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Rare exoplanet 41 EP

HD 20781 b

RA 50.0140° · Dec -28.7841° · exoplanet

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Score breakdown

· 4 badges
41 pts · Rare
Rare 46 pts → Epic
  • Earth-sized +16
  • Richly packed system +14
  • Multi-planet system +6
  • Confirmed exoplanet +5
Total score 41

5 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Earth-sized · +16
  • Multi-planet system · +6
  • Richly packed system · +14

Trivia

What makes it special

  • Packed system. Crammed into a system of five or more planets.

Could we get there?

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

Getting there

  • Aboard Voyager 1. ≈ 2.1 million years at Voyager 1's speed (17 km/s).
  • Fastest probe ever. ≈ 183.2 thousand years even at the Parker Solar Probe's 192 km/s.
  • At 10% light speed. ≈ 1173 years in a starship at a tenth of light speed.
  • Distance. 117 light-years from Earth.

Look-back time

  • Look-back time. The light you'd see left around the year 1909.

Saying hello

  • Say hello. A radio message and its reply would take 235 years round-trip.

Standing on it

  • A year here. A full year lasts just 5.3 Earth days.

By the numbers

  • Size. About 1.2× the width of Earth.
  • Mass. About 1.9× the mass of Earth.
  • Your weight. You'd weigh about 1.3× your Earth weight standing here.
  • Temperature. Around 733°C — hotter than a self-cleaning oven.

How we found it

  • Discovery. Found by La Silla Observatory using the radial velocity method.

Cosmic context

  • Crowded system. One of at least 5 planets orbiting its star.

Properties

density gcc
5.99
discovery facility
La Silla Observatory
discovery method
Radial Velocity
dist ly
117.3232
eccentricity
0.1
eq temp k
1006.1
insolation
175.0994
mass earth
1.93
name
HD 20781 b
orbital period days
5.3135
radius earth
1.21
sys num planets
5

About HD 20781 b

HD 20781 b is a rare exoplanet. It lies about 117.3 light-years from Earth, has an equilibrium temperature near 1,006 K, spans roughly 1.21 Earth radii and weighs about 1.93 Earth masses.

Crammed into a system of five or more planets.

How to see it

Like any astronomical target, HD 20781 b 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 20781 b is a rare exoplanet

HD 20781 b scores 41 points on Spacedle's rarity scale, which places it in the rare tier. Another 5 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, Earth-sized, Multi-planet system and Richly packed system — 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.

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Sky imagery and survey data courtesy of Aladin Lite & CDS, Strasbourg. Object data from the NASA Exoplanet Archive, JPL Small-Body Database, and the ATNF Pulsar Catalogue.