astronomy

Groombridge 1830

Groombridge 1830 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 Groombridge 1830 rather than just read about it. In short: Groombridge 1830, also known as Argelander's Star, is a star 29.9 light-years away in the constellation Ursa Major. With an apparent magnitude of 6.4, it is near the limit of naked eye visibility under ideal conditions.

Key takeaways

Groombridge 1830 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Groombridge 1830 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Groombridge 1830 from memory before moving on to harder problems.

Reference excerpt

Groombridge 1830, also known as Argelander's Star, is a star 29.9 light-years away in the constellation Ursa Major. With an apparent magnitude of 6.4, it is near the limit of naked eye visibility under ideal conditions. It has a low metallicity and is thought to be a superflare star.

Discovery and naming The star was catalogued by British astronomer Stephen Groombridge with the Groombridge Transit Circle between 1806 and the 1830s and published posthumously in his star catalog, Catalogue of Circumpolar Stars (1838). The designation Groombridge 1830 comes from this catalog; in older sources it may be written as 1830 Groombridge. Its high proper motion was noted by Friedrich Wilhelm Argelander in 1842, and so it is sometimes called Argelander's Star, a name first used in an 1853 paper. Due to its high proper motion, it has also been called the Flying Star or Runaway Star (compare 61 Cygni and Barnard's Star). Other designations for this star include HD 103095, HR 4550, and Gliese 451. It has the variable star designation CF Ursae Majoris, which originally referred to a supposed flaring companion star that is no longer believed to exist.

Description Groombridge 1830 has been variously classified as a K-type main-sequence star, a G-type main-sequence star, or a G-type subdwarf. The low metallicity of this star makes some of its spectral lines resemble those of a G-class star, and it has been given as a spectral standard for the class G7V. It is 29.9 light-years (9.2 parsecs) from the Sun as measured by the Gaia spacecraft, which, as the distance is nearly 10 parsecs, means its absolute magnitude is almost equal to its apparent magnitude. It is a member of the galactic halo; such stars account for only 0.1 to 0.2 percent of the stars near the Sun. Like most halo stars, it has a low abundance of elements other than hydrogen and helium—what astronomers term a metal-poor star. Once suspected to be a binary star with a red dwarf flare star companion, the current consensus is that it is single. Previous observations of stellar flares, suspected to be from a companion star, were probably "superflares" on the primary star—analogous to the Sun's solar flares, but hundreds to millions of times more energetic. It was one of the first nine identified superflare stars.

Proper motion When discovered, Groombridge 1830 had the highest known proper motion of any star, replacing 61 Cygni. Kapteyn's Star and Barnard's Star have since been identified as having even higher proper motions. It is considerably farther away than either of those stars, however, which means its transverse velocity is greater.

See also List of star systems within 25–30 light-years

References

Further reading Israelian, Garik; García López, Ramon J.; Rebolo, Rafael (1998). "Oxygen Abundances in Unevolved Metal-poor Stars from Near-Ultraviolet OH Lines". Astrophysical Journal. 507 (2): 805–817. arXiv:astro-ph/9806235. Bibcode:1998ApJ...507..805I. doi:10.1086/306351. S2CID 18215356. Petersen, A. C. (1843). "Beobachtungen des Cometen auf der Altonaer Sternwarte. Von Herrn Observator Ritter Petersen". Astronomische Nachrichten (in German). 20 (10): 163. Bibcode:1843AN.....20..163P. doi:10.1002/asna.18430201003. Jürgensen, Louis Urban (1843). "L'Idée de parvenir à l'isochronisme des vibrations du pendule à l'aide du ressort auquel le pendule estsuspendu, est concue par Urbain-Jürgensen, et émise dans le numéro 49 des Astr. Nachr. 1823 Par Mr. Louis Urbain Jürgensen". Astronomische Nachrichten (in French). 20: 279. Bibcode:1843AN.....20..279J. doi:10.1002/asna.18430201703.

Illustrations

Worked examples

Example 1 — a first encounter with Groombridge 1830

Start with the simplest possible case. Write down what Groombridge 1830 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 Groombridge 1830 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 Groombridge 1830 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 Groombridge 1830

In research: Groombridge 1830 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 Groombridge 1830 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: Groombridge 1830 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Bright Star Catalogue objects, Durchmusterung objects, Gliese and GJ objects, so understanding it makes those chapters shorter.
In everyday life: Look for Groombridge 1830 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 Groombridge 1830 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Groombridge 1830 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 Groombridge 1830 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Groombridge 1830 in simple terms?

Why does Groombridge 1830 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 Groombridge 1830?

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 Groombridge 1830.