astronomy

Iota Horologii b

Iota Horologii b 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 Iota Horologii b rather than just read about it. In short: Iota Horologii b (ι Hor b / ι Horologii b), often catalogued HR 810 b, is an extrasolar planet approximately 56.5 light-years away in the constellation of Horologium (the Pendulum Clock). Iota Horologii b has a minimum mass 2.26 times that of Jupiter; astrometric measurements from Gaia suggest it has a true mass of 6.2 MJ.

Key takeaways

Iota Horologii b belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Iota Horologii b to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Iota Horologii b from memory before moving on to harder problems.

Reference excerpt

Iota Horologii b (ι Hor b / ι Horologii b), often catalogued HR 810 b, is an extrasolar planet approximately 56.5 light-years away in the constellation of Horologium (the Pendulum Clock). Iota Horologii b has a minimum mass 2.26 times that of Jupiter; astrometric measurements from Gaia suggest it has a true mass of 6.2 MJ.

Detection and discovery The discovery of Iota Horologii b was the result of a long-term survey of forty Solar analog stars that was begun in November 1992. The planet represents the first discovery of an extrasolar planet with a European Southern Observatory instrument, with the data found at the La Silla Observatory in Chile. The Keplerian signal found the planet to have an orbital period of 320.1 days, indicative of an orbiting planet with minimum mass of 2.26 Jupiter masses. Iota Horologii b was announced in the summer of 1999 as the first planet found by a team of planet hunters led by Martin Kürster. The measurements of Iota Horologii show that the planet orbits the star approximately every 320 days. From this period, the known mass of the central star (1.25 solar masses) and the amplitude of the velocity changes, a mass of at least 2.26 times that of planet Jupiter is deduced for the planet. It revolves around the host star in a somewhat elongated orbit. If it were located in the Solar System, this orbit would stretch from just outside the orbit of Venus (at 117 million km or 0.78 astronomical units [AU] from the Sun) to just outside the orbit of the Earth (at 162 million km or 1.08 AU). Because the planet is about 2,000 times more massive than the Earth, it is predicted that Iota Horologii b is more similar to planet Jupiter. Preliminary astrometric analysis of Iota Horologii b suggested that planet b may have as much as 24 times the mass of Jupiter with an inclination of 5.5 degrees from Earth's line of sight. With these calculations, Iota Horologii b may actually be an extremely dim brown dwarf and a substellar companion of Iota Horologii. However, these measurements were later proved useful only for upper limits of inclination. An astrometric measurement of the planet's inclination and true mass was published in 2022 as part of Gaia DR3, revealing it to have a planetary mass of 6.2 MJ.

See also List of exoplanets discovered before 2000

References

External links "Iota Horologii". SolStation. Retrieved 2008-06-12.{{cite web}}: CS1 maint: deprecated archival service (link) "The Planet Around HD17051". California & Carnegie Planet Search Team. 2003-05-04. Archived from the original on 2008-05-18. Retrieved 2008-06-12.

Illustrations

Worked examples

Example 1 — a first encounter with Iota Horologii b

Start with the simplest possible case. Write down what Iota Horologii b 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 Iota Horologii b 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 Iota Horologii b 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 Iota Horologii b

In research: Iota Horologii b 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 Iota Horologii b 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: Iota Horologii b is common in secondary-school and first-year university syllabi. It links to neighbouring topics Exoplanets detected by astrometry, Exoplanets detected by radial velocity, Exoplanets discovered in 1999, so understanding it makes those chapters shorter.
In everyday life: Look for Iota Horologii b 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 Iota Horologii b in 20 minutes

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

Frequently asked questions

What is Iota Horologii b in simple terms?

Why does Iota Horologii b 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 Iota Horologii b?

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 Iota Horologii b.