astronomy

HD 149026

HD 149026 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 149026 rather than just read about it. In short: HD 149026, also named Ogma , is a yellow subgiant star approximately 249 light-years from the Sun in the constellation of Hercules. An exoplanet (designated HD 149026 b, later named Smertrios) orbits the star.

Key takeaways

HD 149026 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 149026 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HD 149026 from memory before moving on to harder problems.

Reference excerpt

HD 149026, also named Ogma , is a yellow subgiant star approximately 249 light-years from the Sun in the constellation of Hercules. An exoplanet (designated HD 149026 b, later named Smertrios) orbits the star.

Nomenclature HD 149026 is the star's identifier in the Henry Draper Catalog. Following its discovery in 2005 the planet was designated HD 149026 b. In July 2014 the International Astronomical Union (IAU) launched NameExoWorlds, a process for giving proper names to certain exoplanets and their host stars. The process involved public nomination and voting for the new names. In December 2015, the IAU announced the winning names were Ogma for this star and Smertrios for its planet. The winning names based on those submitted by the Club d'Astronomie de Toussaint of France; namely 'Ogmios' and 'Smertrios'. Ogmios was a Gallo-Roman deity and Smertrios was a Gallic deity of war. The IAU substituted the name of Ogma, a deity of eloquence, writing, and great physical strength in the Celtic mythologies of Ireland and Scotland, and who may be related to Ogmios, because 'Ogmios' is the name of an asteroid (189011 Ogmios). In 2016, the IAU organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. In its first bulletin of July 2016, the WGSN explicitly recognized the names of exoplanets and their host stars approved by the Executive Committee Working Group Public Naming of Planets and Planetary Satellites, including the names of stars adopted during the 2015 NameExoWorlds campaign. This star is now so entered in the IAU Catalog of Star Names.

Properties The star is thought to be more massive, larger, and brighter than the Sun. The higher mass means that despite its considerably younger age (2.0 Ga) it is already much more evolved than the Sun. The internal fusion of hydrogen in the core of the star is about at an end and the star is cooling towards red gianthood. At a distance of 249 light-years, the star is not visible to the unaided eye. However, it should be easily seen in binoculars or a small telescope. The star is over twice as enriched with chemical elements heavier than hydrogen and helium as the Sun. Because of this and the fact that the star is relatively bright, a group of astronomers in N2K Consortium began to study the star. The star's anomalous composition as measured may be surface pollution only, from the intake of heavy-element planetesimals.

Planetary system In 2005 an unusual extrasolar planet was discovered to be orbiting the star. Designated HD 149026 b, it was detected transiting the star allowing its diameter to be measured. It was found to be smaller than other transiting planets known at the time, meaning it is unusually dense for a closely orbiting giant planet. In 2007, the temperature of the giant planet was calculated to be 2,300 K (2,030 °C; 3,680 °F), generating so much infrared heat that it glows. It was proposed that the planet absorbs nearly all the sunlight and radiates it into space as heat. Subsequent studies have not confirmed this, with a 2018 study finding the planet to be highly reflective (with a Bond albedo of 0.53), along with a lower temperature.

Illustrations

Worked examples

Example 1 — a first encounter with HD 149026

Start with the simplest possible case. Write down what HD 149026 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 149026 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 149026 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 149026

In research: HD 149026 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 149026 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 149026 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 149026 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 149026 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HD 149026 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 149026 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HD 149026 in simple terms?

Why does HD 149026 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 149026?

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 149026.