Key parameters at a glance

A radius of 13.90 Earth radii
A mass of 257.44 Earth masses
Surface gravity around 1.33 g
An orbital period of 832.970 days
Semi-major axis 1.6620 AU
Distance from Earth 111.52 light-years
Earth Similarity Index 0.292
Travel time at Voyager 1 speed 1,966,740 years

HD 4208 b Planet Profile

Physical Specs

Radius

13.90 R⊕

Radius (Jupiter)

1.240 R♃

Mass

257.44 M⊕

Mass (Jupiter)

0.810 M♃

Density

0.53 g/cm³

Surface Gravity

1.33 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.292

HZ Position Unknown

Controversial No

Discovery

Year 2001

Method Radial Velocity

Facility W. M. Keck Observatory

Telescope 10 m Keck I Telescope

Size rank in cohort

Rank by radius

#456of 1771

top 25.7%

This planet

13.90R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

24 Sex c 13.90 R⊕ HD 148156 b 13.90 R⊕ HD 134987 c 13.90 R⊕

Metric	Earth	HD 4208 b	Jupiter
Radius (R⊕)	1.00	13.90	11.21
Mass (M⊕)	1.00	257.44	317.83
Density (g/cm³)	5.51	0.53	1.33
Surface Gravity (g)	1.00	1.33	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	257.442 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 4208

HIP

HIP 3479

TIC

TIC 43400838

Gaia DR2

Gaia DR2 2343647384368388608

Gaia DR3

Gaia DR3 2343647384368388608

System

HD 4208

Percentile among Gas Giant cohort

Radius 13.900 R⊕ · percentile 72 / cohort 1771

Mass 257.442 M⊕ · percentile 28 / cohort 1747

Orbital period 832.97 d · percentile 74 / cohort 1533

Distance 34.19 pc · percentile 10 / cohort 1759

ESI 0.292 · percentile 56 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

832.970 days

Semi-major axis

1.6620 AU

Eccentricity

0.042

Inclination

— °

Year Length

A year here lasts about 2.28 Earth years on a nearly circular orbit at a mean orbital distance of 1.6620 AU.

Extended Orbital Architecture

RV semi-amplitude (K)

19.030 m/s

Transit mid-time (BJD)

2,452,114.0000

Long. of periastron (ω)

217.63°

Angular separation (arcsec)

48.60000

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.292

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Vogt et al. 2002

Instrument

HIRES Spectrometer

Publication

2002-03

Observation locale

Ground

Discovery cohort

Planets confirmed in 2001 at W. M. Keck Observatory (3 shown).

HD 178911 B b · Gas Giant HD 4203 b · Gas Giant HD 114783 b · Gas Giant

Host System: HD 4208

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,717 K — cooler than the Sun (5,778 K)

Estimated Age

3.81 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.846 R☉

Stellar Mass

0.883 M☉

Metallicity [Fe/H]

-0.28

Extended Stellar Properties

Surface gravity (log g)

4.501 dex

Stellar density

1.734 g/cm³

Systemic radial velocity

56.76 km/s

Rotational v·sin i

0.00 km/s

Rotation period

25.00 days

Activity index (log R'HK)

-4.950

Metallicity ratio

[Fe/H]

Distance

34.19 parsec

Light-years 111.52 ly

V-band magnitude

7.78 mag

Voyager-speed travel 1,966,740 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

29.216 mas

Total Proper Motion

347.307 mas/yr

PM Right Ascension

313.48 mas/yr

PM Declination

149.50 mas/yr

Galactic Cartesian (pc)

x = 0.878 · y = 0.172 · z = -0.446

Equatorial (J2000)

RA 11.11255° · Dec -26.51504°

Galactic ℓ, b

54.008° · -88.325°

Ecliptic λ, β

358.734° · -28.568°

HTM-20 index

372811767

Observation Record

Photometric series

RV measurements

Stellar spectra

Archive notes