106315 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 106315 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HD 106315 in simple terms?

Why does HD 106315 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 106315?

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 106315.