astronomy

Proplyd 114-426

Proplyd 114-426 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 Proplyd 114-426 rather than just read about it. In short: Proplyd 114-426 is a large protoplanetary disk seen in absorption in front of the emission of the Orion Nebula. It is one of the largest protoplanetary disks in the Orion Nebula with a diameter of 950 AU.

Key takeaways

Proplyd 114-426 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Proplyd 114-426 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Proplyd 114-426 from memory before moving on to harder problems.

Reference excerpt

Proplyd 114-426 is a large protoplanetary disk seen in absorption in front of the emission of the Orion Nebula. It is one of the largest protoplanetary disks in the Orion Nebula with a diameter of 950 AU.

Discovery Proplyd 114-426 was discovered in 1996 by Mark McCaughrean and Robert O'Dell with images of the Hubble Space Telescope. The central star was hidden behind the edge-on disk, but the disk showed emission nebulae above and below the center with the filter F547M. These nebulae are present because light from the central star is scattered by the dust of the disk. The disk was published together with other so-called proplyds.

The central star While the central star is not seen directly, the scattered light can be used to study the central star. An infrared spectrum was published in 2004, showing that the central star had a spectral type of M0 and intermediate gravity. A mass of 0.58 M☉ and a temperature of 3750 Kelvin were estimated. The rotation of the disk helped to constrain the mass of the central star to below 1 M☉ and a likely mass of 0.4 M☉.

The disk

The disk is one of the largest in the Orion Nebula. Initially the diameter was measured to be 2.3 arcseconds or 1012 AU. The dust mass of the disk was estimated to be 2.9 × 1028 grams (4.6 M🜨) and the total (gas+dust) mass was estimated to be 4.34 × 1030 g (2.29 MJ). Additional Hubble observations showed that the disk is tilted, warped and experiences external photoevaporation. This photoevaporation is caused by diffuse radiation. According to this study the disk should dissipate in a few tens of thousands of years. This study also found that the disk is surrounded by a large "foot-like" structure seen in H-alpha. This "foot-like" structure could however belong to the Herbig-Haro object HH 530, which is located just north of proplyd 114–426. The disk was imaged with ALMA and the disk mass was estimated to be 3.38 ±0.56 MJ. The disk is quite faint at longer wavelengths despite being a large disk. This is explained by the disk being an evolved disk with large particles of solids and ices. The disk is seen in dust continuum emission and absorption in the carbon monoxide band. The disk size was updated to be around 950 AU from Hubble images. The dust emission from ALMA is however confined to the inner region within about 350 AU. JWST NIRCam observed the central part of the Orion Nebula, including proplyd 114–426. This observation found a dip at 3 μm, which is seen as evidence of water ice. The grain size was estimated to be smaller than 0.25 to 5 μm and the dust+ice mass of the disk was estimated to be 0.46 M🜨 in the silhouette region. The dust mass was previously estimated to be 9.9 M🜨 in the scattered light region from ALMA observations. This indicates that while the silhouette is large, it contains a small fraction of mass, due to a small grain size. Absorption of the Paschen-alpha line might also be present, indicating excited hydrogen in the disk. The hydrogen could be excited by the central star or by an external source of ultraviolet light. The morphology from NIRCam images also support a tilted inner disk.

See also List of resolved circumstellar disks Other edge-on disks

Gomez's Hamburger Dracula's Chivito HK Tauri B

References

Illustrations

Worked examples

Example 1 — a first encounter with Proplyd 114-426

Start with the simplest possible case. Write down what Proplyd 114-426 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 Proplyd 114-426 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 Proplyd 114-426 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 Proplyd 114-426

In research: Proplyd 114-426 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 Proplyd 114-426 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: Proplyd 114-426 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1996, Circumstellar disks, M-type pre-main-sequence stars, so understanding it makes those chapters shorter.
In everyday life: Look for Proplyd 114-426 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 Proplyd 114-426 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Proplyd 114-426 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 Proplyd 114-426 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Proplyd 114-426 in simple terms?

Why does Proplyd 114-426 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 Proplyd 114-426?

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 Proplyd 114-426.