The Sun Star or Planet ?

Astronomers Size Color Brightness

Color Hottest Coolest Red Orange Yellow White Blue

Size - 6 Main Categories Dwarf Main Sequence Sub Giant Giant Bright Giant Super Giant

White Dwarfs Almost the same size as Earth!

Brightness Depends on the size and temperature. Apparent Magnitude – how bright they look from Earth. Absolute Magnitude – how bright they are as if they are the same distance from Earth.

Very hot, blue Stars (top left) Cooler, red Stars (top right)

Which Star is brighter?

Why are some Stars Brighter than others? If a dwarf star and a Super Giant contained the same amount of matter, the dwarf star would have higher density than the Super giant. Density – the amount of matter an object contains. Weight Age Higher Density levels

The Wanderers Planets travel in the night sky. The word “Planet” means wanderer in ancient languages. What does a planet look like in the night Sky? They look like stars. Why don’t planets twinkle? The light from a close planet does not refract the same as the light from a distant star. Planets may also look brighter than stars.

Planets Visible Now Where are the planets located know? Mercury Venus Mercury is in the southwest evening sky, getting slightly better as the month progresses up to its greatest eastern elongation on the 22nd. Shortly after that it will decline and be lost by the end of the month.                 Venus Venus still rules the predawn eastern sky. It is not as bright and perhaps not quite as prominent as it was several months ago, but it remains un-missable. A thick Crescent Moon passes near it on the 4th and 5th. Mars Mars is slightly past its December prime but still bright and easily found in Taurus. It is in the northeastern heavens at sunset, highest late in the evening, and goes down in the northwest at about sunrise. Jupiter Jupiter is in Sagittarius, in the morning sky, but too close to the Sun to be seen easily at the beginning of the month. Observing becomes easier as the month goes on. By the end of the month it is approaching Venus in the southeastern morning twilight. Venus passes about a half degree away on the morning of Feb. 1. Saturn Saturn is in Leo, rising in the late evening at the beginning of the month (4-5 hours after sunset). By the end of the month is rises only 2-3 hours after sunset and thereafter can be seen the rest of the night. Look for the Moon nearby on the evening of the 24th and before dawn on the 25th. Where are the planets located know?

ORION The Hunter The most noticeable star is the bright red-orange star at the figure's left shoulder (upper-left). This is the variable star Betelgeuse - a red giant star. The star at the lower-right (right leg/knee) is Rigel, a blue-white supergiant star. The three stars crossing the centre of the figure are Orion's belt, and vertically below the belt is Orion's sword three stars close together - the central one noticeably fuzzy in this optical image. This is the Orion Nebula (cloud) - a place were many stars are forming right now - a stellar nursery!