Episode 3 is all about the star Sirius!
Episode 3 Synopsis
The ship arrives at Sirius, 8 lightyears away from Earth the star appears blue rather than orange and is double the size of our Sun. The crew, initially amazed by the bright blue glow begin to scan the star as they orbit around it. Slowly another much smaller white star, about the size of Earth comes into view around the horizon of the large Sirius. After gathering data and energy from the large star the ship moves to look at the second smaller star, which most of the crew underestimate. After scanning has begun SAI informs the crew that the star was previously more than double the size of Sirius and because of this burned out much faster, and despite it's size the surface temperature of the small star is actually almost triple that of the larger star. All of the crew apart from the captain are surprised that such a small star could still output so much energy and heat, the crew excited by this start to shout at SAI orders to move to the nearest white dwarf star to them, SAI looks around to the captain and says "Sir?" as the engines begin to ready, to which he nods and the ship shoots off to it's next destination.
Research:
The Sirius star is the brightest star in the night sky, this is due to it's proximity to Earth, being the 7th closest star to our solar system and far more luminous than any of the others. It is still less bright than Venus and Jupiter appear in our night sky, and occasionally less bright than Mars. Sirius is 25 times brighter than our Sun.
Although Sirius appears as a single bright star it is in fact another binary system, the 2 stars are known as Sirius A and Sirius B.
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| This image is from the Hubble Space Telescope, Sirius A is central, and you can just about make out Sirius B slightly below and left as a small dot. |
Originally Sirius B was considerably larger than A, but being such a large star burnt through it's fuel (hydrogen) quickly, grew to a red supergiant and eventually shed it's outer layers to become a 'white dwarf' star around 120 million years ago. Sirius A being less than half the size of Sirius B during it's main sequence is burning it's fuel slower and is expected to finish it's main sequence (meaning that it will become a red supergiant) in around 1 billion years.
The surface temperature of Sirius A (the larger one) is 9,900K (Kelvin) where as the surface temperature of the smaller star Sirius B is 25,000K, but being a white dwarf Sirius B has passed it's period of life where reaction is occurring in it's core, white dwarves slowly cool down and dim. The white dwarf of a star of 0.5 to 8 solar masses such as this one eventually dim and will become a 'black dwarf' though this process takes such a long time that non are currently thought to exist, almost all white dwarfs are still shining brightly and will for the foreseeable future.
The white dwarf star Sirius B is one of the larger white dwarves recorded, with an estimated solar mass approximately the same as our sun, compressed into a sphere the size of Earth.
It is important to remember that despite their size difference, the mass of Sirius A is only around double that of Sirius B. Sirius B effects the orbit of Sirius A more than it's size makes you think it would, they take 50 years to orbit around a barycenter still inside Sirius A but quite off-center.
I think that's enough fact to squeeze into the episode for now.
Matty out!
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