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Rare variable star 45 EP

HR 2788

RA 109.8674° · Dec -16.3952° · star

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Score breakdown

· 7 badges
45 pts · Rare
Rare 50 pts → Epic
  • Fades out of naked-eye view +16
  • Naked-eye visible +8
  • Giant star +6
  • Variable star +5
  • Gently variable +4
  • Yellow-white F-type star +3
  • A named variable star +3
Total score 45

5 more points to reach Epic.

Badges

  • Variable star · +5
  • Naked-eye visible · +8
  • Yellow-white F-type star · +3
  • Giant star · +6
  • Gently variable · +4
  • Fades out of naked-eye view · +16
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads F2III/IV — 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.

Sense of scale

  • In perspective. Far away by human standards, yet still a local address inside the Milky Way's spiral arms.

Find it in the sky

  • How to spot it. At magnitude 5.7 you can see it with your own eyes from a dark site, over in Canis Major.
  • Southern sky. It rides the southern half of the sky — an easier target the further south you are.
  • Best time of year. It stands highest in the middle of the night around January — that's when to go looking.

Could we get there?

  • Verdict. Hopelessly far for any craft humanity can build today.

Properties

absmag
2.544
bv
0.346
constellation
CMa
dist ly
139.5021
luminosity
8.3637
mag
5.7
name
HR 2788
spect
F2III/IV
var amplitude
0.4
var designation
R
var max
5.684
var min
6.084

About HR 2788

HR 2788 is a rare variable star. It lies about 139.5 light-years from Earth, sits in the constellation CMa, shines at apparent magnitude 5.7 and has spectral type F2III/IV.

Its spectrum reads F2III/IV — an F-type star — a little hotter, whiter and shorter-lived than the Sun.

How to see it

Look for HR 2788 in the constellation CMa. At apparent magnitude 5.7, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, HR 2788 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 HR 2788 is a rare variable star

HR 2788 scores 45 points on Spacedle's rarity scale, which places it in the rare tier. Another 5 points would lift it into a rarer tier.

That score comes from 7 science badges — Variable star, Naked-eye visible, Yellow-white F-type star, Giant star, Gently variable, Fades out of naked-eye view 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.