astronomy

Psi1 Draconis

Psi1 Draconis 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 Psi1 Draconis rather than just read about it. In short: Psi1 Draconis (ψ1 Draconis, abbreviated Psi1 Dra, ψ1 Dra), also designated 31 Draconis, is a triple star system in the northern constellation of Draco. The system is fairly close, and is located about 75 light-years (23 parsecs) from the Sun, based on its parallax.

Key takeaways

Psi1 Draconis belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Psi1 Draconis to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Psi1 Draconis from memory before moving on to harder problems.

Reference excerpt

Psi1 Draconis (ψ1 Draconis, abbreviated Psi1 Dra, ψ1 Dra), also designated 31 Draconis, is a triple star system in the northern constellation of Draco. The system is fairly close, and is located about 75 light-years (23 parsecs) from the Sun, based on its parallax. Psi1 Draconis was considered a binary star consisting of an F-type subgiant and an F-type main-sequence star, designated Psi1 Draconis A (officially named Dziban , from the traditional name of the system) and Psi1 Draconis B, respectively. In 2015, Psi1 Draconis A was itself found to be a double-lined spectroscopic binary, making the system a triple. The companion to Psi1 Draconis A was designated Psi1 Draconis C by its discoverers. Also in 2015, Psi1 Draconis B was discovered to be orbited by an exoplanet, designated Psi1 Draconis Bb.

Nomenclature

ψ1 Draconis (Latinised to Psi1 Draconis) is the system's Bayer designation and 31 Draconis its Flamsteed designation. The designation of the components – ψ1 Draconis A and B – derives from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU). Psi1 Draconis bore the traditional name of Dziban or Dsiban, derived from the Arabic Adh-Dhi'ban, meaning "The two wolves" or "The two jackals". In 2016, the IAU organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems. It approved the name Dziban for the component Psi1 Draconis A on 5 September 2017 and it is now so included in the List of IAU-approved Star Names. In Chinese astronomy, Psi1 Draconis is called 女史, Pinyin: Nǚshǐ, meaning Female Protocol, because this star is marking itself and stands alone in the asterism Female Protocol in the Purple Forbidden enclosure (see Chinese constellation). 女史 (Nǚshǐ) has been Latinised into Niu She by R.H. Allen, meaning "the Palace Governess", or "a Literary Woman".

Properties ψ1 Draconis AC and ψ1 Draconis B are separated by about 31 arcseconds. Only a very small fraction of the orbit has been observed: an orbital period of 10,000 years has been calculated, but it is extremely preliminary and likely to be in high error. ψ1 Draconis A and C have varying radial velocities in respect to Earth, indicating that there must be orbital motion. The orbital period is estimated to be around 20 years, and the eccentricity must be fairly high, around 0.679.

Planetary system Psi1 Draconis Bb is a Jupiter-like exoplanet orbiting Psi1 Draconis B, the secondary star. The planet was discovered when periodic Doppler shifts in the star's spectrum revealed the presence of a planet, similar to the spectroscopic binary nature of Psi1 Draconis AC. Its minimum mass is 1.53 MJ, and it orbits its host star every 8.5 years taking a relatively eccentric orbit.

References

Illustrations

Worked examples

Example 1 — a first encounter with Psi1 Draconis

Start with the simplest possible case. Write down what Psi1 Draconis 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 Psi1 Draconis 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 Psi1 Draconis 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 Psi1 Draconis

In research: Psi1 Draconis 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 Psi1 Draconis 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: Psi1 Draconis is common in secondary-school and first-year university syllabi. It links to neighbouring topics Bayer objects, Bright Star Catalogue objects, Draco (constellation), so understanding it makes those chapters shorter.
In everyday life: Look for Psi1 Draconis 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 Psi1 Draconis in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Psi1 Draconis 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 Psi1 Draconis out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Psi1 Draconis in simple terms?

Why does Psi1 Draconis 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 Psi1 Draconis?

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 Psi1 Draconis.