astronomy

Gliese 887

Gliese 887 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 Gliese 887 rather than just read about it. In short: Gliese 887 (GJ 887), also Lacaille 9352 (Lac 9352), is a red dwarf star in the southern constellation of Piscis Austrinus. With an apparent visual magnitude of 7.34, this star is too faint to be viewed with the naked eye except possibly under excellent seeing conditions.

Key takeaways

Gliese 887 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Gliese 887 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Gliese 887 from memory before moving on to harder problems.

Reference excerpt

Gliese 887 (GJ 887), also Lacaille 9352 (Lac 9352), is a red dwarf star in the southern constellation of Piscis Austrinus. With an apparent visual magnitude of 7.34, this star is too faint to be viewed with the naked eye except possibly under excellent seeing conditions. Parallax measurements place it at a distance of about 10.72 light-years (3.29 parsecs) from Earth. It is the twelfth closest star system to the Solar System and is the closest star in the constellation Piscis Austrinus. Its closest neighbour is the EZ Aquarii triple star system at about 4.1 ly away.

Properties

This star has the fourth highest known proper motion, (which was first noticed by Benjamin Gould in 1881) moving a total of 6.9 arcseconds per year. However, this is still a very small movement overall, as there are 3,600 arcseconds in a degree of arc. The space velocity components of this star are (U, V, W) = (−93.9, −14.1, −51.4) km/s. If the radial velocity (Vr) equals +9.7 km/s then about 2,700 years ago Gliese 887 was at its minimal distance of approximately 10.63 ly (3.26 pc) from the Sun. The spectrum of Gliese 887 places it at a stellar classification of M0.5V, indicating it is a type of main sequence star known as a red dwarf. This was the first red dwarf star to have its angular diameter measured, with the physical diameter being about 47% of the Sun's radius. It has around half the mass of the Sun and the outer envelope has an effective temperature of about 3,670 K.

Planetary system In June 2020, two super-Earth planets were reported, as well as a third candidate planet with a period of 50.7 days, located within the habitable zone. They were detected using the radial velocity method from observations with HARPS in Chile and HIRES in Hawaii. A 2026 follow-up study confirmed the 50-day planet and detected a fourth, Earth-mass planet closer to the star. A fifth candidate signal is also suspected. The habitable-zone planet, GJ 887 d, is the second-nearest known exoplanet in the habitable zone after Proxima Centauri b, though it is significantly more massive than Earth and its composition is unknown. It may be possible to characterize it with proposed direct imaging missions such as the Habitable Worlds Observatory. Additionally, the star presents a difference in proper motion measurements taken by the Hipparcos and Gaia spacecraft, suggesting the possible presence of an outer giant planet.

See also List of nearest stars Lalande 21185

References

Worked examples

Example 1 — a first encounter with Gliese 887

Start with the simplest possible case. Write down what Gliese 887 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 Gliese 887 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 Gliese 887 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 Gliese 887

In research: Gliese 887 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 Gliese 887 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: Gliese 887 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Durchmusterung objects, Gliese and GJ objects, Henry Draper Catalogue objects, so understanding it makes those chapters shorter.
In everyday life: Look for Gliese 887 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 Gliese 887 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Gliese 887 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 Gliese 887 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Gliese 887 in simple terms?

Why does Gliese 887 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 Gliese 887?

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 Gliese 887.