astronomy

HD 102195

HD 102195 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 102195 rather than just read about it. In short: HD 102195 is an orange-hued star in the zodiac constellation of Virgo with a confirmed exoplanet companion. With an apparent visual magnitude of 8.07, the star is too faint to be seen with the naked eye.

Key takeaways

HD 102195 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 102195 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HD 102195 from memory before moving on to harder problems.

Reference excerpt

HD 102195 is an orange-hued star in the zodiac constellation of Virgo with a confirmed exoplanet companion. With an apparent visual magnitude of 8.07, the star is too faint to be seen with the naked eye. The distance to HD 102195 can be estimated from its annual parallax shift of 34.06 mas, yielding 95.8 light years. It is moving further away from the Earth with a heliocentric radial velocity of 1.89 km/s. This is a high proper motion star and a possible member of the η Cha stellar kinematic group. The star HD 102195 is named Flegetonte. The name was selected in the NameExoWorlds campaign by Italy, during the 100th anniversary of the IAU. Flegetonte is the underworld river of fire from Greek mythology in the Italian narrative poem on the afterlife Divina Commedia. This K-type main-sequence star has a stellar classification of K0 V. It is a quasi-periodic variable star with a cycle of 11.5 days, a variation range of 3.65%, and a phased amplitude of 94%. HD 102195 is around six billion years old with a rotation period of 12.3 days. It has 88% of the Sun's mass and 84% of the Sun's radius. It is radiating 49% of the Sun's luminosity from its photosphere at an effective temperature of 5,283 K. In 2005, an orbiting companion was detected using the Exoplanet Tracker instrument. This near Jupiter-mass exoplanet has an orbital period of 4.1 days with a circular orbit. By comparing the rotation period and radius of the star with the projected rotational velocity, Melo et al. (2007) derived an orbital inclination of 47°. This would suggest a planetary mass of 0.62 MJ.

Worked examples

Example 1 — a first encounter with HD 102195

Start with the simplest possible case. Write down what HD 102195 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 102195 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 102195 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 102195

In research: HD 102195 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 102195 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 102195 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Durchmusterung objects, Henry Draper Catalogue objects, Hipparcos objects, so understanding it makes those chapters shorter.
In everyday life: Look for HD 102195 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 102195 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HD 102195 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 102195 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HD 102195 in simple terms?

Why does HD 102195 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 102195?

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 102195.