Key parameters at a glance

A radius of 19.04 Earth radii
A mass of 286.68 Earth masses
Surface gravity around 0.79 g
An orbital period of 2.990 days
Semi-major axis 0.0432 AU
Equilibrium temperature 1,823 K (1550 °C)
Distance from Earth 711.18 light-years
Earth Similarity Index 0.051
Travel time at Voyager 1 speed 12,541,714 years

KELT-4 A b Planet Profile

Physical Specs

Radius

19.04 R⊕

Radius (Jupiter)

1.699 R♃

Mass

286.68 M⊕

Mass (Jupiter)

0.902 M♃

Density

0.23 g/cm³

Surface Gravity

0.79 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.051

HZ Position Inner

Controversial No

Discovery

Year 2016

Method Transit

Facility KELT

Telescope Mamiya 645 80mm f/1.9

Size rank in cohort

Rank by radius

#44of 1771

top 2.4%

This planet

19.04R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Qatar-7 b 19.06 R⊕ HAT-P-64 b 19.09 R⊕ TOI-615 b 18.98 R⊕

Metric	Earth	KELT-4 A b	Jupiter
Radius (R⊕)	1.00	19.04	11.21
Mass (M⊕)	1.00	286.68	317.83
Density (g/cm³)	5.51	0.23	1.33
Surface Gravity (g)	1.00	0.79	2.53
Insolation (S⊕)	1.00	1,840.00	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	286.683 M⊕	Direct mass measurement (not derived).
Minimum mass (M sin i)	284.776 M⊕	Lower bound from radial-velocity fitting.
Computed mass	286.817 M⊕	Model-computed mass (e.g. from mass-radius relation).

Star Catalogue Identifiers

HIP

HIP 51260

TIC

TIC 165297570

Gaia DR2

Gaia DR2 727624020367528576

Gaia DR3

Gaia DR3 727624020367528576

System

KELT-4

Percentile among Gas Giant cohort

Radius 19.044 R⊕ · percentile 98 / cohort 1771

Mass 286.683 M⊕ · percentile 32 / cohort 1747

Orbital period 2.99 d · percentile 15 / cohort 1533

Distance 218.05 pc · percentile 53 / cohort 1759

ESI 0.051 · percentile 5 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

2.990 days

Semi-major axis

0.0432 AU

Eccentricity

0.000

Inclination

83.16 °

Year Length

A year here lasts approximately 2.99 Earth days (0.8% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0432 AU.

Transit Fingerprint

Depth

1.187 %

Duration

3.463 h

Impact parameter b

0.689

Rp / R★

0.108930

Transit midpoint (BJD)

2,456,190.3020

Photometric dip

Transit produces a flux drop of 11,870 ppm lasting ≈ 3.46 h.

Extended Orbital Architecture

Planet / star radius ratio

0.108930

Semi-major axis / stellar radius

5.792

Impact parameter (b)

0.689

RV semi-amplitude (K)

111.800 m/s

Transit mid-time (BJD)

2,456,190.3020

Sky-projected obliquity (λ)

14.00°

Angular separation (arcsec)

0.19800

Eq. Temperature

1,823K

(1550 °C)

Insolation (S⊕)

1,840.00

Earth = 1.00

Earth Similarity (ESI)

0.051

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

Eastman et al. 2016

Instrument

Apogee 4K CCD Sensor

Publication

2016-02

Observation locale

Ground

Host System: KELT-4 A

Spectral Class

F-type yellow-white

Effective Temperature

6,206 K — hotter than the Sun (5,778 K)

Estimated Age

4.44 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.603 R☉

Stellar Mass

1.201 M☉

Metallicity [Fe/H]

-0.12

Extended Stellar Properties

Surface gravity (log g)

4.108 dex

Stellar density

0.411 g/cm³

Systemic radial velocity

-23.50 km/s

Rotational v·sin i

6.00 km/s

Metallicity ratio

[Fe/H]

Distance

218.05 parsec

Light-years 711.18 ly

V-band magnitude

9.98 mag

Voyager-speed travel 12,541,714 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

4.558 mas

Total Proper Motion

18.644 mas/yr

PM Right Ascension

14.10 mas/yr

PM Declination

-12.20 mas/yr

Galactic Cartesian (pc)

x = -0.831 · y = 0.352 · z = 0.432

Equatorial (J2000)

RA 157.06262° · Dec 25.57314°

Galactic ℓ, b

207.458° · 57.993°

Ecliptic λ, β

149.245° · 14.845°

HTM-20 index

-242168000