Key parameters at a glance

A radius of 12.30 Earth radii
A mass of 4,402.56 Earth masses
Surface gravity around 29.10 g
An orbital period of 1,301.360 days
Semi-major axis 2.4460 AU
Distance from Earth 180.97 light-years
Earth Similarity Index 0.339
Travel time at Voyager 1 speed 3,191,347 years

1 sibling around HD 217786

HD 217786 b 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
HD 217786 c	Sub-Neptune	2.61	7.31	2.522	—	2022
HD 217786 b this	Gas Giant	12.30	4,402.56	1,301.360	—	2011

HD 217786 b Planet Profile

Physical Specs

Radius

12.30 R⊕

Radius (Jupiter)

1.100 R♃

Mass

4,402.56 M⊕

Mass (Jupiter)

13.852 M♃

Density

13.00 g/cm³

Surface Gravity

29.10 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.339

HZ Position Unknown

Controversial No

Discovery

Year 2011

Method Radial Velocity

Facility La Silla Observatory

Telescope 3.6 m ESO Telescope

Size rank in cohort

Rank by radius

#1349of 1771

top 76.1%

This planet

12.30R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

HAT-P-13 c 12.30 R⊕ HD 22781 b 12.30 R⊕ CHXR 73 b 12.30 R⊕

Metric	Earth	HD 217786 b	Jupiter
Radius (R⊕)	1.00	12.30	11.21
Mass (M⊕)	1.00	4,402.56	317.83
Density (g/cm³)	5.51	13.00	1.33
Surface Gravity (g)	1.00	29.10	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	4,402.559 M⊕	Direct mass measurement (not derived).
Minimum mass (M sin i)	3,912.468 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 217786

HIP

HIP 113834

TIC

TIC 248048656

Gaia DR2

Gaia DR2 2650902026099857920

Gaia DR3

Gaia DR3 2650902026099857920

System

HD 217786

Percentile among Gas Giant cohort

Radius 12.300 R⊕ · percentile 22 / cohort 1771

Mass 4,402.559 M⊕ · percentile 93 / cohort 1747

Orbital period 1,301.36 d · percentile 81 / cohort 1533

Distance 55.48 pc · percentile 23 / cohort 1759

ESI 0.339 · percentile 68 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

1,301.360 days

Semi-major axis

2.4460 AU

Eccentricity

0.311

Inclination

69.77 °

Year Length

A year here lasts about 3.56 Earth years on a highly eccentric trajectory at a mean orbital distance of 2.4460 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.339

0 = alien, 1 = Earth-identical

Detection Signatures

Radial velocity

Stellar wobble has been measured spectroscopically.

Astrometry

Positional wobble of the host star was measured.

Discovery Paper

Primary reference

Moutou et al. 2011

Instrument

HARPS Spectrograph

Publication

2011-03

Observation locale

Ground

Discovery cohort

Planets confirmed in 2011 at La Silla Observatory (10 shown).

GJ 433 b · Sub-Neptune HD 20794 d · Sub-Neptune HD 192310 b · Neptune-like HD 20794 b · Super-Earth HD 7449 b · Gas Giant HD 192310 c · Neptune-like HIP 5158 c · Gas Giant HD 137388 b · Neptune-like HD 204941 b · Gas Giant HD 7199 b · Unclassified

Host System: HD 217786

Spectral Class

F-type yellow-white

Effective Temperature

5,966 K — hotter than the Sun (5,778 K)

Estimated Age

7.60 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.270 R☉

Stellar Mass

1.140 M☉

Metallicity [Fe/H]

-0.14

Extended Stellar Properties

Surface gravity (log g)

4.350 dex

Stellar density

0.776 g/cm³

Systemic radial velocity

9.98 km/s

Rotational v·sin i

1.40 km/s

Metallicity ratio

[Fe/H]

Distance

55.48 parsec

Light-years 180.97 ly

V-band magnitude

7.78 mag

Voyager-speed travel 3,191,347 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

17.995 mas

Total Proper Motion

191.246 mas/yr

PM Right Ascension

-89.93 mas/yr

PM Declination

-168.78 mas/yr

Galactic Cartesian (pc)

x = 0.969 · y = -0.246 · z = -0.008

Equatorial (J2000)

RA 345.78381° · Dec -0.43036°

Galactic ℓ, b

74.193° · -52.736°

Ecliptic λ, β

346.744° · 5.209°

HTM-20 index

1657565510