astronomy

V1149 Orionis

V1149 Orionis 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 V1149 Orionis rather than just read about it. In short: HD 37824 is a spectroscopic binary star system in the constellation of Orion. It has the variable-star designation V1149 Orionis (abbreviated to V1149 Ori).

Key takeaways

V1149 Orionis belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect V1149 Orionis to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of V1149 Orionis from memory before moving on to harder problems.

Reference excerpt

HD 37824 is a spectroscopic binary star system in the constellation of Orion. It has the variable-star designation V1149 Orionis (abbreviated to V1149 Ori). With an apparent magnitude of 6.59, it is near the limit for naked eye observation from Earth, faintly visible as an orange-hued dot of light under dark skies. It is located approximately 492 light-years (151 parsecs) distant according to Gaia DR3 parallax measurements, and is moving further away at a heliocentric radial velocity of 26.90 km/s.

Stellar properties HD 37824 is a single-lined spectroscopic binary, meaning only the light from the luminous primary can be observed in the system's spectra. The two stars orbit each other in a circular orbit (eccentricity 0.0) with a period of 53.57 days. The star features prominent starspots, which are known to display the flip-flop effect; other stars that show this effect include FK Comae Berenices and HD 181809. The primary star (HD 37824 A) is a chromospherically active K-type giant star in the core helium burning phase. It has a radius of 12.6 R☉ and evolutionary models predict that its mass is 1.5–2.5 M☉. It is radiating 67±23 times the luminosity of the Sun from its photosphere. The unseen secondary, B, is estimated to have a mass of 1.10 M☉ if the orbital inclination is 90°, or 0.95–1.27 M☉ with an inclination of 60°, which makes it likely to be a late-F-type or G-type main-sequence star.

Observational history

In 1973, astronomers William P. Bidelman and Darrell Jack MacConnell reported the detection of Ca II H & K emission lines in the spectra of HD 37824. As such, Douglas S. Hall et al. suspected it to be a RS Canum Venaticorum variable. As expected, in 1983, the star was shown to vary in brightness by 0.11 magnitudes, with photometric and orbital periods of 52.6 and 53.6 days, respectively. It was given its variable star designation in 1985. The starspots on the surface of the primary star, which are thought to cause the variability, were analyzed using photometric data taken between late 1978 and early 1990. The results were published in 1991, identifying six starspots, which each made the star dim by about 0.1 to 0.3 magnitudes and lasted for several years. The same study refined the orbital period to 53.58±0.02 days. Observations in 1992 showed a large excess of Hα emission alongside strong Ca II H & K and Hε emission lines. A follow-up study in 1997 reported a lower but still strong Hα emission, as well as a clear emission line from singly ionized helium revealed by spectral subtraction. Additional observations in 2000 discovered high variability in the profile of the Hα line.

Illustrations

Worked examples

Example 1 — a first encounter with V1149 Orionis

Start with the simplest possible case. Write down what V1149 Orionis 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 V1149 Orionis 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 V1149 Orionis 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 V1149 Orionis

In research: V1149 Orionis 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 V1149 Orionis 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: V1149 Orionis is common in secondary-school and first-year university syllabi. It links to neighbouring topics Durchmusterung objects, F-type main-sequence stars, G-type main-sequence stars, so understanding it makes those chapters shorter.
In everyday life: Look for V1149 Orionis 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 V1149 Orionis in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what V1149 Orionis 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 V1149 Orionis out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is V1149 Orionis in simple terms?

HD 37824 is a spectroscopic binary star system in the constellation of Orion. It has the variable-star designation V1149 Orionis (abbreviated to V1149 Ori).

Why does V1149 Orionis 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 V1149 Orionis?

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 V1149 Orionis.