astronomy

Ross 128

Ross 128 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 128 rather than just read about it. In short: Ross 128 is a red dwarf star in the equatorial zodiac constellation of Virgo, near β Virginis. The apparent magnitude of Ross 128 is 11.13, which is too faint to be seen with the unaided eye.

Key takeaways

Ross 128 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 128 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Ross 128 from memory before moving on to harder problems.

Reference excerpt

Ross 128 is a red dwarf star in the equatorial zodiac constellation of Virgo, near β Virginis. The apparent magnitude of Ross 128 is 11.13, which is too faint to be seen with the unaided eye. Based upon parallax measurements, the distance of this star from Earth is 11.007 light-years (3.375 parsecs), making it the twelfth closest stellar system to the Solar System. It was first cataloged in 1926 by American astronomer Frank Elmore Ross. It is the nearest star in Virgo, and so is occasionally called "Proxima Virginis" by analogy with Proxima Centauri.

Properties

This low-mass star has a stellar classification of M4 V, which places it among the category of stars known as red dwarfs. It has about 18% of the mass of the Sun and 20% of the Sun's radius, but generates energy so slowly that it has only 0.033% of the Sun's visible luminosity; however, most of the energy being radiated by the star is in the infrared band, with the bolometric luminosity being equal to 0.37% of solar. This energy is being radiated from the star's outer atmosphere at an effective temperature of 3,180 K. This gives it the cool orange-red glow of an M-type star. Ross 128 is an old disk star, which means it has a low abundance of elements other than hydrogen and helium, what astronomers term the star's metallicity, and it orbits near the plane of the Milky Way galaxy. The star lacks a strong excess of infrared radiation. An infrared excess is usually an indicator of a dust ring in orbit around the star.

In 1972, a flare was detected from Ross 128. It was observed to increase in brightness by about half a magnitude in the ultraviolet U band, returning to normal brightness in less than an hour. At optical wavelengths, the brightness changes were almost undetectable. It was classified as a flare star and given the variable star designation FI Virginis. Because of the low rate of flare activity, it is thought to be a magnetically evolved star. That is, there is some evidence that the magnetic braking of the star's stellar wind has lowered the frequency of flares, but not the net yield. Brightness variations thought to be due to rotation of the star and magnetic cycles similar to the sunspot cycle have also been detected. These cause changes of just a few thousandths of a magnitude. The rotation period is found to be 165.1 days, and the magnetic cycle length 4.1 years. Ross 128 is orbiting through the galaxy with an eccentricity of 0.122, causing its distance from the Galactic Center to range between 26.8–34.2 kly (8.2–10.5 kpc). This orbit will bring the star closer to the Solar System in the future. The nearest approach will occur in approximately 71,000 years, when it will come within 6.233 ± 0.085 ly (1.911 ± 0.026 pc).

Planetary system

Ross 128 b was discovered in July 2017 by the HARPS instrument at the La Silla Observatory in Chile, by measuring changes in radial velocity of the host star. Its existence was confirmed on 15 November 2017. It is the second-closest known Earth-size exoplanet, after Proxima b. Ross 128 b has a minimum mass 1.4 times that of Earth; a 2019 study predicts a true mass about 1.8 times Earth and a radius about 1.6 times that of the Earth, with large margins of error. It orbits 20 times closer to its star than Earth orbits the Sun, intercepting only about 1.38 times more solar radiation than Earth, increasing the chance of retaining an atmosphere over a geological timescale. Ross 128 b is a closely orbiting planet, with a year (orbital period) lasting about 9.9 days. At that close distance from its host star, the planet is most likely tidally locked, meaning that one side of the planet would have eternal daylight and the other would be in darkness. Near-infrared high-resolution spectra from APOGEE have demonstrated that Ross 128 has near solar metallicity; Ross 128 b therefore most likely contains rock and iron. Furthermore, recent models generated with these data support the conclusion that Ross 128 b is a "temperate exoplanet in the inner edge of the habitable zone."

A 2024 study of the radial velocity data found an eccentricity of about 0.21 for Ross 128 b, higher than previous estimates and similar to that of Mercury. Given the planet's orbit near the inner edge of the habitable zone, such a high eccentricity would significantly decrease its potential for habitability. This study also searched for additional planets in the system, and did not find any.

Radio signals In the spring of 2017, Arecibo astronomers detected strange radio signals thought to originate from Ross 128 that were unlike any they had seen before. SETI's Allen Telescope Array was used for follow-up observations and was unable to detect the signal but did detect man made interference, making it seem clear that the Arecibo detections were due to transmissions from Earth satellites in geosynchronous orbit. Ross 128 has a declination (a coordinate which can be likened to latitude) of close to 0 degrees, which places it in the thick of a phalanx of these satellites. Therefore, it can be concluded that the signal was most likely a result of man-made interference.

See also List of nearest stars and brown dwarfs PSR B1919+21 – pulsar mistaken for an alien radio signal (LGM-1)

References

External links

SolStation.com: Ross 128

Illustrations

Worked examples

Example 1 — a first encounter with Ross 128

Start with the simplest possible case. Write down what Ross 128 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 128 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 128 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 128

In research: Ross 128 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 128 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 128 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1926, Emission-line stars, Flare stars, so understanding it makes those chapters shorter.
In everyday life: Look for Ross 128 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 128 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Ross 128 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 128 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Ross 128 in simple terms?

Ross 128 is a red dwarf star in the equatorial zodiac constellation of Virgo, near β Virginis. The apparent magnitude of Ross 128 is 11.13, which is too faint to be seen with the unaided eye.

Why does Ross 128 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 128?

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 128.