This probably refers to red dwarves. The apparent magnitude depends on the distance, as well as the absolute magnitude, but even the closest red dwarves can't be seen with the naked eye.
For a long times, it was considered to be VY Canis Majoris, but new studies have reduced its size. The present record is held by UY Scuti at 1708 times the diameter of the Sun. That works out to about 2,250,000,000km.
Magnitudes of stars start in the negative, so the brightest star from Earth is of course the Sun, so it has an apparent magnitude of -26.74 (Note negative), whereas Polaris (The North Star) has an apparent magnitude of +1.97 See related question for differences between apparent and absolute magnitude.
A red dwarf.
Low-temperature stars, such as red dwarfs, are more common in the universe than high-temperature stars. They constitute the majority of stars in our galaxy, primarily due to their long lifespans and the fact that they form more frequently. High-temperature stars, like O and B types, are relatively rare and have shorter lifespans, which contributes to their lower abundance. Overall, the prevalence of low-temperature stars significantly outweighs that of high-temperature stars.
Apparent magnitude is the brightness of an object as seen from Earth without any atmosphere.Absolute magnitude is the brightness of an object as seen from a predetermined distance, depending on the object.For planets, the distance used is 1 AU (Astronomical Units). Stars and galaxies use 10 parsecs which is about 32.616 light years.The dimmer an object is the higher the positive value. The brighter an object is the higher the negative value.Examples:The Sun has an apparent magnitude of -26.74 but an absolute magnitude of 4.83Sirius has an apparent magnitude of -1.46 but an absolute magnitude of -1.42This means that from Earth, the Sun is a lot brighter, but if the Sun was replaced by Sirius, Sirius would be 25 times more luminous.See related links for more information
Absolute magnitude: they are extremely bright. Temperature: their surface temperature is fairly low.
Red giants.
This star would be a white dwarf, as it has a high surface temperature of 20000 K but a low absolute magnitude of 10. White dwarfs are small, dense remnants of low to medium mass stars that have exhausted their nuclear fuel and collapsed.
There are two terms used to describe a stars brightness, absolute magnitude and apparent magnitude. The one you want is absolute magnitude - this is where the stars distance from us is taken out of the equation, effectively comparing the stars brightness side by side from a set distance (10 parsecs or 32.6 light years). Apparent magnitude is the other measure, this is how bright a star apparently looks from Earth. The huge distances and range of distances involved means that you can have very bright stars (high absolute magnitude) that apparently look as bright as a much closer but dimmer (low absolute magnitude) star - their apparent magnitudes might be similar, but they may have vastly different absolute magnitudes.
For a long times, it was considered to be VY Canis Majoris, but new studies have reduced its size. The present record is held by UY Scuti at 1708 times the diameter of the Sun. That works out to about 2,250,000,000km.
Information on millions of stars shows that there is a relationship between temperature and brightness. Surface temperature is measured in degrees C and brightness is measured in absolute magnitude (the star's brightness at a standard distance). If all the stars are plotted on a graph of temperature against absolute magnitude, called a Hertzsprung-Russell diagram, very many of them lie close to a straight line that is called the Main Sequence. There are some stars that do not lie on the Main Sequence, notably the red giants that are very bright despite having a relatively low temperature. The Sun is right in the middle of the Main Sequence showing it is an average star in the middle of its life and very stable.
A star's "absolute magnitude" is a measure of its absolute (or real) brightness. It is defined as the "apparent magnitude" the star would have at a standard distance of 10 parsecs, which is equal to 32.6 light years.
Does it mean that the star is a main sequesnce star? ( . Y . ) The above isn't true. A star can be a blue supergiant and be on the main sequence but still not be even visible to us, therefore the apparent and absolute magnitude wouldn't be the same. But to answer your question, I don't think it has a name, it just means that you are seeing the star's absolute and apparent magnitude at the same time, so if you placed the star at 32.6 light years away(the absolute magnitude scale)then the star would not appear to change in brightness
Information on millions of stars shows that there is a relationship between temperature and brightness. Surface temperature is measured in degrees C and brightness is measured in absolute magnitude (the star's brightness at a standard distance). If all the stars are plotted on a graph of temperature against absolute magnitude, called a Hertzsprung-Russell diagram, very many of them lie close to a straight line that is called the Main Sequence. There are some stars that do not lie on the Main Sequence, notably the red giants that are very bright despite having a relatively low temperature. The Sun is right in the middle of the Main Sequence showing it is an average star in the middle of its life and very stable.
Information on millions of stars shows that there is a relationship between temperature and brightness. Surface temperature is measured in degrees C and brightness is measured in absolute magnitude (the star's brightness at a standard distance). If all the stars are plotted on a graph of temperature against absolute magnitude, called a Hertzsprung-Russell diagram, very many of them lie close to a straight line that is called the Main Sequence. There are some stars that do not lie on the Main Sequence, notably the red giants that are very bright despite having a relatively low temperature. The Sun is right in the middle of the Main Sequence showing it is an average star in the middle of its life and very stable.
The brightest stars have a low magnitude. Magnitude is measured on a logarithmic scale where lower numbers indicate brighter objects. The brightest star in the night sky, Sirius, has a magnitude of -1.46.
Stars in their Main Sequence stage have generally proportional temperature and color. The color-temperature spectrum of a star ranges from red (2000-3000 Kelvins) to blue (25,000+ Kelvins). Red Giants have a relatively high luminosity and low temperatures. White dwarfs have relatively low luminosity and high temperatures. Main Sequence stars are proportional temperature/color therefore they can vary from relatively high luminosity and temperature to relatively low luminosity and temperature.Absolute Magnitude is the star's genuine brightness. It's apparent magnitude is it's brightness from earth. A star can only be accurately classified once data on it's absolute magnitude is acquired.