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Common exoplanet 15 EP

HD 21693 c

RA 51.8040° · Dec -58.3233° · exoplanet

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Score breakdown

· 3 badges
15 pts · Common
Common 24 pts → Uncommon
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Neptune-like +4
Total score 15

9 more points to reach Uncommon.

Badges

  • Confirmed exoplanet · +5
  • Neptune-like · +4
  • Multi-planet system · +6

Trivia

Could we get there?

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

Getting there

  • Aboard Voyager 1. ≈ 1.9 million years at Voyager 1's speed (17 km/s).
  • Fastest probe ever. ≈ 169.4 thousand years even at the Parker Solar Probe's 192 km/s.
  • At 10% light speed. ≈ 1085 years in a starship at a tenth of light speed.
  • Distance. 108 light-years from Earth.

Look-back time

  • Look-back time. The light you'd see left around the year 1918.

Saying hello

  • Say hello. A radio message and its reply would take 217 years round-trip.

Standing on it

  • A year here. A full year lasts just 53.7 Earth days.

By the numbers

  • Size. About 4.3× the width of Earth.
  • Volume. About 81.7 Earths could fit inside it.
  • Mass. About 17.4× the mass of Earth.
  • Your weight. You'd weigh about 0.9× your Earth weight standing here.
  • Temperature. A scorching 219°C on average.

How we found it

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

Cosmic context

  • Crowded system. One of at least 2 planets orbiting its star.

Properties

density gcc
1.17
discovery facility
La Silla Observatory
discovery method
Radial Velocity
dist ly
108.4632
eccentricity
0.07
eq temp k
492.36
insolation
9.2712
mass earth
17.37
name
HD 21693 c
orbital period days
53.7357
radius earth
4.34
sys num planets
2

About HD 21693 c

HD 21693 c is a common exoplanet. It lies about 108.5 light-years from Earth, has an equilibrium temperature near 492 K, spans roughly 4.34 Earth radii and weighs about 17.37 Earth masses.

One of at least 2 planets orbiting its star.

How to see it

Like any astronomical target, HD 21693 c 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 21693 c is a common exoplanet

HD 21693 c scores 15 points on Spacedle's rarity scale, which places it in the common tier. Another 9 points would lift it into a rarer tier.

That score comes from 3 science badges — Confirmed exoplanet, Neptune-like and Multi-planet 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.