Key parameters at a glance

A radius of 2.32 Earth radii
A mass of 5.99 Earth masses
Surface gravity around 1.11 g
An orbital period of 36.292 days
Semi-major axis 0.2226 AU
Equilibrium temperature 694 K (421 °C)
Distance from Earth 5,274.17 light-years
Earth Similarity Index 0.376
Travel time at Voyager 1 speed 93,009,997 years

Kepler-1255 b Planet Profile

Physical Specs

Radius

2.32 R⊕

Radius (Jupiter)

0.207 R♃

Mass

5.99 M⊕

Mass (Jupiter)

0.019 M♃

Density

2.64 g/cm³

Surface Gravity

1.11 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.376

HZ Position Inner

Controversial No

Discovery

Year 2016

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1469of 1978

top 74.2%

This planet

2.32R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-321 c 2.32 R⊕ K2-28 b 2.32 R⊕ Kepler-1208 b 2.32 R⊕

Metric	Earth	Kepler-1255 b	Jupiter
Radius (R⊕)	1.00	2.32	11.21
Mass (M⊕)	1.00	5.99	317.83
Density (g/cm³)	5.51	2.64	1.33
Surface Gravity (g)	1.00	1.11	2.53
Insolation (S⊕)	1.00	39.67	0.037

Star Catalogue Identifiers

TIC

TIC 271538318

Gaia DR2

Gaia DR2 2077911332502996224

Gaia DR3

Gaia DR3 2077911332502996224

System

Kepler-1255

Percentile among Sub-Neptune cohort

Radius 2.320 R⊕ · percentile 25 / cohort 1978

Mass 5.990 M⊕ · percentile 24 / cohort 1978

Orbital period 36.29 d · percentile 78 / cohort 1946

Distance 1,617.07 pc · percentile 94 / cohort 1975

ESI 0.376 · percentile 47 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

36.292 days

Semi-major axis

0.2226 AU

Eccentricity

0.000

Inclination

90.00 °

Year Length

A year here lasts approximately 36.29 Earth days (9.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.2226 AU.

Transit Fingerprint

Depth

0.037 %

Duration

8.181 h

Impact parameter b

0.739

Rp / R★

0.019263

Transit midpoint (BJD)

2,454,965.1781

Photometric dip

Transit produces a flux drop of 375 ppm lasting ≈ 8.18 h.

Extended Orbital Architecture

Planet / star radius ratio

0.019263

Semi-major axis / stellar radius

34.420

Impact parameter (b)

0.739

Transit mid-time (BJD)

2,454,965.1781

Angular separation (arcsec)

0.13800

Eq. Temperature

694K

(421 °C)

Insolation (S⊕)

39.67

Earth = 1.00

Earth Similarity (ESI)

0.376

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.

Discovery Paper

Primary reference

Morton et al. 2016

Instrument

Kepler CCD Array

Publication

2016-05

Observation locale

Space

Discovery cohort

Planets confirmed in 2016 at Kepler (12 shown).

Kepler-1512 b · Rocky Terrestrial Kepler-1410 b · Super-Earth Kepler-560 b · Super-Earth Kepler-1389 b · Super-Earth Kepler-1450 b · Super-Earth Kepler-1544 b · Super-Earth Kepler-1459 b · Super-Earth Kepler-1638 b · Super-Earth Kepler-737 b · Super-Earth Kepler-1185 b · Super-Earth Kepler-1178 b · Rocky Terrestrial Kepler-1040 b · Sub-Neptune

Host System: Kepler-1255

Spectral Class

F-type yellow-white

Effective Temperature

6,018 K — hotter than the Sun (5,778 K)

Estimated Age

3.55 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.120 R☉

Stellar Mass

1.080 M☉

Metallicity [Fe/H]

0.02

Extended Stellar Properties

Surface gravity (log g)

4.370 dex

Stellar density

0.540 g/cm³

Metallicity ratio

[Fe/H]

Distance

1,617.07 parsec

Light-years 5,274.17 ly

V-band magnitude

15.31 mag

Voyager-speed travel 93,009,997 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

0.591 mas

Total Proper Motion

1.667 mas/yr

PM Right Ascension

1.63 mas/yr

PM Declination

-0.35 mas/yr

Galactic Cartesian (pc)

x = 0.313 · y = -0.664 · z = 0.678

Equatorial (J2000)

RA 295.23926° · Dec 42.72648°

Galactic ℓ, b

76.211° · 9.742°

Ecliptic λ, β

312.671° · 62.477°

HTM-20 index

-1563045040