astronomy

OGC 139

OGC 139 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 OGC 139 rather than just read about it. In short: OGC 139 also known as 2MASX J16394598+4609058 is a massive spiral galaxy located in the constellation of Hercules. The redshift of the galaxy is (z) 0.247 and it is classified as a super spiral galaxy; a type of massive disk galaxy considered to be star-forming.

Key takeaways

OGC 139 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect OGC 139 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of OGC 139 from memory before moving on to harder problems.

Reference excerpt

OGC 139 also known as 2MASX J16394598+4609058 is a massive spiral galaxy located in the constellation of Hercules. The redshift of the galaxy is (z) 0.247 and it is classified as a super spiral galaxy; a type of massive disk galaxy considered to be star-forming.

Description OGC 139 is categorized as an edge-on spiral galaxy. The isophotal diameter of the galaxy is estimated to be 134 kiloparsecs and it has an apparent luminosity of Lr = 12.0. The bulge fraction ratio is calculated to be B/T = 0.13, with the galactic disk having an inclination of 76° and orientated at the position angle of 28°. The scale of the disk is 3.88 kiloparsecs, with the disk exponential scale of Rd = 32.98. The total star formation rate of OGC 139 is 1.65 M☉ per year based on the calculation of the 12 micrometer band by Wide-field Infrared Survey Explorer (WISE). The mass of the stars is calculated to be 11.74 M☉ based on a W1-band luminosity with the gas mass of 10.9 M☉ based on the total star formation rate. A study published in 2021 found the inclination of the galaxy is 76° based on the z-band axial ratio with the major axis position angle found to be 115°. The maximum deprojected speed of the galaxy is found to be vmax = 483 kilometers per seconds at 90 kiloparsecs based on both standard deviation and the hydrogen-alpha rotation curve measurements.

References

External links OGC 139 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

Illustrations

Worked examples

Example 1 — a first encounter with OGC 139

Start with the simplest possible case. Write down what OGC 139 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 OGC 139 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 OGC 139 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 OGC 139

In research: OGC 139 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 OGC 139 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: OGC 139 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Hercules (constellation), LEDA objects, SDSS objects, so understanding it makes those chapters shorter.
In everyday life: Look for OGC 139 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 OGC 139 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what OGC 139 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 OGC 139 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is OGC 139 in simple terms?

Why does OGC 139 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 OGC 139?

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 OGC 139.