Star profile

Phi Persei

Variable star

3D likeness based on its real data · class B · ~15,000 K

What is Phi Persei

Phi Persei is one of the great Be variables of the sky: a blue star spinning at 440 km/s along its equator, so distorted by its own rotation that it has wrapped a disc of gas around its waist. A hot subdwarf companion travels with it, a shared relic of a violent binary history seven hundred light-years away.

Where it is and when to see it

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

From London it never sets and culminates about 89° up.
From New York it never sets and culminates about 80° up.
From Sydney it culminates about 5° above the horizon.

It can be seen from anywhere north of 39° S.

It ranks no. 15 in brightness among the 99 stars of Perseus in our catalogue. To find it, start from Mirfak, the brightest: it lies about 16° away (a fist at arm's length covers about 10°).

The light you see today left it about 720 years ago.

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Astronomical data for Phi Persei

Constellation: Perseus
Apparent magnitude: 4.01
Distance: 718.5 light years
Coordinates (J2000): RA 25.915° · Dec 50.689°
Catalogue: HIP 8068 · HD 10516

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Other stars in Perseus

Perseus has 99 stars in Stelvia's catalogue. Here are a few of them.

See all 99 stars in Perseus