astronomy

HD 93396

HD 93396 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 93396 rather than just read about it. In short: HD 93396 (HIP 52733; TOI-664; KELT-11) is a star located in the equatorial constellation Sextans. It has an apparent magnitude of 8.04, making it readily visible in binoculars, but not to the naked eye.

Key takeaways

HD 93396 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 93396 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HD 93396 from memory before moving on to harder problems.

Reference excerpt

HD 93396 (HIP 52733; TOI-664; KELT-11) is a star located in the equatorial constellation Sextans. It has an apparent magnitude of 8.04, making it readily visible in binoculars, but not to the naked eye. The object is located relatively close at a distance of 326 light-years based on Gaia DR3 parallax measurements, but it is receding with a heliocentric radial velocity of 34.96 km/s. At its current distance, HD 93396's brightness is diminished by an interstellar extinction of 0.17 magnitudes and it has an absolute magnitude of +3.01. HD 93396 has a stellar classification of G8/K0 IV, indicating that it is an evolved star with the characteristics of a G8 and K0 subgiant. At the age of 3.48 billion years, it is currently in the Hertzsprung gap, meaning that the star is in the process of ceasing hydrogen fusion at its stellar core and it is evolving towards the red giant branch. It has 1.43 times the mass of the Sun and a slightly enlarged radius 2.93 times that of the Sun's. It radiates 6.01 times the luminosity of the Sun from its photosphere at an effective temperature of 5,375 K, giving it a yellowish-orange hue when viewed in the night sky. Like many planetary hosts, HD 93396 is metal enriched, having an iron abundance of [Fe/H] = +0.17 or 148% that of the Sun's. It spins slowly with a projected rotational velocity of 1.8 km/s. HD 93396 has a proper motion companion, a K-dwarf star with 0.69 times the mass of the Sun. It has an angular separation of 1,266 arcseconds (0.35 degrees) from its primary across a position angle of 100°. At the system's distance, this separation translates to a physical projected separation of 126,500 astronomical units (2.0 ly; 0.61 pc).

Planetary system In 2017, a sub-Saturn exoplanet was discovered transiting the star using the Kilodegree Extremely Little Telescope. It orbits very close to the star within a period of 4 days. Although the planet only has 17% the mass of Jupiter, it is 35% larger than the jovian planet, making it one of the most inflated and least dense exoplanets. Subsequent observations revealed that the planet's atmosphere contains water vapor and a high abundance of titanium and aluminum oxides.

References

Worked examples

Example 1 — a first encounter with HD 93396

Start with the simplest possible case. Write down what HD 93396 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 93396 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 93396 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 93396

In research: HD 93396 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 93396 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 93396 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Durchmusterung objects, G-type subgiants, Henry Draper Catalogue objects, so understanding it makes those chapters shorter.
In everyday life: Look for HD 93396 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.

Affiliate

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

How to study HD 93396 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HD 93396 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 93396 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HD 93396 in simple terms?

Why does HD 93396 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 93396?

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 93396.