astronomy

IC 1613

IC 1613 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 IC 1613 rather than just read about it. In short: IC 1613 (also known as Caldwell 51) is an irregular dwarf galaxy located on the outskirts of the Local group around 730 kiloparsecs from Earth in the constellation of Cetus near the star 26 Ceti. It has a low mass with its mass only being around 108 solar masses.

Key takeaways

IC 1613 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect IC 1613 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of IC 1613 from memory before moving on to harder problems.

Reference excerpt

IC 1613 (also known as Caldwell 51) is an irregular dwarf galaxy located on the outskirts of the Local group around 730 kiloparsecs from Earth in the constellation of Cetus near the star 26 Ceti. It has a low mass with its mass only being around 108 solar masses. It has played an important role in the calibration of the Cepheid variable period-luminosity relation for estimating distances. Other than the Magellanic Clouds, it is one of the few Local Group dwarf irregular galaxy where RR Lyrae-type variables have been observed; this factor, along with an unusually low abundance of interstellar dust both within IC 1613 and along the line of sight enable especially accurate distance estimates. IC 1613 was discovered in 1906 by Max Wolf, and is approaching Earth at 234 km/s. There are many faint galaxies close to IC 1613, 14 of which are catalogued as members of a yet-unnamed galaxy cluster located at z≈0.20.

Stellar population

It is one of the few irregular dwarf galaxies in the Local group where RR Lyrae-type variable stars have been observed. Others include the Magellanic Clouds. In 1999, Cole et al. used the Hubble Space Telescope (HST) to find that the dominant population of this galaxy has an age of ~7 Gyr. Using its Hess diagram, they found that its evolutionary history may be similar to that of the Pegasus Dwarf Irregular Galaxy. Both galaxies are classified as Ir V in the DDO system. Also in 1999, Antonello et al. found five cepheids of Population II in IC 1613, giving self-evident support for the existence of a very old stellar population component of IC 1613. In 1999, King, Modjaz, & Li discovered the first nova ever detected in IC 1613. IC 1613 contains a WO star known as DR1, which might be the only Wolf–Rayet star in the galaxy, although a candidate WC+O binary, SPIRITS14bqe, has been found. A luminous blue variable candidate has been proposed but a revised classification led to a B2.5 III type. Moreover, a rich population of OB-type stars and OB associations has been discovered.

GHV-62024 is a O6-type star located in this galaxy that shows characteristics of F-type stars. It has a fast rotation which likely causes strong CNO mixing, the products of which contaminate the stars surface.

Supernova remnants

Many studies have studied the interstellar medium of IC 1613 such as H l and H ll complexes. There has currently been one recognized supernova remnant (SNR) which has been named S8. There may also be another remnant with a shell-like structure with a diameter of 55 parsecs. S8 was first identified by Allan Sandage as emission nebula no. 8 in 1971. He used the 200-inch Hale reflector. A study using data from the MDM Observatory found that S8 is a very young supernova remnant. The nebula has an estimated mass of 119±34 M☉ and an age between 2700 and 4400 years.

References

External links Media related to IC 1613 at Wikimedia Commons

IC 1613 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 IC 1613

Start with the simplest possible case. Write down what IC 1613 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 IC 1613 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 IC 1613 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 IC 1613

In research: IC 1613 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 IC 1613 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: IC 1613 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1906, Caldwell objects, Cetus (constellation), so understanding it makes those chapters shorter.
In everyday life: Look for IC 1613 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 IC 1613 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what IC 1613 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 IC 1613 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is IC 1613 in simple terms?

Why does IC 1613 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 IC 1613?

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 IC 1613.