astronomy

V1054 Ophiuchi

V1054 Ophiuchi 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 V1054 Ophiuchi rather than just read about it. In short: V1054 Ophiuchi, together with the star Gliese 643, is a nearby quintuple star system, located in the constellation Ophiuchus at a distance of 21.2 light-years (6.5 parsecs). It consists of five stars, all of which are red dwarfs.

Key takeaways

V1054 Ophiuchi belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect V1054 Ophiuchi to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of V1054 Ophiuchi from memory before moving on to harder problems.

Reference excerpt

V1054 Ophiuchi, together with the star Gliese 643, is a nearby quintuple star system, located in the constellation Ophiuchus at a distance of 21.2 light-years (6.5 parsecs). It consists of five stars, all of which are red dwarfs. The alternative designation of Wolf 630 forms the namesake of a moving group of stars that share a similar motion through space.

Overview

V1054 Ophiuchi/Gliese 643 is the nearest quintuple star system; the next nearest star systems with at least five stars are Xi Ursae Majoris (quintuple, including a brown dwarf) at 28.5 light-years, Castor (sextuple) at 49.2 light-years, and GJ 2069 (quintuple) at 54.3 light-years. V1054 Ophiuchi and Xi Ursae Majoris are the only two quintuple star systems within 10 parsecs. The system consists of three widely separated parts:

close triple subsystem V1054 Ophiuchi A-Bab (including very close binary subsystem V1054 Ophiuchi Bab) Gliese 643 V1054 Ophiuchi C (vB 8) The brightest and most massive of these five stars is V1054 Ophiuchi A. The close binary subsystem V1054 Ophiuchi B is more massive than V1054 Ophiuchi A, however, its total visual magnitude is 0.1 mag fainter than V1054 Ophiuchi A's visual magnitude. The total apparent magnitude of the V1054 Ophiuchi A-Bab triple subsystem is 9.02. Despite V1054 Ophiuchi/Gliese 643 consisting of low-mass stars, the system's total mass, due to the large number of components, exceeds the Solar mass, about 1.35 M☉.

Distance Currently, the most accurate distance estimate of V1054 Ophiuchi/Gliese 643 is a trigonometric parallax of Gliese 643 from Gaia DR3: 153.8754±0.0474 mas, corresponding to a distance of 6.499±0.002 pc, or 21.196±0.007 ly. Past V1054 Ophiuchi/Gliese 643 distance estimates V1054 Ophiuchi A-Bab:

Gliese 643:

V1054 Ophiuchi C (vB 8):

Weighted mean distance A weighted mean parallax was calculated by RECONS in 2012, considering YPC (V1054 Ophiuchi A-Bab and Gliese 643), Hipparcos (Soederhjelm — V1054 Ophiuchi A-Bab and van Leeuwen — Gliese 643) and CTIOPI (V1054 Ophiuchi C) data. The value is 154.96±0.52 mas, corresponding to a distance of 6.453±0.022 pc, or 21.05±0.07 ly. This predates Gaia astrometry of the system.

System

V1054 Ophiuchi A-Bab (inner triple subsystem) V1054 Ophiuchi A-Bab is a close spectroscopic triple subsystem, consisting of the brighter component V1054 Ophiuchi A and the more massive binary subsystem V1054 Ophiuchi Bab, orbiting each other with a period of 627 days, or 1.72 years. V1054 Ophiuchi Bab components are orbiting each other with a period of 2.9655 days. Both outer and inner orbits are nearly circular and, probably, coplanar (in keeping with a general tendency of close triple systems). V1054 Ophiuchi A-Bab pair is also visually resolved (for nearly 50 years it was the shortest-period resolved by visual means binary, since its binarity was discovered by G. P. Kuiper in 1934), whereas V1054 Ophiuchi Ba-Bb pair is still unresolved).

Gliese 643 The projected separation of Gliese 643 from V1054 Ophiuchi A-Bab is 72 arcsec, corresponding at 21.05 light-years to 465 AU.

V1054 Ophiuchi C (vB 8) vB 8 is the smallest, faintest, and most separated component of the V1054 Ophiuchi system. The projected separation of the red dwarf from the primary triple system is about 220 arcsec, corresponding at 21.05 light-years to 1420 a.u. Since it is only three times larger than the projected separation between Gliese 643 and V1054 Ophiuchi A-Bab, and such a small ratio should render the triple system dynamically unstable, it was suggested that the real separation of V1054 Ophiuchi C from V1054 Ophiuchi A-Bab is much larger, at least by a factor of two, i. e. at least 2840 a.u. In 1984, the apparent detection of an infrared source near vB 8 suggested it had a low mass companion. The low mass of this candidate led to speculation that it may be a brown dwarf; the first such to be detected. This discovery was later found to be spurious, but it produced much interest in this class of astronomical object.

Notes

References

Illustrations

Worked examples

Example 1 — a first encounter with V1054 Ophiuchi

Start with the simplest possible case. Write down what V1054 Ophiuchi 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 V1054 Ophiuchi 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 V1054 Ophiuchi 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 V1054 Ophiuchi

In research: V1054 Ophiuchi 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 V1054 Ophiuchi 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: V1054 Ophiuchi 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 V1054 Ophiuchi 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 V1054 Ophiuchi in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what V1054 Ophiuchi 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 V1054 Ophiuchi out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is V1054 Ophiuchi in simple terms?

Why does V1054 Ophiuchi 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 V1054 Ophiuchi?

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 V1054 Ophiuchi.