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Uncommon exoplanet 32 EP

HR 858 d

RA 42.9850° · Dec -30.8141° · exoplanet

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Score breakdown

· 5 badges
32 pts · Uncommon
Uncommon 34 pts → Rare
  • Two suns in its sky +12
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Sub-Neptune +5
  • Found by TESS +4
Total score 32

2 more points to reach Rare.

Badges

  • Confirmed exoplanet · +5
  • Sub-Neptune · +5
  • Multi-planet system · +6
  • Found by TESS · +4
  • Two suns in its sky · +12

Trivia

What it actually is

  • Hugging its star. It orbits closer to its star than Mercury does to the Sun, completing a lap in less time than Mercury takes.
  • What it is made of. Its density says rock, though lighter than Earth's mix: probably less iron, or a thick shell of water and ice over the top.
  • Crowded system. One of at least 3 planets orbiting its star.

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 6.4 it is just past naked-eye reach — ordinary binoculars will pull it in.
  • 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 November — that's when to go looking.

Could we get there?

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

Properties

density gcc
4.9
diameter km
25525.1562
discovery facility
Transiting Exoplanet Survey Satellite (TESS)
discovery method
Transit
discovery year
2019
dist ly
104.2525
eccentricity
0
eq temp k
1061
host star teff
6354
inclination
87.72
insolation
217
mag
6.38
mass earth
7.1
multi star system
yes
name
HR 858 d
orbital period days
11.2305
radius earth
2.001
semi major au
0.1046
spect
F6 V
sys num planets
3
sys num stars
2

About HR 858 d

HR 858 d is an uncommon exoplanet. It lies about 104.3 light-years from Earth, shines at apparent magnitude 6.38, has spectral type F6 V and has an equilibrium temperature near 1,061 K.

It orbits closer to its star than Mercury does to the Sun, completing a lap in less time than Mercury takes.

How to see it

At apparent magnitude 6.38, it is an easy target for binoculars.

Like any astronomical target, HR 858 d 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 858 d is an uncommon exoplanet

HR 858 d scores 32 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 2 points would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, Sub-Neptune, Multi-planet system, Found by TESS and Two suns in its sky — 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.