Star profile

1 Geminorum

3D likeness based on its real data · class G · ~5,500 K

What is 1 Geminorum

1 Geminorum opens Flamsteed's catalogue of the Twins: the first numbered star as the eye sweeps the constellation from west to east. It is a yellow G-type giant about 155 light-years away, sun-coloured but far older and more swollen. The glow reaching us tonight set out a century and a half ago, from a sun that has already exhausted the hydrogen in its core and is drifting toward the closing acts of stellar life.

Where it is and when to see it

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

From London it culminates about 62° above the horizon.
From New York it culminates about 73° above the horizon.
From Sydney it culminates about 33° above the horizon.

It can be seen from anywhere north of 67° S.

It ranks no. 17 in brightness among the 74 stars of Gemini in our catalogue. To find it, start from Pollux, the brightest: it lies about 23° away (a fist at arm's length covers about 10°).

The light you see today left it about 160 years ago.

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Astronomical data for 1 Geminorum

Constellation: Gemini
Apparent magnitude: 4.16
Distance: 155.1 light years
Coordinates (J2000): RA 91.030° · Dec 23.263°
Catalogue: HIP 28734 · HD 41116

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Other stars in Gemini

Gemini has 74 stars in Stelvia's catalogue. Here are a few of them.

See all 74 stars in Gemini