Lets learn something about space

Today's topic: Spica AND Type II Supernovae



Seen above as the blue star to the right of the moon, Spica is the brightest star in Virgo and the 15th or 16th brightest star in the sky, as it and Antares are of similar brightness and sometimes listed differently. Spica is 250 light years (6 trillion x 250 miles) away and 23,000 times brighter than our sun. It is actually a binary star, which means that it is two stars that are orbiting one another around a common center, as shown below



Pretty gnarly huh? These two stars are just 0.12 astronomical units apart. An astronomical unit is the distance between our sun and Earth. One astronomical unit is roughly 93 million miles, so these two stars are only 11,160,000 miles apart from each other and orbit one another once every 4 days. This makes their mutual gravity so strong that it actually distorts each star into an egg shape, rather than spherical.

These two stars are very hot, burning at 40,000 and 33,000 degrees Fahrenheit. For comparison, our sun burns at just 10,000 degrees. The primary star has 10 times the mass and 7 times the radius of our sun and is actually the closest star to our sun that is capable of ending its life with a Type II Supernova. Which will, in turn, end the life of the smaller star.

Type II supernovae are distinguished from plain, old, boring supernovae by the presence of hydrogen. Unlike the Sun, massive stars possess the mass needed to fuse elements that have an atomic mass greater than hydrogen and helium, albeit at increasingly higher temperatures and pressures, causing increasingly shorter stellar life spans. The star fuses increasingly higher mass elements, starting with hydrogen and then helium, progressing up through the periodic table until a core of iron and nickel is produced. See below



Fusion of iron or nickel produces no net energy output, so no further fusion can take place, leaving the nickel-iron core inert. Due to the lack of energy output creating outward pressure, equilibrium is broken and the core collapses on itself due to how great its mass is, creating an explosion that looks like this:



tight.

If you want to see this star with the naked eye, youll want to follow the handle of the Big Dipper through Arcturus, as the image below depicts



Fun Fact: Spica is one of the stars seen on the Brazillian national flag.