Characteristic of Stars Constellation – an imaginary pattern of stars in the sky. Astronomers classify stars according to their physical characteristi Color Temperature Size Composition Brightness Color and temperature: Cooler stars (3!""oC# appear reddish $ Betelguese %edium stars (&&""oC# appear yello' – our sun ottest stars (o)er !""""oC# are *lue – +igel (see picture *elo': Blue stars hottest +ed stars coolest#
Characteristic of StarsConstellation an imaginary pattern of
stars in the sky.
Astronomers classify stars according to their physical
characteristics:ColorTemperatureSizeCompositionBrightnessColor and
temperature:Cooler stars (3,200oC) appear reddish -
BetelgueseMedium stars (5,500oC) appear yellow our sunHottest stars
(over 20,000oC) are blue Rigel(see picture below: Blue stars
hottest , Red stars coolest)
Size:Small stars are called white dwarfsLarge stars are called
red giant or supergiant
Brightness:The brightness of a star depends on its size and
temperature.Apparent brightness the brightness of a star as seen
from Earth.Absolute brightness- an astronomer must find out both
the stars apparent brightness and its distance from
Earth.Hertzsprung-Russell Diagram (H-R diagram) a graph that
relates the surface temperatures and absolute brightness of
stars.
Parallax the apparent change in position of an object when seen
from different places.
![Classification of Spectra of Emission Line Stars Using ... · the most common types, they are Be stars, B[e] stars, pre-main-sequence stars (e.g. T Tau and Herbig stars), stars with](https://img.pdfslide.net/doc/110x75/60662ee633f4d23c133aa4a1/classiication-of-spectra-of-emission-line-stars-using-the-most-common-types.jpg)
