Key parameters at a glance

A radius of 2.51 Earth radii
A mass of 1.72 Earth masses
Surface gravity around 0.27 g
An orbital period of 25.752 days
Semi-major axis 0.1630 AU
Equilibrium temperature 501 K (228 °C)
Distance from Earth 1,719.89 light-years
Earth Similarity Index 0.378
Travel time at Voyager 1 speed 30,330,242 years

3 siblings around Kepler-176

Kepler-176 d 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-176 b	Super-Earth	1.43	290.54	5.433	841	2014
Kepler-176 c	Sub-Neptune	2.60	1.33	12.760	633	2014
Kepler-176 d this	Sub-Neptune	2.51	1.72	25.752	501	2014
Kepler-176 e	Super-Earth	1.45	0.52	51.166	398	2016

Kepler-176 d Planet Profile

Physical Specs

Radius

2.51 R⊕

Radius (Jupiter)

0.224 R♃

Mass

1.72 M⊕

Mass (Jupiter)

0.005 M♃

Density

0.60 g/cm³

Surface Gravity

0.27 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.378

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

#1159of 1978

top 58.5%

This planet

2.51R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

GJ 876 d 2.51 R⊕ Kepler-239 c 2.51 R⊕ Kepler-445 c 2.51 R⊕

Metric	Earth	Kepler-176 d	Jupiter
Radius (R⊕)	1.00	2.51	11.21
Mass (M⊕)	1.00	1.72	317.83
Density (g/cm³)	5.51	0.60	1.33
Surface Gravity (g)	1.00	0.27	2.53
Insolation (S⊕)	1.00	15.54	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	1.720 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 271159950

Gaia DR2

Gaia DR2 2078286197246582016

Gaia DR3

Gaia DR3 2078286197246582016

System

Kepler-176

Percentile among Sub-Neptune cohort

Radius 2.510 R⊕ · percentile 41 / cohort 1978

Mass 1.720 M⊕ · percentile 0 / cohort 1978

Orbital period 25.75 d · percentile 70 / cohort 1946

Distance 527.32 pc · percentile 49 / cohort 1975

ESI 0.378 · percentile 48 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

25.752 days

Semi-major axis

0.1630 AU

Eccentricity

0.000

Inclination

89.53 °

Year Length

A year here lasts approximately 25.75 Earth days (7.1% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1630 AU.

Transit Fingerprint

Depth

0.074 %

Duration

2.853 h

Impact parameter b

0.660

Rp / R★

0.030267

Transit midpoint (BJD)

2,454,969.4495

Photometric dip

Transit produces a flux drop of 739 ppm lasting ≈ 2.85 h.

Extended Orbital Architecture

Planet / star radius ratio

0.030267

Semi-major axis / stellar radius

34.000

Impact parameter (b)

0.660

Transit mid-time (BJD)

2,454,969.4495

Angular separation (arcsec)

0.30900

Eq. Temperature

501K

(228 °C)

Insolation (S⊕)

15.54

Earth = 1.00

Earth Similarity (ESI)

0.378

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

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-176

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,232 K — cooler than the Sun (5,778 K)

Estimated Age

2.45 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.891 R☉

Stellar Mass

0.860 M☉

Metallicity [Fe/H]

0.13

Extended Stellar Properties

Surface gravity (log g)

4.474 dex

Stellar density

1.740 g/cm³

Metallicity ratio

[Fe/H]

Distance

527.32 parsec

Light-years 1,719.89 ly

V-band magnitude

14.77 mag

Voyager-speed travel 30,330,242 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

1.868 mas

Total Proper Motion

19.900 mas/yr

PM Right Ascension

-15.03 mas/yr

PM Declination

-13.04 mas/yr

Galactic Cartesian (pc)

x = 0.301 · y = -0.655 · z = 0.693

Equatorial (J2000)

RA 294.66790° · Dec 43.85321°

Galactic ℓ, b

77.026° · 10.636°

Ecliptic λ, β

312.740° · 63.677°

HTM-20 index

-1280058698