astronomy

Gaia BH1

Gaia BH1 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 Gaia BH1 rather than just read about it. In short: Gaia BH1 (Gaia DR3 4373465352415301632) is a binary system consisting of a G-type main-sequence star and a stellar-mass black hole, located about 1,560 light-years (478 pc) away from the Solar System in the constellation of Ophiuchus. As of 2026, it is the nearest known system that astronomers are reasonably confident contains a black hole, followed by Gaia BH3, Gaia BH2 and A0620-00.

Key takeaways

Gaia BH1 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Gaia BH1 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Gaia BH1 from memory before moving on to harder problems.

Reference excerpt

Gaia BH1 (Gaia DR3 4373465352415301632) is a binary system consisting of a G-type main-sequence star and a stellar-mass black hole, located about 1,560 light-years (478 pc) away from the Solar System in the constellation of Ophiuchus. As of 2026, it is the nearest known system that astronomers are reasonably confident contains a black hole, followed by Gaia BH3, Gaia BH2 and A0620-00.

Characteristics

The star and black hole orbit each other with a period of 185.387 days and an eccentricity of 0.4323. The star is similar to the Sun, with about 0.93 M☉ and 0.99 R☉, and a temperature of about 5,850 K (5,580 °C; 10,070 °F), while the black hole has a mass of about 9.62 M☉. Given this mass, the black hole's Schwarzschild radius should be about 28 km (17 mi).

Discovery

Gaia BH1 was discovered in 2022 via astrometric observations with Gaia, and also observed via radial velocity. The discovery team found no astrophysical scenario that could explain the observed motion of the G-type star, other than a black hole. The system differs from "black hole impostors" such as LB-1 and HR 6819 in that the evidence for a black hole does not depend on the mass of the star or the inclination of the orbit, and there is no evidence of mass transfer. The discovery team also found a second system that is a candidate for containing a black hole, which was also reported by another team of astronomers, and was confirmed in 2023 as Gaia BH2. The black hole was also independently detected by a second team, who found slightly different parameters.

See also List of nearest known black holes Gaia BH2 Gaia BH3 GRS 1915+105 OGLE-2011-BLG-0462 VFTS 243

References

Illustrations

Worked examples

Example 1 — a first encounter with Gaia BH1

Start with the simplest possible case. Write down what Gaia BH1 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 Gaia BH1 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 Gaia BH1 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 Gaia BH1

In research: Gaia BH1 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 Gaia BH1 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: Gaia BH1 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astrometric binaries, Astronomical objects discovered in 2022, G-type main-sequence stars, so understanding it makes those chapters shorter.
In everyday life: Look for Gaia BH1 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 Gaia BH1 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Gaia BH1 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 Gaia BH1 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Gaia BH1 in simple terms?

Why does Gaia BH1 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 Gaia BH1?

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 Gaia BH1.