Key parameters at a glance

A radius of 14.83 Earth radii
A mass of 298.12 Earth masses
Surface gravity around 1.36 g
An orbital period of 2.255 days
Semi-major axis 0.0330 AU
Equilibrium temperature 1,561 K (1288 °C)
Distance from Earth 411.81 light-years
Earth Similarity Index 0.076
Travel time at Voyager 1 speed 7,262,231 years

KELT-23 A b Planet Profile

Physical Specs

Radius

14.83 R⊕

Radius (Jupiter)

1.323 R♃

Mass

298.12 M⊕

Mass (Jupiter)

0.938 M♃

Density

0.50 g/cm³

Surface Gravity

1.36 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.076

HZ Position Inner

Controversial No

Discovery

Year 2019

Method Transit

Facility KELT-North

Telescope Mamiya 645 80mm f/1.9

Size rank in cohort

Rank by radius

#249of 1771

top 14.0%

This planet

14.83R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

HAT-P-55 b 14.84 R⊕ WASP-188 b 14.82 R⊕ Gaia-2 b 14.82 R⊕

Metric	Earth	KELT-23 A b	Jupiter
Radius (R⊕)	1.00	14.83	11.21
Mass (M⊕)	1.00	298.12	317.83
Density (g/cm³)	5.51	0.50	1.33
Surface Gravity (g)	1.00	1.36	2.53
Insolation (S⊕)	1.00	991.18	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	298.125 M⊕	Direct mass measurement (not derived).
Minimum mass (M sin i)	297.171 M⊕	Lower bound from radial-velocity fitting.
Computed mass	298.144 M⊕	Model-computed mass (e.g. from mass-radius relation).

Star Catalogue Identifiers

TIC

TIC 458478250

Gaia DR2

Gaia DR2 1644692064543192704

Gaia DR3

Gaia DR3 1644692064543192704

System

KELT-23

Percentile among Gas Giant cohort

Radius 14.830 R⊕ · percentile 86 / cohort 1771

Mass 298.125 M⊕ · percentile 33 / cohort 1747

Orbital period 2.26 d · percentile 9 / cohort 1533

Distance 126.26 pc · percentile 40 / cohort 1759

ESI 0.076 · percentile 16 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

2.255 days

Semi-major axis

0.0330 AU

Eccentricity

0.000

Inclination

85.37 °

Year Length

A year here lasts approximately 2.26 Earth days (0.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0330 AU.

Transit Fingerprint

Depth

1.864 %

Duration

2.381 h

Impact parameter b

0.576

Rp / R★

0.136500

Transit midpoint (BJD)

2,458,140.3792

Photometric dip

Transit produces a flux drop of 18,640 ppm lasting ≈ 2.38 h.

Extended Orbital Architecture

Planet / star radius ratio

0.136500

Semi-major axis / stellar radius

7.130

Impact parameter (b)

0.576

RV semi-amplitude (K)

150.600 m/s

Transit mid-time (BJD)

2,458,140.3792

Sky-projected obliquity (λ)

180.40°

Angular separation (arcsec)

0.26200

Eq. Temperature

1,561K

(1288 °C)

Insolation (S⊕)

991.18

Earth = 1.00

Earth Similarity (ESI)

0.076

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

Johns et al. 2019

Instrument

Apogee 4K CCD Sensor

Publication

2019-08

Observation locale

Ground

Host System: KELT-23 A

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,899 K — hotter than the Sun (5,778 K)

Estimated Age

6.40 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.996 R☉

Stellar Mass

0.944 M☉

Metallicity [Fe/H]

-0.11

Extended Stellar Properties

Surface gravity (log g)

4.417 dex

Stellar density

1.349 g/cm³

Systemic radial velocity

-15.22 km/s

Rotational v·sin i

2.42 km/s

Metallicity ratio

[Fe/H]

Distance

126.26 parsec

Light-years 411.81 ly

V-band magnitude

10.31 mag

Voyager-speed travel 7,262,231 yr

Multi-band Host Photometry — 14 bands

Astrometric Data

Parallax

7.891 mas

Total Proper Motion

12.225 mas/yr

PM Right Ascension

0.43 mas/yr

PM Declination

-12.22 mas/yr

Galactic Cartesian (pc)

x = -0.246 · y = -0.317 · z = 0.916

Equatorial (J2000)

RA 232.14664° · Dec 66.35871°

Galactic ℓ, b

102.282° · 43.943°

Ecliptic λ, β

163.282° · 75.112°

HTM-20 index

1362238447