Key parameters at a glance

A radius of 1.04 Earth radii
A mass of 1.12 Earth masses
Surface gravity around 1.04 g
An orbital period of 8.239 days
Semi-major axis 0.0570 AU
Distance from Earth 90.66 light-years
Earth Similarity Index 0.991
Travel time at Voyager 1 speed 1,598,742 years
Almost certainly tidally locked to its host star given the close orbit

K2-129 b Planet Profile

Physical Specs

Radius

1.04 R⊕

Radius (Jupiter)

0.093 R♃

Mass

1.12 M⊕

Mass (Jupiter)

0.004 M♃

Density

5.47 g/cm³

Surface Gravity

1.04 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.991

HZ Position Inner

Controversial No

Discovery

Year 2017

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#288of 570

top 50.4%

This planet

1.04R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Kepler-1409 b 1.04 R⊕ EPIC 201841433 b 1.04 R⊕ Kepler-1578 b 1.04 R⊕

Metric	Earth	K2-129 b	Jupiter
Radius (R⊕)	1.00	1.04	11.21
Mass (M⊕)	1.00	1.12	317.83
Density (g/cm³)	5.51	5.47	1.33
Surface Gravity (g)	1.00	1.04	2.53
Insolation (S⊕)	1.00	4.50	0.037

Star Catalogue Identifiers

TIC

TIC 2468648

Gaia DR2

Gaia DR2 6769308026926349056

Gaia DR3

Gaia DR3 6769308026926349056

System

K2-129

Percentile among Rocky Terrestrial cohort

Radius 1.040 R⊕ · percentile 48 / cohort 570

Mass 1.120 M⊕ · percentile 43 / cohort 570

Orbital period 8.24 d · percentile 74 / cohort 567

Distance 27.80 pc · percentile 12 / cohort 566

ESI 0.991 · percentile 99 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

8.239 days

Semi-major axis

0.0570 AU

Eccentricity

0.130

Inclination

89.21 °

Year Length

A year here lasts approximately 8.24 Earth days (2.3% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0570 AU.

Transit Fingerprint

Depth

0.086 %

Duration

1.512 h

Rp / R★

0.026595

Transit midpoint (BJD)

2,457,335.0090

Photometric dip

Transit produces a flux drop of 858 ppm lasting ≈ 1.51 h.

Extended Orbital Architecture

Planet / star radius ratio

0.026595

Semi-major axis / stellar radius

34.370

Transit mid-time (BJD)

2,457,335.0090

Long. of periastron (ω)

39.89°

Angular separation (arcsec)

2.05000

Eq. Temperature

—

Insolation (S⊕)

4.50

Earth = 1.00

Earth Similarity (ESI)

0.991

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water). Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

Dressing et al. 2017

Instrument

Kepler CCD Array

Publication

2017-11

Observation locale

Space

Discovery cohort

Planets confirmed in 2017 at K2 (12 shown).

K2-130 b · Super-Earth K2-133 b · Super-Earth K2-128 b · Super-Earth K2-133 c · Super-Earth K2-116 b · Rocky Terrestrial K2-125 b · Sub-Neptune K2-118 b · Sub-Neptune K2-136 d · Super-Earth K2-123 b · Sub-Neptune K2-136 c · Sub-Neptune K2-124 b · Sub-Neptune K2-117 c · Sub-Neptune

Host System: K2-129

Spectral Class

M-type red dwarf

Effective Temperature

3,459 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.360 R☉

Stellar Mass

0.360 M☉

Metallicity [Fe/H]

—

Distance

27.80 parsec

Light-years 90.66 ly

V-band magnitude

13.64 mag

Voyager-speed travel 1,598,742 yr

Multi-band Host Photometry — 8 bands

Astrometric Data

Parallax

35.948 mas

Total Proper Motion

316.273 mas/yr

PM Right Ascension

51.44 mas/yr

PM Declination

-312.06 mas/yr

Galactic Cartesian (pc)

x = 0.296 · y = -0.852 · z = -0.433

Equatorial (J2000)

RA 289.14855° · Dec -25.64632°

Galactic ℓ, b

12.144° · -16.574°

Ecliptic λ, β

287.226° · -3.345°

HTM-20 index

-1171692629