what is polaris?

Answer 1

Polaris is the name of the brightest star within the constellation Ursa Minor. Due to its relative position over the earth, in the Northern Hemisphere it is approximately similar to true North and can (and is) used as an aid to navigation

Answer 2

Polaris (α UMi / α Ursae Minoris / Alpha Ursae Minoris) is the brightest star in the constellation Ursa Minor. It is very close to the north celestial pole (42′ away as of 2006), making it the current northern pole star.




Name
"Polaris" comes from Stella Polaris, the Latin form of its common name "Pole Star". The rarely used Greek name Cynosura (Κυνόσουρα) means "tail of the dog" and is the source of the English word cynosure. Other names include the "North Star", the "Lode Star", or sometimes "Polaris Borealis".


Physical properties
Polaris is a trinary system, consisting of a large yellow Cepheid variable (α UMi A), orbited by a bright yellow dwarf (α UMi B) at a distance of about 2400 AU (360 billion kilometers, or 224 billion miles). Polaris B can be seen with even a modest telescope and was first noticed by William Herschel in 1780. In 1929, it was discovered by examining the spectrum of Polaris A that it had another very close dwarf companion (variously α UMi P, α UMi a or α UMi Ab). In January 2006, NASA released images from the Hubble telescope, directly showing all three members of the Polaris trinary system. The nearer dwarf star is in an orbit of only 18.5 AU (2.8 billion km [1]; about the distance from our Sun to Uranus) from Polaris A, explaining why its light is swamped by its close and much brighter companion.[2]

Polaris is 431 light years (132 pc) from Earth, according to astrometric measurements of the Hipparcos satellite. Concerning the detailed physics, α UMi A is an F7 supergiant (Ib) or bright giant (II). The two smaller companions are: α UMi B an F3V main sequence star, orbiting in 2400 AU distance, and C a very close dwarf on a 18.5 AU orbit. Recent observations show that Polaris may be part of a loose open cluster of type A and F stars.

The giant star of Polaris is a classical Population I Cepheid variable (although it was once thought to be Population II due to its high galactic latitude). Since Cepheids are an important standard candle for determining distance, Polaris (as the closest such star) is heavily studied. Around 1900, the star luminosity varied ±8% from its average (0.15 magnitudes in total) with a 3.97 day period; however, the amplitude of its variation has been quickly declining since the middle of the 20th century. The variation reached a minimum of 1% in the mid 1990s and has remained at a low level. Over the same period, the star has brightened by 15% (on average), and the period has lengthened by about 8 seconds each year.

Recent research reported in Science suggests that Polaris is 2.5 times brighter today than when Ptolemy observed it (now 2mag, antiquity 3mag). The astronomer Edward Guinan considers this to be a remarkable rate of change and is on record as saying that "If they are real, these changes are 100 times larger than [those] predicted by current theories of stellar evolution."
— Polaris stands almost motionless on the sky, and all the stars of the Northern sky appear

Answer 3

Polaris is the name for the Pole Star, or North Star. It is a star in the constellation of Ursa Minor, and one of the brightest in the sky. It is called the North Star because it lies very near the north pole, and is visible throughout the year in the Northern Hemisphere.
Its distance is approximately 431 light years.

Answer 4

Polaris

The star α Ursae Minoris, also known as the North Star or Pole Star. It is perhaps the best-known star in the northern sky. Its location only 1 degree of arc from the north celestial pole, the point where the Earth's rotation axis intersects the celestial sphere, has made it a very useful reference point for navigation. It may easily be found by following the line joining the two bright stars at the end of the bowl of the Big Dipper.

Answer 5

Polaris (α UMi / α Ursae Minoris / Alpha Ursae Minoris) is the brightest star in the constellation Ursa Minor. It is very close to the north celestial pole (42′ away as of 2006), making it the current northern pole star.

Answer 6

"Polaris" comes from Stella Polaris, the Latin form of its common name "Pole Star". The rarely used Greek name Cynosura (Κυνόσουρα) means "tail of the dog" and is the source of the English word cynosure. Other names include the "North Star", the "Lode Star", or sometimes "Polaris Borealis".

It's also a song by the band Zero7 :)

Answer 7

It is the name of the star that currently marks the earth's celestial north pole (from the Latin POLARIS meaning POLAR); also called the North Star. It is in the constellation Ursa Minor, a.k.a. the Little Bear, a.k.a. the Little Dipper. It is the star at the tip of the handle .

Answer 8

polaris is the brightest star in the constellation Ursa Minor, and it is currently the north star... because it is situated nearest to the north pole

Answer 9

It's the north star. It's the star positioned almost exactly above the north pole.

Answer 10

its a north star i can't remember if it is the old one or new but it is a north star