Key parameters at a glance

A radius of 0.80 Earth radii
A mass of 0.44 Earth masses
Surface gravity around 0.68 g
An orbital period of 6.284 days
Semi-major axis 0.0687 AU
Equilibrium temperature 1,108 K (835 °C)
Distance from Earth 1,608.52 light-years
Earth Similarity Index 0.272
Travel time at Voyager 1 speed 28,366,246 years

Kepler-1581 b Planet Profile

Physical Specs

Radius

0.80 R⊕

Radius (Jupiter)

0.071 R♃

Mass

0.44 M⊕

Mass (Jupiter)

0.001 M♃

Density

4.69 g/cm³

Surface Gravity

0.68 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.272

HZ Position Inner

Controversial No

Discovery

Year 2016

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#479of 570

top 83.9%

This planet

0.80R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Kepler-1365 c 0.80 R⊕ Kepler-1076 b 0.80 R⊕ Kepler-1130 b 0.80 R⊕

Metric	Earth	Kepler-1581 b	Jupiter
Radius (R⊕)	1.00	0.80	11.21
Mass (M⊕)	1.00	0.44	317.83
Density (g/cm³)	5.51	4.69	1.33
Surface Gravity (g)	1.00	0.68	2.53
Insolation (S⊕)	1.00	470.86	0.037

Star Catalogue Identifiers

TIC

TIC 121215710

Gaia DR2

Gaia DR2 2100418850915010432

Gaia DR3

Gaia DR3 2100418850915010432

System

Kepler-1581

Percentile among Rocky Terrestrial cohort

Radius 0.800 R⊕ · percentile 15 / cohort 570

Mass 0.437 M⊕ · percentile 13 / cohort 570

Orbital period 6.28 d · percentile 63 / cohort 567

Distance 493.18 pc · percentile 63 / cohort 566

ESI 0.272 · percentile 31 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

6.284 days

Semi-major axis

0.0687 AU

Eccentricity

0.000

Inclination

89.49 °

Year Length

A year here lasts approximately 6.28 Earth days (1.7% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0687 AU.

Transit Fingerprint

Depth

0.004 %

Duration

4.124 h

Impact parameter b

0.101

Rp / R★

0.005669

Transit midpoint (BJD)

2,454,966.2000

Photometric dip

Transit produces a flux drop of 36 ppm lasting ≈ 4.12 h.

Extended Orbital Architecture

Planet / star radius ratio

0.005669

Semi-major axis / stellar radius

11.490

Impact parameter (b)

0.101

Transit mid-time (BJD)

2,454,966.2000

Angular separation (arcsec)

0.13900

Eq. Temperature

1,108K

(835 °C)

Insolation (S⊕)

470.86

Earth = 1.00

Earth Similarity (ESI)

0.272

0 = alien, 1 = Earth-identical

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

Discovery Paper

Primary reference

Morton et al. 2016

Instrument

Kepler CCD Array

Publication

2016-05

Observation locale

Space

Discovery cohort

Planets confirmed in 2016 at Kepler (12 shown).

Kepler-1512 b · Rocky Terrestrial Kepler-1410 b · Super-Earth Kepler-560 b · Super-Earth Kepler-1389 b · Super-Earth Kepler-1450 b · Super-Earth Kepler-1544 b · Super-Earth Kepler-1459 b · Super-Earth Kepler-1638 b · Super-Earth Kepler-737 b · Super-Earth Kepler-1185 b · Super-Earth Kepler-1178 b · Rocky Terrestrial Kepler-1040 b · Sub-Neptune

Host System: Kepler-1581

Spectral Class

F-type yellow-white

Effective Temperature

6,022 K — hotter than the Sun (5,778 K)

Estimated Age

4.17 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.230 R☉

Stellar Mass

1.120 M☉

Metallicity [Fe/H]

0.07

Extended Stellar Properties

Surface gravity (log g)

4.310 dex

Stellar density

0.430 g/cm³

Systemic radial velocity

-6.34 km/s

Metallicity ratio

[Fe/H]

Distance

493.18 parsec

Light-years 1,608.52 ly

V-band magnitude

12.44 mag

Voyager-speed travel 28,366,246 yr

Multi-band Host Photometry — 17 bands

Astrometric Data

Parallax

1.999 mas

Total Proper Motion

13.560 mas/yr

PM Right Ascension

9.88 mas/yr

PM Declination

9.29 mas/yr

Galactic Cartesian (pc)

x = 0.230 · y = -0.735 · z = 0.637

Equatorial (J2000)

RA 287.37132° · Dec 39.60362°

Galactic ℓ, b

70.694° · 13.694°

Ecliptic λ, β

298.644° · 61.326°

HTM-20 index

-572668957