I think that it would be to hot to live on earth and we would have never existed
We would not exist. Our sun is a star.
Not quite sure what the intended question was - - - which star are you asking about? The sun IS a star - the one our planet orbits.
If the star Betelgeuse replaced the Sun, most planets will be inside the star, even Jupiter. It would outshine the Sun like the Sun outshines the Moon.
The blue star is hotter
The sun is catagorized as a "yellow star" This is also known as an intermediate star. Blue stars are the hottest. The Sun is not a blue star. - Em
If the Sun was a class "O" star and thus appears "blue", then I think there would be no life on Earth to ask the question. Our star - the Sun - is a class G2 star and has a temperature range of around 5,500 kelvin whereas an "O" star is > 30,000 kelvin.
Our Sun could never become a nova as a nova requires a companion star, and as we only have the one star (The Sun) it is impossible.
It happens all the time. What happens to the Sun? Nothing at all.
An average blue giant is about 5-10 times the size of the Sun and are much hotter than the Sun is. If our Sun were a blue giant, life, as we know it would never have happened. The Earth would have been vastly too hot to support abiogenesis.
There are billions of blue stars, each a different distance from the sun. Please ask about a specific star by name.
Convert into a dwarf white star which is really hot, then a neutron star, and finally, a black hole.
Blue dwarf diameter(sun=1)=4 times the sun's Blue dwarf mass(sun=1)=10 times sun's