Key parameters at a glance

A radius of 2.48 Earth radii
A mass of 6.71 Earth masses
Surface gravity around 1.09 g
An orbital period of 11.810 days
Semi-major axis 0.0910 AU
Equilibrium temperature 676 K (403 °C)
Distance from Earth 1,611.18 light-years
Earth Similarity Index 0.376
Travel time at Voyager 1 speed 28,413,238 years

K2-15 b Planet Profile

Physical Specs

Radius

2.48 R⊕

Radius (Jupiter)

0.221 R♃

Mass

6.71 M⊕

Mass (Jupiter)

0.021 M♃

Density

2.42 g/cm³

Surface Gravity

1.09 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.376

HZ Position Inner

Controversial No

Discovery

Year 2015

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1212of 1978

top 61.2%

This planet

2.48R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-1030 b 2.48 R⊕ Kepler-256 d 2.48 R⊕ Kepler-266 b 2.48 R⊕

Metric	Earth	K2-15 b	Jupiter
Radius (R⊕)	1.00	2.48	11.21
Mass (M⊕)	1.00	6.71	317.83
Density (g/cm³)	5.51	2.42	1.33
Surface Gravity (g)	1.00	1.09	2.53
Insolation (S⊕)	1.00	48.00	0.037

Star Catalogue Identifiers

TIC

TIC 366696612

Gaia DR2

Gaia DR2 3896271842760486272

Gaia DR3

Gaia DR3 3896271842760486272

System

K2-15

Percentile among Sub-Neptune cohort

Radius 2.480 R⊕ · percentile 38 / cohort 1978

Mass 6.710 M⊕ · percentile 36 / cohort 1978

Orbital period 11.81 d · percentile 41 / cohort 1946

Distance 493.99 pc · percentile 47 / cohort 1975

ESI 0.376 · percentile 47 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

11.810 days

Semi-major axis

0.0910 AU

Eccentricity

—

Inclination

— °

Year Length

A year here lasts approximately 11.81 Earth days (3.2% of a terrestrial year) at a mean orbital distance of 0.0910 AU.

Transit Fingerprint

Depth

0.121 %

Duration

2.402 h

Impact parameter b

0.510

Rp / R★

0.035400

Transit midpoint (BJD)

2,456,811.8509

Photometric dip

Transit produces a flux drop of 1,210 ppm lasting ≈ 2.40 h.

Extended Orbital Architecture

Planet / star radius ratio

0.035400

Semi-major axis / stellar radius

28.840

Impact parameter (b)

0.510

Transit mid-time (BJD)

2,456,811.8509

Angular separation (arcsec)

0.18400

Eq. Temperature

676K

(403 °C)

Insolation (S⊕)

48.00

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

Montet et al. 2015

Instrument

Kepler CCD Array

Publication

2015-08

Observation locale

Space

Discovery cohort

Planets confirmed in 2015 at K2 (12 shown).

K2-18 b · Sub-Neptune K2-9 b · Sub-Neptune K2-3 d · Super-Earth K2-3 c · Super-Earth K2-21 c · Sub-Neptune K2-5 c · Sub-Neptune K2-13 b · Super-Earth K2-3 b · Sub-Neptune K2-17 b · Sub-Neptune K2-21 b · Super-Earth K2-16 c · Sub-Neptune K2-5 b · Super-Earth

Host System: K2-15

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,131 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.680 R☉

Stellar Mass

0.720 M☉

Metallicity [Fe/H]

-0.46

Extended Stellar Properties

Surface gravity (log g)

4.571 dex

Stellar density

1.891 g/cm³

Metallicity ratio

[Fe/H]

Distance

493.99 parsec

Light-years 1,611.18 ly

V-band magnitude

14.76 mag

Voyager-speed travel 28,413,238 yr

Multi-band Host Photometry — 17 bands

Astrometric Data

Parallax

1.996 mas

Total Proper Motion

53.582 mas/yr

PM Right Ascension

-49.17 mas/yr

PM Declination

-21.29 mas/yr

Galactic Cartesian (pc)

x = -0.997 · y = 0.033 · z = 0.074

Equatorial (J2000)

RA 178.11057° · Dec 4.25466°

Galactic ℓ, b

268.742° · 63.141°

Ecliptic λ, β

176.570° · 3.152°

HTM-20 index

-1234227810