astronomy

Holmberg IX

Holmberg IX 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 Holmberg IX rather than just read about it. In short: Holmberg IX is a dwarf irregular galaxy and a satellite galaxy of M81, located in the constellation of Ursa Major. It is a Magellanic-type galaxy, similar to the Small Magellanic Cloud, neighbour galaxy to the Milky Way galaxy.

Key takeaways

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

Reference excerpt

Holmberg IX is a dwarf irregular galaxy and a satellite galaxy of M81, located in the constellation of Ursa Major. It is a Magellanic-type galaxy, similar to the Small Magellanic Cloud, neighbour galaxy to the Milky Way galaxy. The galaxy is named after Erik Holmberg who first described it, though it was originally discovered by Sidney van den Bergh in 1959. Based on the observed age distribution of stars it contains, 20% of its stellar mass formed within the last 200 Myr, making it the youngest nearby galaxy. It is also home to one of two yellow supergiant eclipsing binary systems designated Holmberg IX V1.

References

Further reading Winter, Lisa M.; Mushotzky, Richard F.; Reynolds, Christopher S. (2007). "Elemental Abundances of Nearby Galaxies through High Signal-to-Noise Ratio XMM-Newton Observations of Ultraluminous X-Ray Sources". The Astrophysical Journal. 655 (1): 163–178. arXiv:astro-ph/0610369. Bibcode:2007ApJ...655..163W. doi:10.1086/510200. S2CID 115819754. Fabien, Grisé; Pakull, Manfred W.; Motch, Christian (2006-05-12). "The Ultraluminous X-ray Source in Holmberg IX and its Environment". Proceedings of the International Astronomical Union. 1 (S230): 302–303. arXiv:astro-ph/0603768. Bibcode:2006IAUS..230..302G. doi:10.1017/S1743921306008519. S2CID 118995588. Makarova, L.; Grebel, E. K.; Karachentsev, I. D.; Dolphin, A. E.; Karachentseva, V. E.; Sharina, M. E.; Geisler, D.; Guhathakurta, P.; et al. (2002). "Tidal dwarfs in the M81 group: the second generation?". Astronomy and Astrophysics. 396 (2): 473–487. arXiv:astro-ph/0210235. Bibcode:2002A&A...396..473M. doi:10.1051/0004-6361:20021426. Schulte-Ladbeck, R. E.; Hopp, U. (1987). "The Dwarf Irregular Galaxy Holmberg IX". Mitteilungen der Astronomischen Gesellschaft. 70: 427. Bibcode:1987MitAG..70..427S. Bertola, F.; Maffei, P. (1974). "Two Faint Companions to M81". Astronomy and Astrophysics. 32: 117. Bibcode:1974A&A....32..117B. Holmberg, E. (1969). "A study of physical groups of galaxies". Arkiv för Astronomi. 5: 305–343. Bibcode:1969ArA.....5..305H. van den Bergh, Sidney (1959). "A catalogue of dwarf galaxies". Publications of the David Dunlap Observatory. 2 (5). University of Toronto: 147. Bibcode:1959PDDO....2..147V.

External links Media related to Holmberg IX at Wikimedia Commons M81's satellite galaxy Holmberg IX Holmberg IX: XMM1 GALEX Completes Four Star-Studded Years in Space Dwarf Galaxy Holmberg IX

Holmberg IX 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 Holmberg IX

Start with the simplest possible case. Write down what Holmberg IX 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 Holmberg IX 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 Holmberg IX 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 Holmberg IX

In research: Holmberg IX 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 Holmberg IX 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: Holmberg IX is common in secondary-school and first-year university syllabi. It links to neighbouring topics Dwarf irregular galaxies, Interacting galaxies, LEDA objects, so understanding it makes those chapters shorter.
In everyday life: Look for Holmberg IX 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 Holmberg IX in 20 minutes

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

Frequently asked questions

What is Holmberg IX in simple terms?

Why does Holmberg IX 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 Holmberg IX?

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 Holmberg IX.