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Uncommon variable star 23 EP

HIP 40186

RA 123.1326° · Dec 2.8347° · 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 96.4 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 A-F — 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 12.4 it is far too faint for the eye: this one belongs to cameras and long exposures, over in Hydra.
  • 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 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
-7.63
constellation
Hya
luminosity
98174.7943
mag
12.37
name
HIP 40186
spect
A-F
var amplitude
1.32
var designation
DD
var max
11.474
var min
12.794

About HIP 40186

HIP 40186 is an uncommon variable star. It sits in the constellation Hya, shines at apparent magnitude 12.37 and has spectral type A-F.

Its spectrum reads A-F — 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 40186 in the constellation Hya. At apparent magnitude 12.37, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, HIP 40186 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 40186 is an uncommon variable star

HIP 40186 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.