Key parameters at a glance

A radius of 3.36 Earth radii
A mass of 64.20 Earth masses
Surface gravity around 5.69 g
An orbital period of 33.006 days
Semi-major axis 0.2178 AU
Equilibrium temperature 778 K (505 °C)
Distance from Earth 3,185.38 light-years
Earth Similarity Index 0.303
Travel time at Voyager 1 speed 56,174,169 years

1 sibling around Kepler-277

Kepler-277 c shares its host star with 1 other confirmed planet. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
Kepler-277 b	Sub-Neptune	2.92	87.30	17.324	964	2013
Kepler-277 c this	Sub-Neptune	3.36	64.20	33.006	778	2013

Kepler-277 c Planet Profile

Physical Specs

Radius

3.36 R⊕

Radius (Jupiter)

0.300 R♃

Mass

64.20 M⊕

Mass (Jupiter)

0.202 M♃

Density

7.80 g/cm³

Surface Gravity

5.69 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.303

HZ Position Inner

Controversial No

Discovery

Year 2013

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#242of 1978

top 12.2%

This planet

3.36R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-1057 b 3.36 R⊕ Kepler-1510 b 3.36 R⊕ Kepler-1083 b 3.36 R⊕

Metric	Earth	Kepler-277 c	Jupiter
Radius (R⊕)	1.00	3.36	11.21
Mass (M⊕)	1.00	64.20	317.83
Density (g/cm³)	5.51	7.80	1.33
Surface Gravity (g)	1.00	5.69	2.53
Insolation (S⊕)	1.00	83.90	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	64.200 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 120961424

Gaia DR2

Gaia DR2 2100389610777053056

Gaia DR3

Gaia DR3 2100389610777053056

System

Kepler-277

Percentile among Sub-Neptune cohort

Radius 3.360 R⊕ · percentile 87 / cohort 1978

Mass 64.200 M⊕ · percentile 98 / cohort 1978

Orbital period 33.01 d · percentile 75 / cohort 1946

Distance 976.64 pc · percentile 77 / cohort 1975

ESI 0.303 · percentile 28 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

33.006 days

Semi-major axis

0.2178 AU

Eccentricity

0.000

Inclination

89.33 °

Year Length

A year here lasts approximately 33.01 Earth days (9.0% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.2178 AU.

Transit Fingerprint

Depth

0.028 %

Duration

7.201 h

Impact parameter b

0.693

Rp / R★

0.016338

Transit midpoint (BJD)

2,454,978.3799

Photometric dip

Transit produces a flux drop of 278 ppm lasting ≈ 7.20 h.

Extended Orbital Architecture

Planet / star radius ratio

0.016338

Semi-major axis / stellar radius

26.150

Impact parameter (b)

0.693

Transit mid-time (BJD)

2,454,978.3799

Angular separation (arcsec)

0.22300

Eq. Temperature

778K

(505 °C)

Insolation (S⊕)

83.90

Earth = 1.00

Earth Similarity (ESI)

0.303

0 = alien, 1 = Earth-identical

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

Detection Signatures

Transit photometry

A transit dip has been observed from at least one telescope.

Transit timing variations

Gravitational interactions from neighbours have been detected.

Discovery Paper

Primary reference

Xie 2014

Instrument

Kepler CCD Array

Publication

2014-02

Observation locale

Space

Discovery cohort

Planets confirmed in 2013 at Kepler (12 shown).

Kepler-69 c · Super-Earth Kepler-61 b · Sub-Neptune Kepler-62 e · Super-Earth KOI-351 f · Sub-Neptune Kepler-62 f · Super-Earth KOI-351 e · Sub-Neptune Kepler-1704 b · Gas Giant Kepler-37 d · Sub-Neptune Kepler-282 e · Sub-Neptune KOI-351 h · Gas Giant KOI-351 d · Sub-Neptune Kepler-114 c · Super-Earth

Host System: Kepler-277

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,946 K — hotter than the Sun (5,778 K)

Estimated Age

3.89 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.690 R☉

Stellar Mass

1.120 M☉

Metallicity [Fe/H]

0.09

Extended Stellar Properties

Surface gravity (log g)

4.030 dex

Stellar density

0.250 g/cm³

Metallicity ratio

[Fe/H]

Distance

976.64 parsec

Light-years 3,185.38 ly

V-band magnitude

13.54 mag

Voyager-speed travel 56,174,169 yr

Multi-band Host Photometry — 17 bands

Astrometric Data

Parallax

0.995 mas

Total Proper Motion

18.245 mas/yr

PM Right Ascension

5.82 mas/yr

PM Declination

17.29 mas/yr

Galactic Cartesian (pc)

x = 0.222 · y = -0.744 · z = 0.630

Equatorial (J2000)

RA 286.58319° · Dec 39.07726°

Galactic ℓ, b

69.944° · 14.038°

Ecliptic λ, β

297.155° · 60.962°

HTM-20 index

-779847540