About HD 1397 b
HD 1397 b is a common exoplanet. It lies about 259.5 light-years from Earth, has an equilibrium temperature near 1,228 K, spans roughly 11.5 Earth radii and weighs about 131.9 Earth masses.
About 11.5× the width of Earth.
Common exoplanet 23 EP
HD 1397 b
RA 4.4472° · Dec -66.3589° · exoplanet
Score breakdown
· 4 badgesCommon 24 pts → Uncommon
- Hot Jupiter +10
- Confirmed exoplanet +5
- Gas giant +4
- Found by TESS +4
Total score 23
1 more point to reach Uncommon.
Badges
- Confirmed exoplanet · +5
- Gas giant · +4
- Hot Jupiter · +10
- Found by TESS · +4
Trivia
Could we get there?
- Verdict. Hopelessly far for any craft humanity can build today.
Getting there
- Aboard Voyager 1. ≈ 4.6 million years at Voyager 1's speed (17 km/s).
- Fastest probe ever. ≈ 405.2 thousand years even at the Parker Solar Probe's 192 km/s.
- At 10% light speed. ≈ 2595 years in a starship at a tenth of light speed.
- Distance. 260 light-years from Earth.
Look-back time
- Look-back time. The light you'd see left around the year 1766.
Saying hello
- Say hello. A radio message and its reply would take 519 years round-trip.
Standing on it
- A year here. A full year lasts just 11.5 Earth days.
By the numbers
- Size. About 11.5× the width of Earth.
- Volume. About 1521 Earths could fit inside it.
- Mass. Roughly 132× Earth's mass — about 0.4 Jupiters.
- Your weight. You'd weigh about 1.0× your Earth weight standing here.
- Density. Less dense than water — drop it in a big enough ocean and it would float.
- Temperature. Around 955°C — hotter than a self-cleaning oven.
How we found it
- Discovery. Found by Transiting Exoplanet Survey Satellite (TESS) using the transit method.
Properties
- density gcc
- 0.477
- discovery facility
- Transiting Exoplanet Survey Satellite (TESS)
- discovery method
- Transit
- dist ly
- 259.523
- eccentricity
- 0.251
- eq temp k
- 1228.3
- insolation
- 356
- mass earth
- 131.8995
- name
- HD 1397 b
- orbital period days
- 11.5353
- radius earth
- 11.5004
- sys num planets
- 1
How to see it
Like any astronomical target, HD 1397 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 1397 b is a common exoplanet
HD 1397 b scores 23 points on Spacedle's rarity scale, which places it in the common tier. Another 1 point would lift it into a rarer tier.
That score comes from 4 science badges — Confirmed exoplanet, Gas giant, Hot Jupiter and Found by TESS — 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.