Concrete is the most common artificial composite material of all and typically consists of loose stones (aggregate) held with a matrix of cement. Concrete is a very robust material, much more robust than cement, and will not compress or shatter even under quite a large compressive force.
2) Y-axis contains absolute brightness Why do astronomers use the H-R Diagram? Astronomers use H-R Diagrams to classify stars and to understand how stars change over time.
With an apparent magnitude of 0.4, Procyon is the 8th brightest star in the entire sky (see: 50 Brightest Stars).Its absolute magnitude is 2.68 and its distance is 11.4 light years. The Equinox J2000 equatorial coordinates are RA = 07h 39m 18.1s, Dec = +05Â° 13' 30.rocyon has a spectral type of F5IV, a surface temperature of 6650Â° Kelvin and a luminosity 6.9 times the Sun.