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Common exoplanet 19 EP

alf Tau b

RA 68.9802° · Dec 16.5092° · exoplanet

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Score breakdown

· 3 badges
19 pts · Common
Common 24 pts → Uncommon
  • Hot Jupiter +10
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 19

5 more points to reach Uncommon.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Hot Jupiter · +10

Trivia

Could we get there?

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

Getting there

  • Aboard Voyager 1. ≈ 1.2 million years at Voyager 1's speed (17 km/s).
  • Fastest probe ever. ≈ 104.1 thousand years even at the Parker Solar Probe's 192 km/s.
  • At 10% light speed. ≈ 666 years in a starship at a tenth of light speed.
  • Distance. 66.6 light-years from Earth.

Look-back time

  • Look-back time. The light you'd see left around the year 1959.

Saying hello

  • Say hello. A radio message and its reply would take 133 years round-trip.

Standing on it

  • A year here. A full year lasts just 629 Earth days.

By the numbers

  • Size. About 12.7× the width of Earth.
  • Volume. About 2048 Earths could fit inside it.
  • Mass. Roughly 2056× Earth's mass — about 6.5 Jupiters.
  • Your weight. You'd weigh about 12.7× your Earth weight standing here.
  • Temperature. Around 814°C — hotter than a self-cleaning oven.

How we found it

  • Discovery. Found by Multiple Observatories using the radial velocity method.

Properties

density gcc
5.52
discovery facility
Multiple Observatories
discovery method
Radial Velocity
dist ly
66.6441
eccentricity
0.1
eq temp k
1086.77
insolation
220.442
mass earth
2056.3601
name
alf Tau b
orbital period days
628.96
radius earth
12.7
sys num planets
1

About alf Tau b

alf Tau b is a common exoplanet. It lies about 66.6 light-years from Earth, has an equilibrium temperature near 1,087 K, spans roughly 12.7 Earth radii and weighs about 2,056.36 Earth masses.

About 12.7× the width of Earth.

How to see it

Like any astronomical target, alf Tau 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 alf Tau b is a common exoplanet

alf Tau b scores 19 points on Spacedle's rarity scale, which places it in the common tier. Another 5 points would lift it into a rarer tier.

That score comes from 3 science badges — Confirmed exoplanet, Gas giant and Hot Jupiter — 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.

spacedle A daily roll through the real universe. © 2026 spacedle. Buy me a coffee

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.