Lesson plan
Lambda Ursae Minoris
Lambda Ursae Minoris (λ UMi, λ Ursae Minoris) is a star in the constellation Ursa Minor. It is an M-type red giant with an apparent magnitude of +6.38, making it very faintly visible to the naked eye under the best observing conditions. It is approximately 880 light years from Earth. for Lambda Ursae Minoris, plotted from Hipparcos data Lambda Ursae Minoris is an asymptotic giant branch (AGB) star, a star that has exhausted its core hydrogen and helium and is now fusing material in shells outside its core. AGB stars are often unstable and tend to pulsate, and Lambda Ursae Minoris is classified as a semiregular variable star and its brightness varies by about 0.1 magnitudes. Its variability was discovered by the Hipparcos satellite and it was entered into the General Catalogue of Variable Stars in 1999. This star was used from 1882 as a reference to measure the magnitudes of stars in the northern hemisphere for the 1908 Revised Harvard Photometry catalogue. Sigma Octantis was used for the southern hemisphere. It was then noted that "Neither of these stars appears to vary perceptibly" but that, due to the procedures used "if they did, the variation would have no effect on the final measures."
Article summary
Lambda Ursae Minoris (λ UMi, λ Ursae Minoris) is a star in the constellation Ursa Minor. It is an M-type red giant with an apparent magnitude of +6.38, making it very faintly visible to the naked eye under the best observing conditions. It is approximately 880 light years from Earth. for Lambda Ursae Minoris, plotted from Hipparcos data Lambda Ursae Minoris is an asymptotic giant branch (AGB) star, a star that has exhausted its core hydrogen and helium and is now fusing material in shells outside its core. AGB stars are often unstable and tend to pulsate, and Lambda Ursae Minoris is classified as a semiregular variable star and its brightness varies by about 0.1 magnitudes. Its variability was discovered by the Hipparcos satellite and it was entered into the General Catalogue of Variable Stars in 1999. This star was used from 1882 as a reference to measure the magnitudes of stars in the northern hemisphere for the 1908 Revised Harvard Photometry catalogue. Sigma Octantis was used for the southern hemisphere. It was then noted that "Neither of these stars appears to vary perceptibly" but that, due to the procedures used "if they did, the variation would have no effect on the final measures."
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Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
- Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
Bibliography
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Key claims and bibliography are generated from the same tracked claims and sources as the article page.