Key parameters at a glance

A radius of 12.40 Earth radii
A mass of 3,400.76 Earth masses
Surface gravity around 22.12 g
An orbital period of 8,500.000 days
Distance from Earth 416.74 light-years
Earth Similarity Index 0.373
Travel time at Voyager 1 speed 7,349,255 years

1 sibling around HAT-P-2

HAT-P-2 c shares its host star with 1 other confirmed planet. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
HAT-P-2 b	Gas Giant	10.66	2,866.81	5.634	1,540	2007
HAT-P-2 c this	Gas Giant	12.40	3,400.76	8,500.000	—	2023

HAT-P-2 c Planet Profile

Physical Specs

Radius

12.40 R⊕

Radius (Jupiter)

1.110 R♃

Mass

3,400.76 M⊕

Mass (Jupiter)

10.700 M♃

Density

9.80 g/cm³

Surface Gravity

22.12 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.373

HZ Position Unknown

Controversial No

Discovery

Year 2023

Method Radial Velocity

Facility Multiple Observatories

Telescope Multiple Telescopes

Size rank in cohort

Rank by radius

#1298of 1771

top 73.2%

This planet

12.40R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

HD 110014 b 12.40 R⊕ CFBDSIR J145829+101343 b 12.40 R⊕ MOA-2010-BLG-073L b 12.40 R⊕

Metric	Earth	HAT-P-2 c	Jupiter
Radius (R⊕)	1.00	12.40	11.21
Mass (M⊕)	1.00	3,400.76	317.83
Density (g/cm³)	5.51	9.80	1.33
Surface Gravity (g)	1.00	22.12	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	3,400.764 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

HD 147506

HIP

HIP 80076

TIC

TIC 39903405

Gaia DR2

Gaia DR2 1380825667768742144

Gaia DR3

Gaia DR3 1380825667768742144

System

HAT-P-2

Percentile among Gas Giant cohort

Radius 12.400 R⊕ · percentile 25 / cohort 1771

Mass 3,400.764 M⊕ · percentile 89 / cohort 1747

Orbital period 8,500.00 d · percentile 95 / cohort 1533

Distance 127.77 pc · percentile 40 / cohort 1759

ESI 0.373 · percentile 77 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

8,500.000 days

Semi-major axis

— AU

Eccentricity

0.370

Inclination

90.00 °

Year Length

A year here lasts about 23.27 Earth years on a highly eccentric trajectory.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.373

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

De Beurs et al. 2023

Instrument

Multiple Instruments

Publication

2023-10

Observation locale

Ground

Discovery cohort

Planets confirmed in 2023 at Multiple Observatories (12 shown).

AU Mic d · Rocky Terrestrial DMPP-4 b · Sub-Neptune HD 110067 g · Sub-Neptune GJ 806 c · Sub-Neptune HD 110067 f · Sub-Neptune HD 110067 e · Super-Earth TIC 279401253 c · Gas Giant HD 112570 b · Gas Giant HD 110067 d · Sub-Neptune HD 154391 b · Gas Giant HD 110067 b · Sub-Neptune HD 110067 c · Sub-Neptune

Host System: HAT-P-2

Spectral Class

F-type yellow-white

Effective Temperature

6,412 K — hotter than the Sun (5,778 K)

Estimated Age

1.44 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.416 R☉

Stellar Mass

1.330 M☉

Metallicity [Fe/H]

0.12

Extended Stellar Properties

Surface gravity (log g)

4.160 dex

Stellar density

0.434 g/cm³

Systemic radial velocity

-0.22 km/s

Rotational v·sin i

20.80 km/s

Metallicity ratio

[Fe/H]

Distance

127.77 parsec

Light-years 416.74 ly

V-band magnitude

8.72 mag

Voyager-speed travel 7,349,255 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

7.797 mas

Total Proper Motion

30.965 mas/yr

PM Right Ascension

-10.31 mas/yr

PM Declination

-29.20 mas/yr

Galactic Cartesian (pc)

x = -0.317 · y = -0.684 · z = 0.657

Equatorial (J2000)

RA 245.15143° · Dec 41.04796°

Galactic ℓ, b

65.021° · 45.232°

Ecliptic λ, β

229.158° · 61.012°

HTM-20 index

-1362549155

Observation Record

Photometric series

RV measurements

Stellar spectra