Stars and Comets

Twinkle, twinkle. A star is winking at you. There is also a shooting star coming your way (a comet). You make a wish. I love astronomy, the study of stars and the universe.

How a star is born

There is a cloud of gas and dust, and a couple nebulas in space. Over time, (about million or billions of years depending on how big the cloud of gas is) gravity condenses the cloud of gas and dust to make a star. The new-born star is called a protostar. The core is about 10 million K(kelvin) degrees celsius. One Kelvin is 273.16 Celsius. That’s really hot! Eventually, the protostar cools down. It coverts hydrogen into helium and starts shining on its own.

How a star dies

The average life of a star is around 9-10 billion years. The smaller the star, the longer the life. The more massive the star is, it has a shorter life. Our closest star, the sun, is a middle-aged star. It lived for about 4.5 billion years. It also has an average weight and size. There are 3 ways for a star to die:

1- First, the star swells up and gets red. This will happen to the sun, swallowing the inner planets, Mercury, Venus, Earth, and Mars. This is known as a red giant. Then, the star gets really small, even smaller than it was before it became a red giant. This stage is the white dwarf stage. Now it only shines dimly. Eventually, it darkens and becomes a black dwarf.

2- The star can become a neutron star. The neutron forms from a supernova. A supernova is when a big star explodes. A supernova can be as big as an entire galaxy! Then, pieces from the star come to form a neutron star. A neutron star is black and as gigantic as a city.

3- I’m pretty sure I left out the black holes. Black Holes form from supernovas, just like neutron stars. The star has to be very massive to form a black hole. The center of the star collapses in upon itself. Black holes are a mystery. They are also invisible. Nothing can escape it, not even light! So be careful.
Halley’s Comet and Where Comets Come From

Halley’s comet is probably the most popular comet. It was named after Edmond Halley, who obviously proved it was the same comet orbiting the sun. He examined reports of the comet in 1531, 1607, and 1682. He predicted it would come again in 1758. By the time it came again, which it did, he died. He got famous and the comet was named after him.

The last time Halley’s comet came was in 1986. The next time it will come is in about 2061-2062. It has a 75 year orbit around the sun. This only makes it possible for it to be seen by someonce or twice in their lifetime. For me, unfortunately will be once.
Comets come from either the Kuiper Belt or the Oort Cloud. Short-term comets which come from the Kuiper Belt, orbit the sun for less than 200 years. Long-term comets come from the Oort Clouds, which orbit the sun for more than 200 years. Halley’s Comet comes from the Kuiper Belt.

Types of Stars

Binary star- two stars that either orbit one object, or one star orbits the other

Double- Two stars that look really close together from a telescope. Can form to a binary star

Yellow Dwarf- A small, main sequence star. Our sun is a type of yellow dwarf

Red Dwarf- (do not confuse with red giant) Is a cool, small, very faint star. Cool fact: red stars are cool stars and blue stars are hot stars. Proxima Centuri is a red dwarf

Stars close to Earth

1- The sun

2- Proxima Centuri. It is part of a star cluster, Alpha Centuri. Made up of 3 stars

3- Alpha Centuri. Binary star that is part of the cluster Alpha Centuri

4- Barnard’s Star. Part of the constellation Ophiuchus
Stars and comets are a mystery to me. What would we be interested without them?


My drawing of the universe.

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