astronomy

PZ Telescopii

PZ Telescopii 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 PZ Telescopii rather than just read about it. In short: PZ Telescopii, also known as HD 174429 or simply PZ Tel, is a young star in the constellation Telescopium. Based on parallax measurements, it is located at a distance of 154 light-years from the Sun.

Key takeaways

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

Reference excerpt

PZ Telescopii, also known as HD 174429 or simply PZ Tel, is a young star in the constellation Telescopium. Based on parallax measurements, it is located at a distance of 154 light-years from the Sun. It is too faint to be visible to the naked eye, yet it is one of the closest and hence brightest pre-main-sequence stars to Earth. In 1980, Denis Walter Coates et al. announced that the star, then known as HD 174429, is a variable star. It was given its variable star designation, PZ Telescopii, in 1981. It is classified as a BY Draconis variable that ranges in apparent visual magnitude from 8.33 down to 8.63 over a period of 22.581 hours (0.94088 days). PZ Telescopii has an effective surface temperature of around 5,338 K (the Sun has an approximate surface temperature of 5,778 K), a mass around 1.13 times, and diameter 1.23 times that of the Sun. The star has a high rate of spin, showing a projected rotational velocity of 69 km/s and a rotation period of 22.6 h. It is radiating about the same luminosity as the Sun. PZ Telescopii was originally considered to be a member of the Beta Pictoris moving group; however in a 2012 paper, James Jenkins of Universidad de Chile and colleagues used three methods to calculate its age and came up with a figure of around 24 million years—significantly older than the 12 million years of the association. This star has an orbiting debris disk calculated to span from a radius of 35 to 165 astronomical units (AU), as well as a substellar companion with about 28 or 36 times the mass of Jupiter orbiting at a distance of about 16 AU, discovered in 2009 independently by two teams. The companion, currently known as PZ Tel B, is thought to be a brown dwarf; however it is possible (though very unlikely) that it is an extremely large Jupiter-like planet, in which case it would be PZ Tel b, and the first such planet to be directly imaged. Preliminary orbital elements from 2016 give a best fit orbital period of 622.2 years with an eccentricity of 0.755. The mass and orbit of this companion were updated in 2023 based on Hipparcos and Gaia astrometry, finding a somewhat lower mass, and an edge-on orbit that is eccentric but less so than previous results. It is now included in the NASA Exoplanet Archive since its nominal mass of 27 MJ is below their upper limit of 30 MJ, although the margin of error is large enough that it is still possible that the mass exceeds 30 MJ. Updated values were provided in 2026, providing tighter constraints in the mass and orbit of PZ Telescopii b.

References

External links Watson, Christopher (19 April 2012). "PZ Telescopii". AAVSO Website. American Association of Variable Star Observers. Retrieved 1 July 2014.

Illustrations

Worked examples

Example 1 — a first encounter with PZ Telescopii

Start with the simplest possible case. Write down what PZ Telescopii 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 PZ Telescopii 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 PZ Telescopii 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 PZ Telescopii

In research: PZ Telescopii 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 PZ Telescopii 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: PZ Telescopii is common in secondary-school and first-year university syllabi. It links to neighbouring topics BY Draconis variables, Brown dwarfs, Circumstellar disks, so understanding it makes those chapters shorter.
In everyday life: Look for PZ Telescopii 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 PZ Telescopii in 20 minutes

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

Frequently asked questions

What is PZ Telescopii in simple terms?

PZ Telescopii, also known as HD 174429 or simply PZ Tel, is a young star in the constellation Telescopium. Based on parallax measurements, it is located at a distance of 154 light-years from the Sun.

Why does PZ Telescopii 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 PZ Telescopii?

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 PZ Telescopii.