Key parameters at a glance

A radius of 13.60 Earth radii
A mass of 435.41 Earth masses
Surface gravity around 2.35 g
An orbital period of 279.800 days
Semi-major axis 0.8960 AU
Distance from Earth 301.72 light-years
Earth Similarity Index 0.335
Travel time at Voyager 1 speed 5,320,879 years

HD 205739 b Planet Profile

Physical Specs

Radius

13.60 R⊕

Radius (Jupiter)

1.210 R♃

Mass

435.41 M⊕

Mass (Jupiter)

1.370 M♃

Density

0.95 g/cm³

Surface Gravity

2.35 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.335

HZ Position Unknown

Controversial No

Discovery

Year 2008

Method Radial Velocity

Facility Las Campanas Observatory

Telescope 6.5 m Magellan II Clay Telescope

Size rank in cohort

Rank by radius

#609of 1771

top 34.3%

This planet

13.60R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

HD 79498 b 13.60 R⊕ HD 19994 b 13.60 R⊕ HIP 14810 c 13.60 R⊕

Metric	Earth	HD 205739 b	Jupiter
Radius (R⊕)	1.00	13.60	11.21
Mass (M⊕)	1.00	435.41	317.83
Density (g/cm³)	5.51	0.95	1.33
Surface Gravity (g)	1.00	2.35	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	435.410 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 205739

HIP

HIP 106824

TIC

TIC 270501383

Gaia DR2

Gaia DR2 6592695123423391616

Gaia DR3

Gaia DR3 6592695123423391616

System

HD 205739

Percentile among Gas Giant cohort

Radius 13.600 R⊕ · percentile 63 / cohort 1771

Mass 435.410 M⊕ · percentile 45 / cohort 1747

Orbital period 279.80 d · percentile 60 / cohort 1533

Distance 92.51 pc · percentile 33 / cohort 1759

ESI 0.335 · percentile 66 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

279.800 days

Semi-major axis

0.8960 AU

Eccentricity

0.270

Inclination

— °

Year Length

A year here lasts approximately 279.80 Earth days (76.6% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.8960 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.335

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Lopez Morales et al. 2008

Instrument

MIKE Spectrograph

Publication

2008-11

Observation locale

Ground

Discovery cohort

Planets confirmed in 2008 at Las Campanas Observatory (3 shown).

HD 154672 b · Gas Giant HD 48265 b · Gas Giant HD 143361 b · Gas Giant

Host System: HD 205739

Spectral Class

F-type yellow-white

Effective Temperature

6,176 K — hotter than the Sun (5,778 K)

Estimated Age

2.84 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.330 R☉

Stellar Mass

1.220 M☉

Metallicity [Fe/H]

0.19

Extended Stellar Properties

Surface gravity (log g)

4.290 dex

Stellar density

0.679 g/cm³

Systemic radial velocity

9.10 km/s

Rotational v·sin i

4.48 km/s

Metallicity ratio

[Fe/H]

Distance

92.51 parsec

Light-years 301.72 ly

V-band magnitude

8.56 mag

Voyager-speed travel 5,320,879 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

10.783 mas

Total Proper Motion

85.039 mas/yr

PM Right Ascension

21.91 mas/yr

PM Declination

-82.17 mas/yr

Galactic Cartesian (pc)

x = 0.693 · y = -0.493 · z = -0.526

Equatorial (J2000)

RA 324.53513° · Dec -31.73784°

Galactic ℓ, b

14.613° · -47.999°

Ecliptic λ, β

316.295° · -16.639°

HTM-20 index

287933595