Hi!
1. Stars are formed of extremely hot gas. This gas is made of light elements, which are mainly hydrogen and helium. These gases are burned by the star to run their core (nuclear fusion), a process which gives rise to the formation of heavier elements. As stars die out, they release a lot of these heavier elements into space, from which other stars may form; hence, a lot of stars are seen to contain small amounts of heavier elements, which are carbon, iron, oxygen and nitrogen which are remnants of the stars they were created from.
2. The apparent motion of the stars across the sky is attributed to the rotation and orbit of the Earth. This apparent motion is also observed in other celestial bodies in the sky, and the reason is the same. The rotation of the Earth drives us Eastward at a speed of 1000mph, which is makes the stars seem like they gradually rise from the East, pass, and set into the West.
3. Also known as a star chart, is basically a map of the night sky. The map is portioned into grids which makes cosmic bodies such as stars, constellations, nebulae and others easier to locate -making them an essential tool to humans for navigation, and allowing for easier identification and plotting of stars and constellations. Sky maps are made by plotting every celestial body carefully onto an advanced diagram, observing the sky every night for peripheral changes for a year. The celestial sphere is divided into eighty eight different sections, with each segment of the sky holding a particular constellation in them. Nowadays photographs and satellites are employed to make star maps.
4. The appearance of the star depends on its composition. Stars are made predominantly from hydrogen and helium gas, but also of various other elements in varying concentrations such as iron, calcium, oxygen, nitrogen and carbon. Each element has the capacity to absorb a particular wavelength of light, resulting in the emission of different colors. These colors allow for scientists to determine the composition of the stars.
5. The Spitzer telescope is a powerful, infrared space telescope which is equipped with the ability to picture different temperatures. The Spitzer telescope can photograph particular celestial bodies which are too distant, cool or too dim to be captured by conventional telescopes. With regard to stars, Spitzer has served to capture the earliest phases of the birth of stars, adding to our understanding of their formation, which has previously been a process that was concealed behind clouds of dust. Spitzer can also identify stars, such as Brown Dwarfs that are much colder than the sun, and have been otherwise hard to observe.
Hope this helps!