astronomy

HD 106906 b

HD 106906 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 HD 106906 b rather than just read about it. In short: HD 106906 b is a directly imaged planetary-mass companion and exoplanet orbiting the star HD 106906, in the constellation Crux at about 336 ± 13 light-years (103 ± 4 pc) from Earth. It is estimated to be about eleven times the mass of Jupiter and is located about 738 AU away from its host star.

Key takeaways

HD 106906 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 HD 106906 b to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of HD 106906 b from memory before moving on to harder problems.

Reference excerpt

HD 106906 b is a directly imaged planetary-mass companion and exoplanet orbiting the star HD 106906, in the constellation Crux at about 336 ± 13 light-years (103 ± 4 pc) from Earth. It is estimated to be about eleven times the mass of Jupiter and is located about 738 AU away from its host star. HD 106906 b is an oddity; while its mass estimate is nominally consistent with identifying it as an exoplanet, it appears at a much wider separation from its parent star than thought possible for in-situ formation from a protoplanetary disk.

Description

HD 106906 b is the only known companion orbiting HD 106906, a spectroscopic binary star composed of two F5V main-sequence stars with a combined mass of 2.71 M☉. Based on the star's luminosity and temperature, the system is estimated to be about 13±2 million years old. The system is a likely member of the Scorpius–Centaurus association. The star is surrounded by a debris disk oriented 21 degrees away from HD 106906 b; this disk is about 65 AU (10 billion km; 6 billion mi) from the binary on its interior and ranges asymmetrically from approximately 120 to 550 AU (18 to 82 billion km; 11 to 51 billion mi) from the binary at its outer edge. Based on its near-infrared spectral-energy distribution, its age, and relevant evolutionary models, HD 106906 b is estimated to be 11±2 MJup, with a surface temperature of 1,800 K (1,500 °C; 2,800 °F). A spectrum with Magellan does show a spectral type of L2.5 ±1 and intermediate gravity. A high-signal-to-noise spectrum was taken with VLT/SINFONI, which resulted in a spectral type of L1.5 ± 1.0 and a temperature of 1820 ± 240 K. Depending on its formation it has a mass of 11.9+1.7−0.8 MJ (hot start) or 14.0+0.2−0.5 MJ (cold start). The high surface temperature, a relic of its recent formation, gives it a luminosity of about 0.02% of the Sun's. While its mass and temperature are similar to other planetary-mass companions/exoplanets like beta Pictoris b or 1RXS J160929.1−210524 b, its projected separation from the star is much larger, about 738 AU (110 billion km; 69 billion mi), giving it one of the widest orbits of any currently known planetary-mass companions. The discovery team evaluated the possibility that HD 106906 b is not gravitationally bound to HD 106906, but is seen close to it along our line of sight and moving in the same direction by chance. The odds of such a coincidence were found to be less than 0.01%.

Discovery Observation of star HD 106906 began in 2005, utilizing the Magellan Telescopes at the Las Campanas Observatory in the Atacama Desert of Chile, some eight years before the companion was discovered. The initial interest in HD 106906 A was directed largely to the debris disk surrounding the star, a pre-main-sequence member of Lower Centaurus–Crux. On December 4, 2013, University of Arizona graduate student Vanessa Bailey, leader of an international team of astronomers, detailed the discovery of HD 106906 b with a paper first published as a preprint on the arXiv and later as a refereed article in The Astrophysical Journal Letters.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with HD 106906 b

Start with the simplest possible case. Write down what HD 106906 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 HD 106906 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 HD 106906 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 HD 106906 b

In research: HD 106906 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 HD 106906 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: HD 106906 b is common in secondary-school and first-year university syllabi. It links to neighbouring topics Circumbinary planets, Crux, Exoplanets detected by direct imaging, so understanding it makes those chapters shorter.
In everyday life: Look for HD 106906 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 HD 106906 b in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what HD 106906 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 HD 106906 b out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is HD 106906 b in simple terms?

Why does HD 106906 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 HD 106906 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 HD 106906 b.