ASTRON 2B03 Lecture Notes - Lecture 27: Hipparcos, White Dwarf, Command Paper

• School: McMaster University
• Department: Astronomy
• Course: ASTRON 2B03
• Professor: Laura Parker

Document Summary

If you know the mass of a star, you can know almost anything about the star. However, mass and distance are very hard to determine. Because these are difficult to determine, we use indirect measurements, and correlate those with mass. We can plot brightness and temperature together (hertzsprung-russell. 90-95% of the stars in the sky land in the main sequence , a line in the. The main sequences is where hydrogen burning occurs. Outside of the main sequence, there are supergiants and white dwarves. Hipparcos measured distances to nearby stars, launched in 1989. It makes parallax easier to measure without the blur of the atmosphere. It could measure accurate distances up to 200 parsecs. Hipparcos was one of the first satellites to measure individual cepheid variable distances. Gaia (2013) can measure distances up to 25,000 parsecs. The data has not yet been processed, so it will be some time before we get that publicly.