science

WD 2359−434

WD 2359−434 is a science 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 WD 2359−434 rather than just read about it. In short: WD 2359-434 (Gliese 915, LHS 1005, L 362-81) is a nearby degenerate star (white dwarf) of spectral class DAP5.8, the single known component of the system, located in the constellation Phoenix, the nearest star in this constellation. Distance Currently, the most accurate distance estimate of WD 2359−434 is a trigonometric parallax from Gaia DR3: 120.0143±0.0215 mas, corresponding to a distance of 8.332±0.001 pc, or 2…

Key takeaways

WD 2359−434 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect WD 2359−434 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of WD 2359−434 from memory before moving on to harder problems.

Reference excerpt

WD 2359-434 (Gliese 915, LHS 1005, L 362-81) is a nearby degenerate star (white dwarf) of spectral class DAP5.8, the single known component of the system, located in the constellation Phoenix, the nearest star in this constellation.

Distance Currently, the most accurate distance estimate of WD 2359−434 is a trigonometric parallax from Gaia DR3: 120.0143±0.0215 mas, corresponding to a distance of 8.332±0.001 pc, or 27.176±0.005 ly. WD 2359−434 is the 13th closest white dwarf to the Sun.

Physical parameters WD 2359−434's mass is 0.85 ± 0.01 Solar masses, its surface gravity is 108.39 ± 0.01 (2.45 · 108) cm·s−2, or approximately 250,000 of Earth's, corresponding to a radius 6780 km, or 1.06 of Earth's. WD 2359−434 is relatively hot and young white dwarf, its temperature is 8570 ± 50 K; its cooling age, i. e. age as degenerate star (not including lifetime as main sequence star and as giant star) is 1.82 ± 0.06 Gyr. Gliese 518 should appear bluish-white, due temperature, comparable with that of A-type main sequence stars. As all white dwarfs, WD 2359−434 is composed of very dense degenerate matter, its mean density is 1,300,000 g·cm−3, i.e. mass of one cubic millimetre of WD 2359−434 matter is 1.3 kg. Unusually for a white dwarf star, WD 2359-434 has a weak, non-dipole magnetic field of 50,000 - 100,000 Gauss.

Main sequence progenitor properties As all degenerate stars, WD 2359−434 previously existed initially as main-sequence star and then as giant star, until all the thermonuclear fuel was exhausted, after which WD 2359−434 lost most of its mass. According to the 2010 thesis for the degree of Doctor of Science, using Wood model D initial–final mass relation and WD 2359−434's white dwarf mass value 0.97 ± 0.03 M☉ from Holberg et al. 2008, its main sequence progenitor mass was 7.09 M☉. Using expression for pre-white dwarf lifetime 10 · (MMS/M☉)2.5 (Gyr), was found WD 2359−434 main sequence age 0.07 Gyr. White dwarf mass value 0.85 ± 0.01 M☉ from Subasavage et al. 2009, in Wood model D yields MS (main sequence) mass 6.03 M☉, and MS lifetime 0.11 Gyr, corresponding to B-type main sequence star. According to initial-final mass relation from Weidemann 2000 paper, WD 2359−434's main sequence progenitor should have mass about 4.6 M☉ and lifespan 0.22 Gyr, and, again, should be of B spectral type. There are also other models.

See also List of star systems within 25–30 light-years

Notes

References

Illustrations

Worked examples

Example 1 — a first encounter with WD 2359−434

Start with the simplest possible case. Write down what WD 2359−434 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 WD 2359−434 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 WD 2359−434 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 WD 2359−434

In research: WD 2359−434 appears in science 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 WD 2359−434 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: WD 2359−434 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Gliese and GJ objects, Phoenix (constellation), White dwarfs, so understanding it makes those chapters shorter.
In everyday life: Look for WD 2359−434 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 WD 2359−434 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what WD 2359−434 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.
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Frequently asked questions

What is WD 2359−434 in simple terms?

Why does WD 2359−434 matter?

Because it connects several science 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 WD 2359−434?

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 WD 2359−434.