astronomy

PSR B1620−26

PSR B1620−26 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 PSR B1620−26 rather than just read about it. In short: PSR B1620−26 is a binary star system located at a distance of 3,800 parsecs (12,400 light-years) in the globular cluster of Messier 4 (M4, NGC 6121) in the constellation of Scorpius. The system is composed of a pulsar (PSR B1620−26 A) and a white dwarf star (WD B1620−26, or PSR B1620−26 B).

Key takeaways

PSR B1620−26 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect PSR B1620−26 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of PSR B1620−26 from memory before moving on to harder problems.

Reference excerpt

PSR B1620−26 is a binary star system located at a distance of 3,800 parsecs (12,400 light-years) in the globular cluster of Messier 4 (M4, NGC 6121) in the constellation of Scorpius. The system is composed of a pulsar (PSR B1620−26 A) and a white dwarf star (WD B1620−26, or PSR B1620−26 B). As of 2000, the system is also confirmed to have an exoplanet orbiting the two stars.

History The double system (triple including the substellar companion) is just outside the core of the globular cluster. The age of the cluster has been estimated to be about 12.2 billion years. Hence this is the age estimate for the birth of the planet, and two stars. There is a minor dispute about the proper nomenclature rules to use for this unusual star system. One side regards the A/B convention of naming binary stars as having priority, so that the pulsar is PSR B1620−26 A, the white dwarf companion is PSR B1620−26 B and the planet is PSR B1620−26 c. The other side considers PSR to apply only to stars which are pulsars, not their companions, so the white dwarf should be named using the WD convention, making the pulsar PSR B1620−26, the white dwarf "WD J1623−266", and the planet "PSR B1620−26 b." Early articles used the first convention, but star catalogs have been using the second. The most recent proposal provides a nomenclature like PSR B1620−26 (AB)b, including capital letters A and B in parentheses to identify inner stellar components of binary system, followed by italic letter b referred to outer planetary companion. In practice, context makes it clear whether the pulsar, the white dwarf, the planet, or the system as a whole is being referred to.

White dwarf The mass of the white dwarf is 0.34 solar masses and orbits at a period of 191 days with an inclination of 55° relative to its pulsar companion. Its age is approximately (480±140)×106 years.

Planetary system

PSR B1620−26 b was originally detected through the Doppler shifts its orbit induces on signals from the star it orbits (in this case, changes in the apparent pulsation period of the pulsar). In the early 1990s, a group of astronomers led by Donald Backer, studying what they thought was a binary pulsar, determined that a third object was needed to explain the observed Doppler shifts. Within a few years, the gravitational effects of the planet on the orbit of the pulsar and white dwarf had been measured, giving an estimate of the mass of the third object that was too small for it to be a star. The conclusion that the third object was a planet was announced by Stephen Thorsett and his collaborators in 1993.

See also PSR B1257+12 Delta Trianguli Pulsar planet List of exoplanets discovered before 2000 - PSR B1620-26 b

References

External links SolStation: PSR B1620−26 SPACE: Oldest Known World Conjures Prospect of Ancient Life

Illustrations

Worked examples

Example 1 — a first encounter with PSR B1620−26

Start with the simplest possible case. Write down what PSR B1620−26 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 PSR B1620−26 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 PSR B1620−26 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 PSR B1620−26

In research: PSR B1620−26 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 PSR B1620−26 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: PSR B1620−26 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Binary stars, Multi-star planetary systems, Multiple compact object systems, so understanding it makes those chapters shorter.
In everyday life: Look for PSR B1620−26 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 PSR B1620−26 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what PSR B1620−26 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 PSR B1620−26 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is PSR B1620−26 in simple terms?

Why does PSR B1620−26 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 PSR B1620−26?

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 PSR B1620−26.