About HD 164509 b
HD 164509 b is a common exoplanet. It lies about 173.2 light-years from Earth, has an equilibrium temperature near 319 K, spans roughly 14.3 Earth radii and weighs about 140.8 Earth masses.
So low-density it would float on water.
Common exoplanet 21 EP
HD 164509 b
RA 270.3801° · Dec 0.1045° · exoplanet
Score breakdown
· 3 badgesCommon 24 pts → Uncommon
- Puffy low-density world +12
- Confirmed exoplanet +5
- Gas giant +4
Total score 21
3 more points to reach Uncommon.
Badges
- Confirmed exoplanet · +5
- Gas giant · +4
- Puffy low-density world · +12
Trivia
What makes it special
- Cotton-candy planet. So low-density it would float on water.
Could we get there?
- Verdict. Hopelessly far for any craft humanity can build today.
Getting there
- Aboard Voyager 1. ≈ 3 million years at Voyager 1's speed (17 km/s).
- Fastest probe ever. ≈ 270.5 thousand years even at the Parker Solar Probe's 192 km/s.
- At 10% light speed. ≈ 1732 years in a starship at a tenth of light speed.
- Distance. 173 light-years from Earth.
Look-back time
- Look-back time. The light you'd see left around the year 1853.
Saying hello
- Say hello. A radio message and its reply would take 346 years round-trip.
Standing on it
- A year here. A full year lasts just 280 Earth days.
By the numbers
- Size. About 14.3× the width of Earth.
- Volume. About 2924 Earths could fit inside it.
- Mass. Roughly 141× Earth's mass — about 0.4 Jupiters.
- Your weight. You'd weigh about 0.7× your Earth weight standing here.
- Density. Less dense than water — drop it in a big enough ocean and it would float.
- Temperature. A surprisingly temperate 46°C average.
How we found it
- Discovery. Found by W. M. Keck Observatory using the radial velocity method.
Properties
- density gcc
- 0.265
- discovery facility
- W. M. Keck Observatory
- discovery method
- Radial Velocity
- dist ly
- 173.2276
- eccentricity
- 0.238
- eq temp k
- 319.12
- insolation
- 1.7417
- mass earth
- 140.7987
- name
- HD 164509 b
- orbital period days
- 280.17
- radius earth
- 14.3
- sys num planets
- 1
How to see it
Like any astronomical target, HD 164509 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 164509 b is a common exoplanet
HD 164509 b scores 21 points on Spacedle's rarity scale, which places it in the common tier. Another 3 points would lift it into a rarer tier.
That score comes from 3 science badges — Confirmed exoplanet, Gas giant and Puffy low-density world — 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.