astronomy

Stingray Nebula

Stingray Nebula 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 Stingray Nebula rather than just read about it. In short: The Stingray Nebula (Hen 3-1357) is the youngest-known planetary nebula, having appeared in the 1980s. The nebula is located in the direction of the southern constellation Ara (the Altar), and is located 18,000 light-years (5,600 parsecs) away.

Key takeaways

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

Reference excerpt

The Stingray Nebula (Hen 3-1357) is the youngest-known planetary nebula, having appeared in the 1980s. The nebula is located in the direction of the southern constellation Ara (the Altar), and is located 18,000 light-years (5,600 parsecs) away. Although it is some 130 times the size of the Solar System, the Stingray Nebula is only about one tenth the size of most other known planetary nebulae. The central star of the nebula is the fast-evolving star SAO 244567. Until the early 1970s, it was observed on Earth as a preplanetary nebula in which the gas had not yet become hot and ionized. The image of the nebula shows how the older outer shells of gas are acting as a collimator for the more recent gas outflow from the central star—an important observation, as this process has not been well understood.

History Prior to the discovery of the nebula, its central star was known as He 3-1357, which Karl Gordon Henize classified as an A- or B-type Hα emission-line star in 1976. It was observed in 1971 to be post-asymptotic giant branch B1 or B2 supergiant. Planetary nebula emission lines were identified in this star in 1989 by the International Ultraviolet Explorer. As the nebula would be newly formed and very small, ground-based observations were not able to resolve it; so Matt Bobrowsky observed it with the Hubble Space Telescope, discovering the nebula, which he named the "Stingray Nebula". In 1993, M. Parthasarathy et al. looked at the history of measurements of the brightness of the central star, and concluded that it was fading in the optical region of the spectrum. It was given its variable star designation, V839 Arae, in 1997.

In 1995 the central planetary nebula nucleus was observed as a DA white dwarf, having seemingly faded by a factor of three between 1987 and 1995. The white dwarf has an estimated mass of 0.6 M☉ and luminosity of 3,000 L☉ and has an observed companion star separated by 0.3 arcsecond. The mass of the nebula is estimated as 0.015 M☉. In 1998 Bobrowsky et al. described how the Hubble Space Telescope observations revealed a 17th-magnitude companion to the Stingray's 15th-magnitude central star. The central star is unusual in that it has brightened and faded over a period of 20 years. Its temperature went up by 40,000 °C. An explanation for this is that it has undergone a helium flash. In January 2021, NASA discovered that the nebula had been fading since the 1990s, when it reached its peak brightness. Previously photoionized, the positive ions of the nebula have been recombining with the electrons. In a NASA statement a team member, Martín A. Guerrero of the Instituto de Astrofísica de Andalucía in Granada, Spain, said: "This is very, very dramatic, and very weird. What we're witnessing is a nebula's evolution in real time. In a span of years, we see variations in the nebula. We have not seen that before with the clarity we get with this view."

References

External links Media related to Stingray Nebula at Wikimedia Commons The Scale of the Universe (Astronomy Picture of the Day 2012 March 12) Stingray Nebula at Constellation Guide

Illustrations

Worked examples

Example 1 — a first encounter with Stingray Nebula

Start with the simplest possible case. Write down what Stingray Nebula 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 Stingray Nebula 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 Stingray Nebula 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 Stingray Nebula

In research: Stingray Nebula 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 Stingray Nebula 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: Stingray Nebula is common in secondary-school and first-year university syllabi. It links to neighbouring topics Ara (constellation), Astronomical objects discovered in 1971, Astronomical objects discovered in 1989, so understanding it makes those chapters shorter.
In everyday life: Look for Stingray Nebula 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 Stingray Nebula in 20 minutes

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

Frequently asked questions

What is Stingray Nebula in simple terms?

Why does Stingray Nebula 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 Stingray Nebula?

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 Stingray Nebula.