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Uncommon variable star 23 EP

HIP 39849

RA 122.1176° · Dec -16.5332° · star

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Score breakdown

· 4 badges
23 pts · Uncommon
Uncommon 34 pts → Rare
  • Strongly variable +10
  • Variable star +5
  • White A-type star +5
  • A named variable star +3
Total score 23

11 more points to reach Rare.

Badges

  • Variable star · +5
  • White A-type star · +5
  • Strongly variable · +10
  • A named variable star · +3

Trivia

Hard to believe

  • True brightness. It pours out about 207 thousand 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 A3.5 — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.
  • 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 11.5 you'll want a small backyard telescope, over in Puppis.
  • 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.

What's in a name

  • Its catalogue. The HIP number comes from Hipparcos, the ESA satellite that between 1989 and 1993 pinned down 118,000 stars precisely enough to triangulate their distances.

How we came to know it

  • Cosmic yardstick. Variable stars are how we measured the universe. In 1912 Henrietta Leavitt showed that a pulsating star's rhythm reveals its true brightness — turning these stars into distance markers.

Properties

absmag
-8.46
constellation
Pup
luminosity
210862.815
mag
11.54
name
HIP 39849
spect
A3.5
var amplitude
1.16
var designation
XX
var max
10.581
var min
11.741

About HIP 39849

HIP 39849 is an uncommon variable star. It sits in the constellation Pup, shines at apparent magnitude 11.54 and has spectral type A3.5.

Its spectrum reads A3.5 — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.

How to see it

Look for HIP 39849 in the constellation Pup. At apparent magnitude 11.54, a small backyard telescope will bring it into view.

Like any astronomical target, HIP 39849 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 39849 is an uncommon variable star

HIP 39849 scores 23 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 11 points would lift it into a rarer tier.

That score comes from 4 science badges — Variable star, White A-type star, Strongly 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.