70 Ophiuchi

70 Ophiuchi (p Ophiuchi) is a binary star system located 16.7 light-years away from the Earth. It shines in the constellation Ophiuchus. Though it looks like a single point of light through the naked eye, telescopes reveal that it is actually made up of two stars orbiting each other.

At magnitude 4, 70 Ophiuchi appears as a dim star to observers far from bright city lights. This means it is just barely visible without any special equipment on a clear, dark night. Many people might never notice it unless they look closely at the right part of the sky.

Binary stars like 70 Ophiuchi are important for astronomers. By studying how these two stars move around each other, scientists can learn about the mass of stars and how they form. This system gives us a close-up example of the fascinating dance that many stars perform in space.

History

This star system was listed in an old star guide from a long time ago, written by Ptolemy in his Almagest. It was called the 28th star in the constellation Ophiuchus.

Later, a scientist named William Herschel discovered that it was made of two stars orbiting each other. He showed that these two stars were tied together by gravity, helping prove that Newton's law of universal gravitation works even for stars far from our Solar System.

Variability

70 Ophiuchi is a variable star, meaning its brightness changes slightly. The combined brightness of the two stars ranges from magnitude 4.00 to 4.03. Scientists aren't sure which star causes these changes or exactly why they happen. They think it might be similar to certain types of variable stars, but they haven't found all the answers yet. They have measured a period of 1.92396 days for these changes.

Binary star

The 70 Ophiuchi system is made up of two stars that orbit each other. One star is a yellow-orange type, and the other is an orange type. They are quite far apart at times and much closer at others, completing one full orbit around each other every 88 years.

Claims of a planetary system

In 1855, an astronomer named William Stephen Jacob thought there might be a planet around the star system 70 Ophiuchi because its orbit seemed unusual. Later, other astronomers made similar claims, but these ideas were proven wrong.

More recent studies have shown that no planets have been found around 70 Ophiuchi, but scientists have not completely ruled out the possibility that small planets might exist there.