Key parameters at a glance

A radius of 0.51 Earth radii
A mass of 99.20 Earth masses
Surface gravity around 381.39 g
An orbital period of 0.412 days
Semi-major axis 0.0080 AU
Equilibrium temperature 1,180 K (907 °C)
Distance from Earth 561.79 light-years
Earth Similarity Index 0.102
Travel time at Voyager 1 speed 9,907,120 years
Almost certainly tidally locked to its host star given the close orbit

KOI-4777.01 Planet Profile

Physical Specs

Radius

0.51 R⊕

Radius (Jupiter)

0.046 R♃

Mass

99.20 M⊕

Mass (Jupiter)

0.312 M♃

Density

— g/cm³

Surface Gravity

381.39 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.102

HZ Position Inner

Controversial No

Discovery

Year 2022

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#560of 570

top 98.1%

This planet

0.51R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Kepler-1489 c 0.51 R⊕ Kepler-1994 b 0.51 R⊕ Kepler-1308 b 0.52 R⊕

Metric	Earth	KOI-4777.01	Jupiter
Radius (R⊕)	1.00	0.51	11.21
Mass (M⊕)	1.00	99.20	317.83
Density (g/cm³)	5.51	—	1.33
Surface Gravity (g)	1.00	381.39	2.53
Insolation (S⊕)	1.00	320.00	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	99.200 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 158427808

Gaia DR2

Gaia DR2 2102436351673656704

Gaia DR3

Gaia DR3 2102436351673656704

System

KOI-4777

Percentile among Rocky Terrestrial cohort

Radius 0.510 R⊕ · percentile 1 / cohort 570

Mass 99.200 M⊕ · percentile 99 / cohort 570

Orbital period 0.41 d · percentile 2 / cohort 567

Distance 172.25 pc · percentile 29 / cohort 566

ESI 0.102 · percentile 1 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

0.412 days

Semi-major axis

0.0080 AU

Eccentricity

0.000

Inclination

87.00 °

Year Length

A year here lasts roughly 9.9 hours long on a nearly circular orbit at a mean orbital distance of 0.0080 AU.

Transit Fingerprint

Depth

0.018 %

Duration

0.730 h

Impact parameter b

0.200

Rp / R★

0.011600

Transit midpoint (BJD)

2,454,965.2190

Photometric dip

Transit produces a flux drop of 183 ppm lasting ≈ 0.73 h.

Extended Orbital Architecture

Planet / star radius ratio

0.011600

Semi-major axis / stellar radius

4.280

Impact parameter (b)

0.200

RV semi-amplitude (K)

83.000 m/s

Transit mid-time (BJD)

2,454,965.2190

Long. of periastron (ω)

90.00°

Angular separation (arcsec)

0.04640

Eq. Temperature

1,180K

(907 °C)

Insolation (S⊕)

320.00

Earth = 1.00

Earth Similarity (ESI)

0.102

0 = alien, 1 = Earth-identical

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

Discovery Paper

Primary reference

Ca Ntilde As et al. 2022

Instrument

Kepler CCD Array

Publication

2022-01

Observation locale

Space

Discovery cohort

Planets confirmed in 2022 at Kepler (6 shown).

KOI-7913 b · Sub-Neptune KOI-7368 b · Sub-Neptune Kepler-1972 b · Rocky Terrestrial KOI-984 c · Gas Giant Kepler-1972 c · Rocky Terrestrial KOI-984 b · Neptune-like

Host System: KOI-4777

Spectral Class

M-type red dwarf

Effective Temperature

3,515 K — cooler than the Sun (5,778 K)

Estimated Age

4.00 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.400 R☉

Stellar Mass

0.410 M☉

Metallicity [Fe/H]

0.10

Extended Stellar Properties

Surface gravity (log g)

4.770 dex

Stellar density

8.900 g/cm³

Systemic radial velocity

28.11 km/s

Rotational v·sin i

2.00 km/s

Rotation period

44.00 days

Metallicity ratio

[Fe/H]

Distance

172.25 parsec

Light-years 561.79 ly

V-band magnitude

16.41 mag

Voyager-speed travel 9,907,120 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

5.777 mas

Total Proper Motion

13.852 mas/yr

PM Right Ascension

-2.21 mas/yr

PM Declination

-13.67 mas/yr

Galactic Cartesian (pc)

x = 0.220 · y = -0.709 · z = 0.670

Equatorial (J2000)

RA 287.26215° · Dec 42.03223°

Galactic ℓ, b

72.953° · 14.747°

Ecliptic λ, β

299.823° · 63.695°

HTM-20 index

-2016396463