Blue and White Supergiants

Blue and White Supergiants are stars with spectral classifications from W (Wolf-Rayet Stars) to A, giving them temperatures between $$200,000$$ to $$7,000$$ degrees Kelvin. They are extremely rare in the universe, with them being less than $$0,001%$$ of stars in the universe. This article will cover a few famous examples of blue supergiant stars.

For blue supergiant stars that are luminous blue variables, see Luminous Blue Variables.

Deneb
Deneb, also known as Alpha Cygni, is the brightest star in the constellation of Cygnus. It is the 19th brightest star in the night sky, with an apparent magnitude of $$1.25$$. A blue-white supergiant, Deneb is also one of the most luminous stars. However, its exact distance and luminosity have been hard to calculate; it is estimated to be somewhere between $$54,000$$ and $$196,000$$ times as luminous as the Sun.

Properties
Deneb's absolute magnitude is currently estimated as $$−8.4$$, placing it among the most luminous stars known, with an estimated luminosity nearly $$200,000$$ times that of the Sun. This is towards the upper end of various published values over the last few decades. Based on its temperature and luminosity, and also on direct measurements of its tiny angular diameter (a mere $$0.002$$ second of arc), Deneb appears to have a diameter of about between $$100$$ to $$200$$ times that of the Sun; if placed at the center of the Solar System, Deneb would extend out to the orbit of the Earth. It is one of the largest known white stars.

Rigel
Rigel is a hot supergiant star in the Milky Way Galaxy. It is classified as a blue supergiant. It is located in the constellation Orion. Many scientists believe that Rigel was the youngest star in the constellation. Rigel lies $$778$$ light-years from Earth in Orion. It is visible from Earth as a small, bluish circle on clear nights from both hemispheres.

It is between $$120,000$$ and $$279,000$$ times brighter than the Sun. Rigel is much bigger than our star here in the solar system, the Sun at between $$78$$ and $$115$$ times its radius. Rigel is actually in a triple star system, with two stars orbiting it at a distance of 14 billion kilometers!

Canopus
Canopus, also known as Alpha Carinae, is a white giant star located 310 light years away in the constellation Carina. It is the second brightest star in the night sky with an apparent magnitude of -0.74. It is only visible in latitudes below $$37°31$$.

It was named after a servant of a king of Sparta.

Iota Carinae
Iota Carinae is a white supergiant with spectral classification A$$9$$. It is a suspected variable star located $$690$$ light years away from the Sun in the It has a luminosity of, a mass of , a temperature of $$7,500$$ degrees Kelvin and a diameter of

In Chinese, 海石 (Hǎi Shí), meaning Sea Rock, refers to an asterism consisting of Iota Carinae, Avior, HD 83183, l Carinae and Upsilon Carinae. Consequently, Iota Carinae itself is known as 海石二 (Hǎi Shí èr, the second of the Sea Rock).

Stars of Orion's Belt
The belt of Orion is the most prominent feature of the Orion constellation. It consists of the blue supergiant stars Alnitak, Alnilam, and Mintaka.

Gamma Velorum
Gamma Velorum is a star system consisting of blue stars located in the Vela constellation.

Properties
This blue star is also sometimes known as Regor - «Roger» spelled backwards, in honor of the astronaut Roger Chaffee, who died in a fire during a routine test onboard the Apollo 1 spacecraft in 1967. Gamma Velorum is a complex star system dominated by a blue subgiant that is poised to evolve off the main sequence. Its evolution has been affected by being in a very close binary orbit with a star that is a Wolf-Rayet star. They lie as close as Earth is to the Sun and orbit each other every 78.5 days. The Wolf-Rayet star is the less massive component of the binary, but started more massive than the blue subgiant but lost mass and evolved quickly. The subgiant is 30 times the Sun's mass and has a surface temperature of 35,270 degrees Kelvin, and a luminosity 20,000 times greater than the Sun. The subgiant is 17 times the diameter of the Sun.

Icarus
Icarus is the name given to the most distant star ever observed from the Earth. It is located 9 billion light years away, so when it was discovered by NASA on April 2018, it was observed as it was 9 billion years ago. It is believed to be a blue supergiant.