astronomy

Ross 19

Ross 19 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 Ross 19 rather than just read about it. In short: Ross 19 is a red dwarf of spectral type M3.5. In 2021 it was discovered that Ross 19 has a companion, which is a cold brown dwarf.

Key takeaways

Ross 19 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Ross 19 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Ross 19 from memory before moving on to harder problems.

Reference excerpt

Ross 19 is a red dwarf of spectral type M3.5. In 2021 it was discovered that Ross 19 has a companion, which is a cold brown dwarf. Ross 19B is likely the coldest brown dwarf found around a main-sequence star, as of July 2024.

Ross 19A Ross 19A was discovered in 1925 by Frank E. Ross as a proper-motion star with the help of the Yerkes Observatory and archived plates by E. E. Barnard. In 1985 the first spectral information was published by W. P. Bidelman, based on observations by G. P. Kuiper, which reported the star to have a V magnitude of 12.70 and a spectral type of M3.5. In 2020 the star was observed at the Lick Observatory and with IRTF. Ross 19A has a mass of about 0.36 M☉ and has an age between 3.6 and 11 billion years. It has a sub-solar metallicity and has a temperature of about 3500 Kelvin. In TESS and ZTF light curves it does not show any variability and does not show any flares.

Ross 19B Ross 19B (also called CWISE J021948.68+351845.3) was initially found in the Backyard Worlds project by the citizen scientists Samuel Goodman, Léopold Gramaize, Austin Rothermich, and Hunter Brooks. It was then observed by the professional astronomers of the paper led by Adam C. Schneider with the Keck Observatory in 2020, measuring a J-band magnitude of 21.14 ± 0.02. The researchers calculated that Ross 19B has a 100% probability to be bound to Ross 19A. Ross 19B has a very low temperature of about 400–615 kelvins (127–342 °C; 260–647 °F), making it either a late T-dwarf or a Y-dwarf. It has a mass between 15 and 40 MJ, making it a brown dwarf. Its wide separation results in an extremely low gravitational binding energy. It is suggested that Ross 19B has a sub-solar metallicity similar to the red dwarf. Later observation with Gemini North showed a Y-band magnitude of 21.86 ± 0.06. This showed that the spectral type is likely between T9 and Y0. A James Webb Space Telescope program is dedicated to observe Ross 19B in Cycle 3.

See also List of Y-dwarfs Wolf 1130C – another cold metal-poor companion WD 0806-661B – a Y-dwarf companion to a white dwarf

References

Illustrations

Worked examples

Example 1 — a first encounter with Ross 19

Start with the simplest possible case. Write down what Ross 19 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 Ross 19 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 Ross 19 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 Ross 19

In research: Ross 19 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 Ross 19 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: Ross 19 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Brown dwarfs, Gliese and GJ objects, M-type main-sequence stars, so understanding it makes those chapters shorter.
In everyday life: Look for Ross 19 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 Ross 19 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Ross 19 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 Ross 19 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Ross 19 in simple terms?

Ross 19 is a red dwarf of spectral type M3.5. In 2021 it was discovered that Ross 19 has a companion, which is a cold brown dwarf.

Why does Ross 19 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 Ross 19?

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 Ross 19.