Key parameters at a glance

A radius of 2.35 Earth radii
A mass of 6.12 Earth masses
Surface gravity around 1.11 g
An orbital period of 2.940 days
Semi-major axis 0.0400 AU
Equilibrium temperature 1,256 K (983 °C)
Distance from Earth 2,702.50 light-years
Earth Similarity Index 0.199
Travel time at Voyager 1 speed 47,658,629 years

3 siblings around Kepler-172

Kepler-172 b shares its host star with 3 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
Kepler-172 b this	Sub-Neptune	2.35	6.12	2.940	1,256	2014
Kepler-172 c	Sub-Neptune	2.86	8.55	6.389	970	2014
Kepler-172 d	Sub-Neptune	2.25	5.69	14.627	736	2014
Kepler-172 e	Sub-Neptune	2.76	8.05	35.119	550	2014

Kepler-172 b Planet Profile

Physical Specs

Radius

2.35 R⊕

Radius (Jupiter)

0.210 R♃

Mass

6.12 M⊕

Mass (Jupiter)

0.019 M♃

Density

2.59 g/cm³

Surface Gravity

1.11 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.199

HZ Position Inner

Controversial No

Discovery

Year 2014

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1416of 1978

top 71.5%

This planet

2.35R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

HD 158259 f 2.35 R⊕ Kepler-216 b 2.35 R⊕ Kepler-306 c 2.35 R⊕

Metric	Earth	Kepler-172 b	Jupiter
Radius (R⊕)	1.00	2.35	11.21
Mass (M⊕)	1.00	6.12	317.83
Density (g/cm³)	5.51	2.59	1.33
Surface Gravity (g)	1.00	1.11	2.53
Insolation (S⊕)	1.00	639.48	0.037

Star Catalogue Identifiers

TIC

TIC 237157751

Gaia DR2

Gaia DR2 2104506319750394624

Gaia DR3

Gaia DR3 2104506319750394624

System

Kepler-172

Percentile among Sub-Neptune cohort

Radius 2.350 R⊕ · percentile 28 / cohort 1978

Mass 6.120 M⊕ · percentile 27 / cohort 1978

Orbital period 2.94 d · percentile 4 / cohort 1946

Distance 828.59 pc · percentile 67 / cohort 1975

ESI 0.199 · percentile 7 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

2.940 days

Semi-major axis

0.0400 AU

Eccentricity

0.000

Inclination

80.64 °

Year Length

A year here lasts approximately 2.94 Earth days (0.8% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0400 AU.

Transit Fingerprint

Depth

0.047 %

Duration

2.595 h

Impact parameter b

0.140

Rp / R★

0.020115

Transit midpoint (BJD)

2,455,002.9034

Photometric dip

Transit produces a flux drop of 472 ppm lasting ≈ 2.60 h.

Extended Orbital Architecture

Planet / star radius ratio

0.020115

Semi-major axis / stellar radius

8.984

Impact parameter (b)

0.140

Transit mid-time (BJD)

2,455,002.9034

Angular separation (arcsec)

0.04830

Eq. Temperature

1,256K

(983 °C)

Insolation (S⊕)

639.48

Earth = 1.00

Earth Similarity (ESI)

0.199

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.

Discovery Paper

Primary reference

Rowe et al. 2014

Instrument

Kepler CCD Array

Publication

2014-03

Observation locale

Space

Discovery cohort

Planets confirmed in 2014 at Kepler (12 shown).

Kepler-186 e · Super-Earth Kepler-395 c · Super-Earth Kepler-220 e · Super-Earth Kepler-249 d · Super-Earth Kepler-296 f · Super-Earth Kepler-367 c · Rocky Terrestrial Kepler-296 e · Super-Earth Kepler-155 c · Sub-Neptune Kepler-138 d · Super-Earth Kepler-333 c · Rocky Terrestrial Kepler-331 d · Super-Earth Kepler-267 d · Sub-Neptune

Host System: Kepler-172

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,526 K — cooler than the Sun (5,778 K)

Estimated Age

2.69 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.085 R☉

Stellar Mass

1.081 M☉

Metallicity [Fe/H]

0.39

Extended Stellar Properties

Surface gravity (log g)

4.375 dex

Stellar density

0.970 g/cm³

Metallicity ratio

[Fe/H]

Distance

828.59 parsec

Light-years 2,702.50 ly

V-band magnitude

14.70 mag

Voyager-speed travel 47,658,629 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

1.178 mas

Total Proper Motion

4.572 mas/yr

PM Right Ascension

0.84 mas/yr

PM Declination

4.49 mas/yr

Galactic Cartesian (pc)

x = 0.172 · y = -0.725 · z = 0.667

Equatorial (J2000)

RA 283.36841° · Dec 41.82184°

Galactic ℓ, b

71.607° · 17.348°

Ecliptic λ, β

293.303° · 64.183°

HTM-20 index

1365781898