Key parameters at a glance

A radius of 0.82 Earth radii
A mass of 5.00 Earth masses
Surface gravity around 7.44 g
An orbital period of 2.465 days
Semi-major axis 0.0359 AU
Equilibrium temperature 1,561 K (1288 °C)
Distance from Earth 289.57 light-years
Earth Similarity Index 0.099
Travel time at Voyager 1 speed 5,106,597 years

Kepler-408 b Planet Profile

Physical Specs

Radius

0.82 R⊕

Radius (Jupiter)

0.073 R♃

Mass

5.00 M⊕

Mass (Jupiter)

0.016 M♃

Density

— g/cm³

Surface Gravity

7.44 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.099

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

#465of 570

top 81.4%

This planet

0.82R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Kepler-32 f 0.82 R⊕ Kepler-106 b 0.82 R⊕ Kepler-390 b 0.82 R⊕

Metric	Earth	Kepler-408 b	Jupiter
Radius (R⊕)	1.00	0.82	11.21
Mass (M⊕)	1.00	5.00	317.83
Density (g/cm³)	5.51	—	1.33
Surface Gravity (g)	1.00	7.44	2.53
Insolation (S⊕)	1.00	1,503.58	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	5.000 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 48450369

Gaia DR2

Gaia DR2 2131593785132997632

Gaia DR3

Gaia DR3 2131593785132997632

System

Kepler-408

Percentile among Rocky Terrestrial cohort

Radius 0.820 R⊕ · percentile 17 / cohort 570

Mass 5.000 M⊕ · percentile 95 / cohort 570

Orbital period 2.47 d · percentile 29 / cohort 567

Distance 88.78 pc · percentile 22 / cohort 566

ESI 0.099 · percentile 1 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

2.465 days

Semi-major axis

0.0359 AU

Eccentricity

0.000

Inclination

87.51 °

Year Length

A year here lasts approximately 2.47 Earth days (0.7% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0359 AU.

Transit Fingerprint

Depth

0.003 %

Duration

1.231 h

Impact parameter b

0.920

Rp / R★

0.006136

Transit midpoint (BJD)

2,454,965.6793

Photometric dip

Transit produces a flux drop of 31 ppm lasting ≈ 1.23 h.

Extended Orbital Architecture

Planet / star radius ratio

0.006136

Semi-major axis / stellar radius

5.900

Impact parameter (b)

0.920

Transit mid-time (BJD)

2,454,965.6793

Angular separation (arcsec)

0.40500

Eq. Temperature

1,561K

(1288 °C)

Insolation (S⊕)

1,503.58

Earth = 1.00

Earth Similarity (ESI)

0.099

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.

Detection Signatures

Transit photometry

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

Radial velocity

Stellar wobble has been measured spectroscopically.

Discovery Paper

Primary reference

Marcy et al. 2014

Instrument

Kepler CCD Array

Publication

2014-02

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-408

Spectral Class

F-type yellow-white

Effective Temperature

6,104 K — hotter than the Sun (5,778 K)

Estimated Age

6.68 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.230 R☉

Stellar Mass

1.080 M☉

Metallicity [Fe/H]

-0.20

Extended Stellar Properties

Surface gravity (log g)

4.294 dex

Stellar density

0.820 g/cm³

Systemic radial velocity

-54.92 km/s

Rotational v·sin i

3.10 km/s

Metallicity ratio

[Fe/H]

Distance

88.78 parsec

Light-years 289.57 ly

V-band magnitude

8.83 mag

Voyager-speed travel 5,106,597 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

11.235 mas

Total Proper Motion

10.424 mas/yr

PM Right Ascension

4.58 mas/yr

PM Declination

9.36 mas/yr

Galactic Cartesian (pc)

x = 0.169 · y = -0.642 · z = 0.748

Equatorial (J2000)

RA 284.78622° · Dec 48.42326°

Galactic ℓ, b

78.475° · 18.738°

Ecliptic λ, β

300.184° · 70.317°

HTM-20 index

-135058448