Key parameters at a glance

A radius of 19.95 Earth radii
A mass of 301.94 Earth masses
Surface gravity around 0.76 g
An orbital period of 5.032 days
Semi-major axis 0.0671 AU
Equilibrium temperature 1,800 K (1527 °C)
Distance from Earth 1,200.35 light-years
Earth Similarity Index 0.050
Travel time at Voyager 1 speed 21,168,205 years

KELT-12 b Planet Profile

Physical Specs

Radius

19.95 R⊕

Radius (Jupiter)

1.780 R♃

Mass

301.94 M⊕

Mass (Jupiter)

0.950 M♃

Density

0.21 g/cm³

Surface Gravity

0.76 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.050

HZ Position Inner

Controversial No

Discovery

Year 2017

Method Transit

Facility KELT-North

Telescope Mamiya 645 80mm f/1.9

Size rank in cohort

Rank by radius

#31of 1771

top 1.7%

This planet

19.95R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

TOI-2193 A b 19.84 R⊕ GSC 06214-00210 b 20.18 R⊕ TOI-2669 b 19.73 R⊕

Metric	Earth	KELT-12 b	Jupiter
Radius (R⊕)	1.00	19.95	11.21
Mass (M⊕)	1.00	301.94	317.83
Density (g/cm³)	5.51	0.21	1.33
Surface Gravity (g)	1.00	0.76	2.53
Insolation (S⊕)	1.00	1,749.00	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	301.939 M⊕	Direct mass measurement (not derived).
Minimum mass (M sin i)	301.939 M⊕	Lower bound from radial-velocity fitting.
Computed mass	303.350 M⊕	Model-computed mass (e.g. from mass-radius relation).

Star Catalogue Identifiers

TIC

TIC 116242971

Gaia DR2

Gaia DR2 4608935250790855296

Gaia DR3

Gaia DR3 4608935250790855296

System

KELT-12

Percentile among Gas Giant cohort

Radius 19.952 R⊕ · percentile 98 / cohort 1771

Mass 301.939 M⊕ · percentile 33 / cohort 1747

Orbital period 5.03 d · percentile 37 / cohort 1533

Distance 368.03 pc · percentile 67 / cohort 1759

ESI 0.050 · percentile 4 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

5.032 days

Semi-major axis

0.0671 AU

Eccentricity

0.000

Inclination

84.47 °

Year Length

A year here lasts approximately 5.03 Earth days (1.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0671 AU.

Transit Fingerprint

Depth

0.596 %

Duration

5.762 h

Impact parameter b

0.586

Rp / R★

0.077200

Transit midpoint (BJD)

2,457,083.6605

Photometric dip

Transit produces a flux drop of 5,960 ppm lasting ≈ 5.76 h.

Extended Orbital Architecture

Planet / star radius ratio

0.077200

Semi-major axis / stellar radius

6.080

Impact parameter (b)

0.586

RV semi-amplitude (K)

82.000 m/s

Transit mid-time (BJD)

2,457,083.6605

Angular separation (arcsec)

0.18200

Eq. Temperature

1,800K

(1527 °C)

Insolation (S⊕)

1,749.00

Earth = 1.00

Earth Similarity (ESI)

0.050

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

Stevens et al. 2017

Instrument

Apogee 4K CCD Sensor

Publication

2017-04

Observation locale

Ground

Discovery cohort

Planets confirmed in 2017 at KELT-North (3 shown).

KELT-18 b · Gas Giant KELT-20 b · Gas Giant KELT-9 b · Gas Giant

Host System: KELT-12

Spectral Class

F-type yellow-white

Effective Temperature

6,279 K — hotter than the Sun (5,778 K)

Estimated Age

2.20 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

2.370 R☉

Stellar Mass

1.591 M☉

Metallicity [Fe/H]

0.19

Extended Stellar Properties

Surface gravity (log g)

3.889 dex

Stellar density

0.168 g/cm³

Systemic radial velocity

-23.60 km/s

Metallicity ratio

[Fe/H]

Distance

368.03 parsec

Light-years 1,200.35 ly

V-band magnitude

10.59 mag

Voyager-speed travel 21,168,205 yr

Multi-band Host Photometry — 14 bands

Astrometric Data

Parallax

2.688 mas

Total Proper Motion

10.963 mas/yr

PM Right Ascension

-0.14 mas/yr

PM Declination

-10.96 mas/yr

Galactic Cartesian (pc)

x = -0.033 · y = -0.802 · z = 0.596

Equatorial (J2000)

RA 267.64049° · Dec 36.57018°

Galactic ℓ, b

62.189° · 27.343°

Ecliptic λ, β

266.207° · 59.978°

HTM-20 index

-197071551