Star profile

70 Ophiuchi

Variable star

3D likeness based on its real data · class K · ~4,200 K

What is 70 Ophiuchi

70 Ophiuchi is a binary system just 16.6 light-years away, where two orange dwarfs circle each other every 88 years. In 1779, William Herschel proved its two components were gravitationally bound —one of the first demonstrations that Newton's law applied beyond the Solar System—. In 1855, William Jacob even conjectured the presence of a planet within its orbit. It remains one of the most studied nearby binaries in the northern sky.

Where it is and when to see it

70 Ophiuchi lies in the northern celestial hemisphere. It is visible to the naked eye under a dark sky. Its best month of the year is June, when it culminates around midnight.

From London it culminates about 41° above the horizon.
From New York it culminates about 52° above the horizon.
From Sydney it culminates about 54° above the horizon.

It can be seen from anywhere north of 87° S.

It ranks no. 15 in brightness among the 88 stars of Ophiuchus in our catalogue. To find it, start from Rasalhague, the brightest: it lies about 13° away (a fist at arm's length covers about 10°).

The light you see today left it about 17 years ago.

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Astronomical data for 70 Ophiuchi

Constellation: Ophiuchus
Apparent magnitude: 4.03
Distance: 16.6 light years
Coordinates (J2000): RA 271.364° · Dec 2.500°
Catalogue: HIP 88601 · HD 165341

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Other stars in Ophiuchus

Ophiuchus has 88 stars in Stelvia's catalogue. Here are a few of them.

See all 88 stars in Ophiuchus