astronomy

Stéphane Udry

Stéphane Udry 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 Stéphane Udry rather than just read about it. In short: Stéphane Udry (born 1961 in Sion, Switzerland) is an astronomer at the Geneva Observatory in Switzerland, whose current work is primarily the search for extra-solar planets. He and his team, in 2007, discovered a possibly terrestrial planet in the habitable zone of the Gliese 581 planetary system, approximately 20 light years away in the constellation Libra.

Key takeaways

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

Reference excerpt

Stéphane Udry (born 1961 in Sion, Switzerland) is an astronomer at the Geneva Observatory in Switzerland, whose current work is primarily the search for extra-solar planets. He and his team, in 2007, discovered a possibly terrestrial planet in the habitable zone of the Gliese 581 planetary system, approximately 20 light years away in the constellation Libra. He also led the observational team that discovered HD 85512 b, another most promisingly habitable exoplanet.

Career Udry earned a doctorate at the University of Geneva in 1992, and spent two years at Rutgers University in New Jersey. Later, Udry returned to Geneva, and worked with Michel Mayor, the discoverer of 51 Pegasi b, the first extrasolar planet found revolving around a normal star. In 2007, Udry was appointed full professor in the faculty of natural sciences at the University of Geneva.

Research Udry's initial research concerned the dynamics of galaxies. His current work chiefly concerns the search for extra-solar planets by analyzing variations in the radial velocities of stars. Among them was Gliese 581c (announced April 25, 2007) which at the time, was the most likely candidate for habitability of any extrasolar planet discovered so far. The planet was discovered by analyzing data obtained by the High Accuracy Radial Velocity Planet Searcher (HARPS) on the European Southern Observatory's 3.6 meter telescope at La Silla Observatory in Chile. He was interviewed by Mat Kaplan on Planetary Radio. Udry described a new instrument known as the Echelle Spectrography for Rocky Exoplanet and Stable Spectroscopic Observations, dubbed ESPRESSO, might allow astronomers to detect Earth-like planets within five to ten years from 2010. An upgraded HARPS, of which Udry lead the observational team, found evidence that Gliese 581d might be more habitable (rather than c or g), and also detected another promising candidate: HD 85512 b.

See also Euler Telescope Next-Generation Transit Survey

References

Illustrations

Worked examples

Example 1 — a first encounter with Stéphane Udry

Start with the simplest possible case. Write down what Stéphane Udry 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 Stéphane Udry 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 Stéphane Udry 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 Stéphane Udry

In research: Stéphane Udry 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 Stéphane Udry 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: Stéphane Udry is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1961 births, 20th-century Swiss astronomers, 21st-century Swiss astronomers, so understanding it makes those chapters shorter.
In everyday life: Look for Stéphane Udry 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 Stéphane Udry in 20 minutes

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

Frequently asked questions

What is Stéphane Udry in simple terms?

Why does Stéphane Udry 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 Stéphane Udry?

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 Stéphane Udry.