Common variable star 20 EP

HD 258857

RA 97.7962° · Dec 5.8769° · star

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Score breakdown

· 5 badges

20 pts · Common

Common 22 pts → Uncommon

Variable star +5
Subgiant (leaving the main sequence) +5
Gently variable +4
Orange K-type star +3
A named variable star +3

Total score 20

2 more points to reach Uncommon.

Badges

Variable star · +5
Orange K-type star · +3
Subgiant (leaving the main sequence) · +5
Gently variable · +4
A named variable star · +3

Trivia

What it actually is

Spectral class. Its spectrum reads K2IV-V — a K-type star. Orange K dwarfs are the marathon runners of the galaxy, burning steadily for tens of billions of years.
Where it is in life. It is a subgiant, caught in the act of leaving the main sequence as the hydrogen in its core runs out.
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 8.9 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Monoceros.
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 December — that's when to go looking.

Could we get there?

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

Properties

absmag: 6.477
bv: 0.911
constellation: Mon
dist ly: 101.3853
luminosity: 0.2235
mag: 8.94
name: HD 258857
spect: K2IV-V
var amplitude: 0.08
var designation: V848
var max: 8.887
var min: 8.967

Nearby objects

About HD 258857

HD 258857 is a common variable star. It lies about 101.4 light-years from Earth, sits in the constellation Mon, shines at apparent magnitude 8.94 and has spectral type K2IV-V.

Its spectrum reads K2IV-V — a K-type star. Orange K dwarfs are the marathon runners of the galaxy, burning steadily for tens of billions of years.

How to see it

Look for HD 258857 in the constellation Mon. At apparent magnitude 8.94, it is an easy target for binoculars.

Like any astronomical target, HD 258857 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 258857 is a common variable star

HD 258857 scores 20 points on Spacedle's rarity scale, which places it in the common tier. Another 2 points would lift it into a rarer tier.

That score comes from 5 science badges — Variable star, Orange K-type star, Subgiant (leaving the main sequence), 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.