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Common variable star 21 EP

HIP 91201

RA 279.0664° · Dec 4.3982° · star

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Score breakdown

· 5 badges
21 pts · Common
Common 22 pts → Uncommon
  • Giant star +6
  • Variable star +5
  • Gently variable +4
  • Yellow-white F-type star +3
  • A named variable star +3
Total score 21

1 more point to reach Uncommon.

Badges

  • Variable star · +5
  • Yellow-white F-type star · +3
  • Giant star · +6
  • Gently variable · +4
  • A named variable star · +3

Trivia

Hard to believe

  • True brightness. It pours out about 1.3 million times as much light as the Sun. It only looks ordinary because it is so far away.

What it actually is

  • Spectral class. Its spectrum reads F5IIIvar — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
  • Where it is in life. It is a giant. It has already exhausted its core hydrogen and swollen up enormously in response.
  • It changes. This star does not hold still: its brightness rises and falls on a rhythm of hours, days or years, either pulsing in size or being eclipsed by a companion.

Find it in the sky

  • How to spot it. At magnitude 9.5 you'll want a small backyard telescope, over in Serpens.
  • Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
  • Best time of year. It stands highest in the middle of the night around June — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out orange (B−V 1.3) — cooler than the Sun, and the kind of star that burns steadily for tens of billions of years.

Properties

absmag
-10.47
bv
1.3
constellation
Ser
luminosity
1342764.9611
mag
9.53
name
HIP 91201
spect
F5IIIvar
var amplitude
0.43
var designation
BQ
var max
9.277
var min
9.707

Nearby objects

About HIP 91201

HIP 91201 is a common variable star. It sits in the constellation Ser, shines at apparent magnitude 9.53 and has spectral type F5IIIvar.

Its spectrum reads F5IIIvar — an F-type star — a little hotter, whiter and shorter-lived than the Sun.

How to see it

Look for HIP 91201 in the constellation Ser. At apparent magnitude 9.53, a small backyard telescope will bring it into view.

Like any astronomical target, HIP 91201 is best seen from a dark site away from city lights, and when it is above the horizon depends on your latitude and the time of year. The visibility panel above works out tonight's viewing window for your saved location.

Why HIP 91201 is a common variable star

HIP 91201 scores 21 points on Spacedle's rarity scale, which places it in the common tier. Another 1 point would lift it into a rarer tier.

That score comes from 5 science badges — Variable star, Yellow-white F-type star, Giant star, Gently variable and A named variable star — each earned for a real, measurable property of the object. Rarity on Spacedle is never random: the more remarkable an object's astrophysics, the more badges it collects, the higher it scores, and the rarer it ranks.