astronomy

Gliese 205

Gliese 205 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 Gliese 205 rather than just read about it. In short: Gliese 205 is a nearby red dwarf star of spectral type M1.5, located in the constellation Orion at a distance of 18.6 light-years (5.7 parsecs) from Earth. History of observations A designation of this star, used in "Discovery Name" column of Table 4 of Kirkpatrick et al.

Key takeaways

Gliese 205 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Gliese 205 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Gliese 205 from memory before moving on to harder problems.

Reference excerpt

Gliese 205 is a nearby red dwarf star of spectral type M1.5, located in the constellation Orion at a distance of 18.6 light-years (5.7 parsecs) from Earth.

History of observations A designation of this star, used in "Discovery Name" column of Table 4 of Kirkpatrick et al. (2012), is Strb. 1611. This name was taken from van de Kamp (1930). The origin of this designation is not explained in these articles. Anyway, it is not Struve's 1827 catalogue of binary stars, since for this catalogue another prefix ("Σ") is used, for example, "Σ 2398", and real Σ 1611 is located in completely different part of the sky. Also, Gliese 205 is not a binary star. In the paper, published in Annales de l'Observatoire de Strasbourg in 1926 an object "N** Strasb. 1611" in "5h" sections was listed, so, possibly, this designation relates to the Observatory of Strasbourg. Possibly, it is the "Catalogue de Strasbourge" of 8204 stars, published in Volume 4 of Annales de l'Observatoire de Strasbourg in 1912 — a part of international Astronomische Gesellschaft Katalog (AGK), made by various observatories by 1912. If so, then there are earlier designations). Of the other designations, the earliest one is W. B. V. 592 or Weisse I, 5h 592 (Maximiliano Weisse; Friedrich Bessel, Positiones mediae stellarum fixarum I, 1846). This catalogue was based on observations, made by Bessel in 1821–1833 and published in 1822–1838 in Astronomische Beobachtungen auf der königlichen Universitäts-Sternwarte in Königsberg as "Beobachtungen der Sterne, nach Zonen der Abweichung angestellt". Gliese 205, probably, was observed on January 8, 1823 in zone 140 (see the 9th abtheilung (1824), page 55, 2nd column, 33rd string).

Search for planets In a 2019 preprint, two candidate planets were detected using the radial velocity method, both Neptune-mass with orbital periods of 17 and 270 days. However, a study of this star in 2023 found no evidence of planets, and determined a stellar rotation period of 34.4 days.

References

Worked examples

Example 1 — a first encounter with Gliese 205

Start with the simplest possible case. Write down what Gliese 205 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 Gliese 205 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 Gliese 205 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 Gliese 205

In research: Gliese 205 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 Gliese 205 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: Gliese 205 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Durchmusterung objects, Gliese and GJ objects, Henry Draper Catalogue objects, so understanding it makes those chapters shorter.
In everyday life: Look for Gliese 205 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 Gliese 205 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Gliese 205 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 Gliese 205 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Gliese 205 in simple terms?

Gliese 205 is a nearby red dwarf star of spectral type M1.5, located in the constellation Orion at a distance of 18.6 light-years (5.7 parsecs) from Earth. History of observations A designation of this star, used in "Discovery Name" column of Table 4 of Kirkpatrick et al.

Why does Gliese 205 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 Gliese 205?

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 Gliese 205.