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Uncommon variable star 29 EP

HD 70938

RA 126.1161° · Dec -8.5202° · star

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Score breakdown

· 5 badges
29 pts · Uncommon
Uncommon 34 pts → Rare
  • Strongly variable +10
  • Red dwarf +6
  • Variable star +5
  • Cool red M-type star +5
  • A named variable star +3
Total score 29

5 more points to reach Rare.

Badges

  • Variable star · +5
  • Cool red M-type star · +5
  • Red dwarf · +6
  • Strongly variable · +10
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads Mb — an M-type red star — and M stars are the silent majority: roughly three of every four stars in the galaxy are one.
  • 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 7.6 it is just past naked-eye reach — ordinary binoculars will pull it in, 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.

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.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 4110 K, against the Sun's 5778 K.

What's in a name

  • Its catalogue. The HD number is from the Henry Draper Catalogue, in which Annie Jump Cannon personally classified the spectra of nearly 400,000 stars — still the largest such feat by one person.

Properties

absmag
-12.42
bv
1.305
constellation
Hya
luminosity
8090958.9918
mag
7.58
name
HD 70938
spect
Mb
var amplitude
0.62
var designation
FK
var max
7.275
var min
7.895

About HD 70938

HD 70938 is an uncommon variable star. It sits in the constellation Hya, shines at apparent magnitude 7.58 and has spectral type Mb.

Its spectrum reads Mb — an M-type red star — and M stars are the silent majority: roughly three of every four stars in the galaxy are one.

How to see it

Look for HD 70938 in the constellation Hya. At apparent magnitude 7.58, it is an easy target for binoculars.

Like any astronomical target, HD 70938 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 HD 70938 is an uncommon variable star

HD 70938 scores 29 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 5 points would lift it into a rarer tier.

That score comes from 5 science badges — Variable star, Cool red M-type star, Red dwarf, 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.