which planet is the north star?

Question

is it jupiter or venus

Answer 1

Polaris may now be the nearest star to the north pole position but that changes over time.

The previous incumbent was Thuban (α Dra / α Draconis / Alpha Draconis), a star (or star system) in the constellation of Draco. A relatively inconspicuous star in the night sky of the Northern Hemisphere, it is historically significant as having been the north pole star in ancient times.

Even though Thuban carries the Bayer designation Alpha Draconis, at apparent magnitude 3.65 it is over a magnitude fainter than the brightest star in the constellation, γ Dra (Etamin), whose apparent magnitude is 2.23. Thuban is not bright enough to be viewed from light-polluted areas. The Alpha designation is apparently due to its history as the ancient pole star.

Given good viewing conditions, Thuban is relatively easy to spot in the night sky, due to its location in relation to the Big Dipper asterism of Ursa Major. While it is well known that the two outer stars of the 'dipper' point to the modern-day pole star Polaris, it is less well known that the two inner stars, Phecda and Megrez, point to Thuban, just seven and a half degrees of arc from Megrez.

Use as pole star
Due to the precession of Earth's rotational axis, Thuban was the naked-eye star closest to the north pole from 3942 BC, when it moved farther north than Theta Boötis, until 1793 BC, when it was superseded by Kappa Draconis.

It was closest to the pole in 2787 BC, when it was less than two and a half arc-minutes away from the pole. It remained within one degree of true north for nearly 200 years afterwards, and even 900 years after its closest approach, was just five degrees off the pole. Thuban was considered the pole star until about 1900 BC, when the much brighter Kochab began to approach the pole as well.

Having gradually drifted away from the pole over the last 4,800 years, Thuban is now seen in the night sky at a declination of 64° 20' 45.6", RA 14h 04m 33.58s. After moving nearly 47 degrees off the pole by 10000 AD, Thuban will gradually move back toward the north celestial pole. In 20346 AD, it will again be the pole star, that year reaching a maximum declination of 88° 43' 17.3", RA 19h 08m 54.17s.

POLARIS' REIGN AS POLE STAR

Polaris's fame as the North Star has given rise to a persistent misconception that it is the brightest star in the sky. Although Polaris is a relatively bright star and is conspicuous since no other stars of similar brightness are close to it, it is nowhere near the brightest; it is actually the 48th brightest star in the night sky.

The brightest star in the sky (besides the Sun) is Sirius A (8.6 light years away from earth), Polaris is magnitude 2 and 431 light years away from earth. It was as dim as magnitude 3 in Ptolemy's time (200 AD).

Recent research reported in Science suggests that Polaris is 2.5 times brighter today than when Ptolemy observed it (now 2 mag, antiquity 3 mag).

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."

A TRINARY SYSTEM

Polaris is not one star but three: 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; about the distance from our Sun to Uranus) from Polaris A, explaining why its light is swamped by its close and much brighter companion.

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 bright giant (II) or supergiant (Ib). 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. 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.

AFTER POLARIS' REIGN AS POLE STAR IS OVER

Gamma Cephei (also known as Alrai, situated at 45 light-years away) will become closer to the northern celestial pole than Polaris around 3000 AD, and be at its closest approach around 4000 AD.

The "title" then will pass to Iota Cephei (ι Cephei, situated 115 light-years away) some time around 5200 AD.

The first magnitude star Vega will then become the North Star by AD 14,000, due to Precession of the equinoxes.

Vega is the fifth brightest in the sky and a mere 25 light years away from us.

The precession process is slow, but cumulative. A complete precession cycle covers a period of approximately 25,765 years, Thus Vega was last the Pole Star when it fulfilled that role around 12000 BC.

Answer 2

Is The North Star A Planet

Answer 3

The north star is not a planet. The North Star, also called the Pole Star or Polaris, is the star that the earth's axis points toward in the Northern sky. For many years, people have been fascinated with this star and the fact that it doesn't seem to move in the sky. Some have created legends explaining why the star stands still. As more detailed scientific instrumentation has become available, scientists have begun to study more about Polaris. Surprisingly, it is a rich subject consisting of a binary star system.

Answer 4

The North Star is a star not a planet. It is called the North Star because it is above the North Pole. The stars name is Polaris.

Answer 5

The north star is a star, not a planet. Like our sun

Answer 6

It's not a planet. It's a star - completely different thing.

Anyway. The North Star is the star that is nearest to the North Pole. According to wikipedia.org (good old Wikipedia) it is currently Polaris.

Answer 7

The north star is not a planet. It is a star called Polaris resting on the handle of the Little Dipper in Ursa Minor.

Answer 8

The north star is not a planet, it is a star

Answer 9

As its name suggests, the north star is not a planet at all. It's a star!

Answer 10

The north star is not a planet.

Presently it is Polaris, but this is not always the case, Thuban has been it in the past, Alrai will become it in about 2000 years

Answer 11

planet north star