Stars

how are temperature = colour?

The temperature of a star determines its color, with hotter stars appearing blue and cooler stars appearing red.

what are spectral classes?

an absorption line will appear in a spectrum if an absorbing material is placed between a source and the observer - the material could be the outer layer of a star and in this case the absorption lines determine the spectral classes of stars as: O, B, A, F, G, K, M

what are the spectral classes of stars?

The spectral classes of stars are classifications based on their temperature and characteristic absorption lines, categorized as O, B, A, F, G, K, and M, ranging from the hottest to the coolest.

what are solar units?

Solar units are a system of measurement used in astrophysics, defining quantities such as luminosity, mass, and radius relative to the Sun, providing a standardized way to compare other stars to our Sun.

what is the luminosity of stars and what is the formula?

The luminosity of stars refers to the total amount of energy a star emits per unit of time. The formula used to calculate luminosity is L = 4πR²σT⁴, where L is luminosity, R is the radius of the star, σ is the Stefan-Boltzmann constant, and T is the star's effective temperature.

what is the Herzsprung-Russell diagram?

the HR diagram plots stellar luminosity against surface temperatures

what is the range of stars in terms of temperature?

O & B are blueish, they’re the most luminous and hot (20, 000) such as Rigel and Mintaka, A stars are blueish-white (10, 000 degree) like Vega and Sirius, F stars are white-yellowish not as hot (7000) like Canopus, G stars are yellowish (6000) like our sun and alpha-centauri, K & M stars are cooler (3000-5000k) like Betelgeuse & Barnard

what is the formula for the intensity of light?

luminosity/surface area

what is inverse square law?

The inverse square law states that the intensity of light or radiation from a point source is inversely proportional to the square of the distance from the source. As distance increases, the strength of a force (like gravity or light) decreases with the square of the distance.

what is the formula for apparent brightness?

The formula for apparent brightness is the luminosity of the star divided by the square of the distance from the observer.

what are the spectral classes in order of colours in order of hottest to coolest?

o, b, a, f, g, k, m

what does r, m, t, and l stand for?

r means radii, m means mass, t means temperature, and L means luminosity

a baby star in formation is called what? and the gas and dust cloud is called what?

a protostar and a nebula

what is the minimum mass needed to make a star?

0.08 solar masses

how to calculate parasec

1/distance (pc) and light years to parsec is 3.25x the amount of light years.

what is the minimum mass to make a star and how much more mass does jupiter need to become a star?

A star needs a minimum mass of 0.08 solar masses, and Jupiter would require about 80 times its current mass to ignite nuclear fusion.

what is the size & luminosity for main sequence stars?

the more massive the star the more luminous it is, mass is correlated with radius and luminosity

how to calculate intensity

luminosity/surface area