How far is the Big Dipper from the earth?

It's early spring, and the Big Dipper rises early at night. When we look at the northern sky, we can see seven bright stars arranged in the shape of spoons, which is the Big Dipper. Through the Big Dipper, it is easy to find the Polaris not far away.

So, what are the names of the Big Dipper? What celestial bodies are they? How far is it from the earth?

Like most stars visible to the naked eye in the night sky, the Big Dipper is also a star. They can emit light and heat through nuclear fusion, and they are both bigger than the sun. But we can't feel the heat of the Big Dipper on earth. The Big Dipper looks much smaller than the sun, because the distance between these stars and the earth is several trillion times that between the sun and the earth.

Let's introduce the Big Dipper respectively:

Guang Yao

Eta Ursa major, also known as Pojun in ancient times, is located 103.9 light years away. This star has a solar mass of 6. 1 and a solar radius of 3.4. Because the greater the mass, the more intense the nuclear fusion reaction, so Ursa major η generates more energy per unit time, which is about 594 times that of the sun. The temperature of Eta Ursae Majoris also very high, with the surface temperature exceeding 1.5 million degrees Celsius.

Kaiyang

Kaiyang, also known as Wu Qu in ancient times, is located 82.9 light years away. This star is 2.2 times the mass of the sun, 2.4 times the radius of the sun, 33 times the luminosity of the sun, and the surface temperature is close to 9000 degrees. If you look closely at Kaiyang, you can also see a dim companion star near it. This star is called "Fu", which was used by the ancients to measure eyesight. In addition, there are four stars invisible to the naked eye, which is actually a six-star system.

Yu Heng

Kaiyang, also known as Lian Zhen in ancient times, is located 82.6 light years away. The mass of this star is 2.9 times that of the sun, the radius is 4. 1 times that of the sun, the luminosity is 102 times that of the sun, and the surface temperature is 8700 degrees. Yuheng brightness ranks first in the Big Dipper. Observations show that there may be a companion star around Yuheng, whose mass is estimated to be 15 times that of Jupiter, or a brown dwarf, and the distance between them is about 8.2 million kilometers.

Tianquan

Tianquan, also known as Wen Qu in ancient times, is located 80.5 light years away. The star's mass is 1.6 times that of the sun, its radius is 1.4 times that of the sun, its luminosity is 14 times that of the sun, and its surface temperature is 9200 degrees. This star is younger. It is estimated that it was formed 300 million years ago. In addition, Tian Quan has two companion stars invisible to the naked eye, so this is a "Three-body".

celestial pole

The celestial pole, also known as Lucun in ancient times, is located 83.2 light years away. The mass of this star is 2.9 times that of the sun, its radius is 3 times that of the sun, its luminosity is 65 times that of the sun, and its surface temperature is 9 100 degrees. Tianqi has a companion star with an orbital period of 20.5 years.

Tian Xuan

Tian Xuan, also known as the Great Gate in ancient times, is located 79.7 light years away. The physical parameters of this star are very close to those of the sky star. Tian Xuan is a sub-giant. Its core has run out of hydrogen fuel and is currently cooling.

Shu Tian

Shu Tian, also known as the greedy wolf in ancient times, is located 123 light years away. The mass of this star is 4.3 times that of the sun, the radius is 30 times that of the sun, the luminosity is 3 16 times that of the sun, and the surface temperature is 4380 degrees. Shu Tian is a red giant that has exhausted its core hydrogen fuel, and it also has a companion star whose mass is 1.6 times that of the sun. The distance between the two stars is about 23 astronomical units, and it takes about 45 years to go around.

The distance between the big scoops is not as close as it looks, and they are at least a few light years apart. For example, the distance from the celestial pole to Kaiyang is about 8.6 light years, which is equivalent to the distance from the sun to Sirius; The distance between Tianqi and Tianxuan is 1 1 light years, which is even closer than their distance from the sun.