astronomy

Teegarden's Star b

Teegarden's Star b 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 Teegarden's Star b rather than just read about it. In short: Teegarden's Star b (also known as Teegarden b) is an exoplanet found orbiting within the habitable zone of Teegarden's Star, an M-type red dwarf 12.5 light-years away from the Solar System. It had the highest Earth Similarity Index (ESI) of any exoplanet, but in February 2024 a new study updated the parameters of the planet, thus reducing its ESI to 0.90, making it no longer the planet with the hightest ESI.

Key takeaways

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

Reference excerpt

Teegarden's Star b (also known as Teegarden b) is an exoplanet found orbiting within the habitable zone of Teegarden's Star, an M-type red dwarf 12.5 light-years away from the Solar System. It had the highest Earth Similarity Index (ESI) of any exoplanet, but in February 2024 a new study updated the parameters of the planet, thus reducing its ESI to 0.90, making it no longer the planet with the hightest ESI. Along with Teegarden's Star c, it is among the closest-known potentially habitable exoplanets.

Discovery In July (2019), a team of more than 155 scientists led by Mathias Zechmeister published a peer-reviewed article in Astronomy & Astrophysics as part of the CARMENES survey supporting the existence of two candidate exoplanets orbiting Teegarden's Star. Because of the alignment and faintness of Teegarden's Star, Doppler spectroscopy (also known as the radial velocity method) was necessary to detect possible exoplanets. This method detects exoplanets indirectly by observing their effects on a host star's radial velocity, the speed at which it is moving towards or away from the Earth. These radial velocity anomalies in turn produce doppler shifts observable with a spectrograph-equipped telescope of sufficient power. To accomplish this, the team used the CARMENES instrument on the 3.5-metre (11 ft) telescope of Spain's Calar Alto Observatory. After three years of observation, two periodic radial velocity signals emerged: one at 4.91 d (Teegarden's Star b) and another at 11.41 d (Teegarden's Star c).

Physical characteristics

Mass and orbit Teegarden's Star b is the innermost-known planet orbiting Teegarden's Star, with an orbital period of just 4.91 d. The planet's minimum mass is 1.05 M🜨; this value would be the true mass if the planet's orbit is not inclined from the Earth's perspective. Because of this, Teegarden's Star b is likely to be rocky. Astronomers estimate that Teegarden's Star b has a 60 percent chance of having liquid water, but an extremely low chance (3%) of having an atmosphere.

Host star

Teegarden's Star is a low-mass red dwarf, with a mass of around 9 percent the mass of the Sun, and with a temperature of around 2,900 K (2,630 °C; 4,760 °F). Due to the very low temperature and luminosity of Teegarden's Star, it was only discovered in 2003, since it has an apparent magnitude of only 15.1 (and an absolute magnitude of 17.22). Like most red and brown dwarfs, it emits most of its energy in the infrared spectrum. It is also older than the Sun, with an age of at least 8 billion years.

Habitability

Teegarden's Star b orbits within the habitable zone of its host star, meaning it is possible that its atmospheric composition could allow for stable liquid water on its surface, which could have also allowed the development of life. Though due to the star being a red dwarf, Teegarden B orbits extremely close to be in the habitable zone, which means the planet is likely tidally locked due to tidal forces.

See also List of nearest exoplanets List of potentially habitable exoplanets

References

Illustrations

Worked examples

Example 1 — a first encounter with Teegarden's Star b

Start with the simplest possible case. Write down what Teegarden's Star b 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 Teegarden's Star b 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 Teegarden's Star b 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 Teegarden's Star b

In research: Teegarden's Star b 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 Teegarden's Star b 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: Teegarden's Star b is common in secondary-school and first-year university syllabi. It links to neighbouring topics Aries (constellation), Exoplanets detected by radial velocity, Exoplanets discovered in 2019, so understanding it makes those chapters shorter.
In everyday life: Look for Teegarden's Star b 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 Teegarden's Star b in 20 minutes

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

Frequently asked questions

What is Teegarden's Star b in simple terms?

Why does Teegarden's Star b 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 Teegarden's Star b?

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 Teegarden's Star b.