Key parameters at a glance

A radius of 18.06 Earth radii
A mass of 176.08 Earth masses
Surface gravity around 0.54 g
An orbital period of 2.605 days
Semi-major axis 0.0404 AU
Equilibrium temperature 1,818 K (1545 °C)
Distance from Earth 2,408.72 light-years
Earth Similarity Index 0.049
Travel time at Voyager 1 speed 42,477,846 years

HAT-P-65 b Planet Profile

Physical Specs

Radius

18.06 R⊕

Radius (Jupiter)

1.611 R♃

Mass

176.08 M⊕

Mass (Jupiter)

0.554 M♃

Density

0.16 g/cm³

Surface Gravity

0.54 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.049

HZ Position Inner

Controversial No

Discovery

Year 2016

Method Transit

Facility HATNet

Telescope Canon 200mm f/1.8L

Size rank in cohort

Rank by radius

#69of 1771

top 3.8%

This planet

18.06R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

TrES-4 b 18.05 R⊕ NGTS-31 b 18.05 R⊕ OGLE2-TR-L9 b 18.05 R⊕

Metric	Earth	HAT-P-65 b	Jupiter
Radius (R⊕)	1.00	18.06	11.21
Mass (M⊕)	1.00	176.08	317.83
Density (g/cm³)	5.51	0.16	1.33
Surface Gravity (g)	1.00	0.54	2.53
Insolation (S⊕)	1.00	1,821.00	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	176.077 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 283419843

Gaia DR2

Gaia DR2 1757302881526250496

Gaia DR3

Gaia DR3 1757302881526250496

System

HAT-P-65

Percentile among Gas Giant cohort

Radius 18.058 R⊕ · percentile 96 / cohort 1771

Mass 176.077 M⊕ · percentile 16 / cohort 1747

Orbital period 2.61 d · percentile 11 / cohort 1533

Distance 738.52 pc · percentile 82 / cohort 1759

ESI 0.049 · percentile 4 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

2.605 days

Semi-major axis

0.0404 AU

Eccentricity

0.304

Inclination

88.30 °

Year Length

A year here lasts approximately 2.61 Earth days (0.7% of a terrestrial year) on a highly eccentric trajectory at a mean orbital distance of 0.0404 AU.

Transit Fingerprint

Depth

1.114 %

Duration

4.366 h

Impact parameter b

0.464

Rp / R★

0.100600

Transit midpoint (BJD)

2,458,139.3507

Photometric dip

Transit produces a flux drop of 11,140 ppm lasting ≈ 4.37 h.

Extended Orbital Architecture

Planet / star radius ratio

0.100600

Semi-major axis / stellar radius

5.180

Impact parameter (b)

0.464

RV semi-amplitude (K)

68.000 m/s

Transit mid-time (BJD)

2,458,139.3507

Angular separation (arcsec)

0.05470

Eq. Temperature

1,818K

(1545 °C)

Insolation (S⊕)

1,821.00

Earth = 1.00

Earth Similarity (ESI)

0.049

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

Hartman et al. 2016

Instrument

2K CCD Sensor

Publication

2016-12

Observation locale

Ground

Host System: HAT-P-65

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,872 K — hotter than the Sun (5,778 K)

Estimated Age

3.90 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.666 R☉

Stellar Mass

1.297 M☉

Metallicity [Fe/H]

0.21

Extended Stellar Properties

Surface gravity (log g)

4.108 dex

Stellar density

0.397 g/cm³

Rotational v·sin i

7.10 km/s

Metallicity ratio

[Fe/H]

Distance

738.52 parsec

Light-years 2,408.72 ly

V-band magnitude

13.12 mag

Voyager-speed travel 42,477,846 yr

Multi-band Host Photometry — 15 bands

Astrometric Data

Parallax

1.326 mas

Total Proper Motion

7.461 mas/yr

PM Right Ascension

4.22 mas/yr

PM Declination

-6.15 mas/yr

Galactic Cartesian (pc)

x = 0.703 · y = -0.681 · z = 0.208

Equatorial (J2000)

RA 315.90549° · Dec 11.98937°

Galactic ℓ, b

60.502° · -22.335°

Ecliptic λ, β

322.353° · 27.474°

HTM-20 index

1296876335