Key parameters at a glance

A radius of 3.87 Earth radii
A mass of 14.31 Earth masses
Surface gravity around 0.96 g
An orbital period of 95.945 days
Semi-major axis 0.3809 AU
Distance from Earth 114.33 light-years
Earth Similarity Index 0.555
Travel time at Voyager 1 speed 2,016,297 years

1 sibling around HD 51608

HD 51608 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
HD 51608 b	Sub-Neptune	3.62	12.77	14.073	—	2019
HD 51608 c this	Sub-Neptune	3.87	14.31	95.945	—	2019

HD 51608 c Planet Profile

Physical Specs

Radius

3.87 R⊕

Radius (Jupiter)

0.346 R♃

Mass

14.31 M⊕

Mass (Jupiter)

0.045 M♃

Density

1.36 g/cm³

Surface Gravity

0.96 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.555

HZ Position Unknown

Controversial No

Discovery

Year 2019

Method Radial Velocity

Facility La Silla Observatory

Telescope 3.6 m ESO Telescope

Size rank in cohort

Rank by radius

#38of 1978

top 1.9%

This planet

3.87R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-254 b 3.87 R⊕ Kepler-1661 b 3.87 R⊕ G 192-15 c 3.87 R⊕

Metric	Earth	HD 51608 c	Jupiter
Radius (R⊕)	1.00	3.87	11.21
Mass (M⊕)	1.00	14.31	317.83
Density (g/cm³)	5.51	1.36	1.33
Surface Gravity (g)	1.00	0.96	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	14.310 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 51608

HIP

HIP 33229

TIC

TIC 279246287

Gaia DR2

Gaia DR2 5485320853638354304

Gaia DR3

Gaia DR3 5485320853638354304

System

HD 51608

Percentile among Sub-Neptune cohort

Radius 3.870 R⊕ · percentile 98 / cohort 1978

Mass 14.310 M⊕ · percentile 91 / cohort 1978

Orbital period 95.94 d · percentile 94 / cohort 1946

Distance 35.06 pc · percentile 9 / cohort 1975

ESI 0.555 · percentile 77 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

95.945 days

Semi-major axis

0.3809 AU

Eccentricity

0.140

Inclination

— °

Year Length

A year here lasts approximately 95.94 Earth days (26.3% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.3809 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.555

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Udry et al. 2019

Instrument

HARPS Spectrograph

Publication

2019-02

Observation locale

Ground

Discovery cohort

Planets confirmed in 2019 at La Silla Observatory (12 shown).

HD 20781 b · Rocky Terrestrial HD 20781 c · Sub-Neptune HD 21693 b · Sub-Neptune HD 45184 c · Sub-Neptune HD 134060 b · Sub-Neptune HD 31527 b · Sub-Neptune HD 20781 d · Sub-Neptune HD 20003 b · Sub-Neptune HD 31527 d · Sub-Neptune HD 45184 b · Sub-Neptune HD 51608 b · Sub-Neptune HD 136352 d · Sub-Neptune

Host System: HD 51608

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,358 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.916 R☉

Stellar Mass

0.800 M☉

Metallicity [Fe/H]

-0.07

Extended Stellar Properties

Surface gravity (log g)

4.360 dex

Stellar density

1.698 g/cm³

Systemic radial velocity

39.10 km/s

Rotational v·sin i

1.30 km/s

Rotation period

40.00 days

Activity index (log R'HK)

-4.970

Metallicity ratio

[Fe/H]

Distance

35.06 parsec

Light-years 114.33 ly

V-band magnitude

8.17 mag

Voyager-speed travel 2,016,297 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

28.497 mas

Total Proper Motion

162.853 mas/yr

PM Right Ascension

-27.95 mas/yr

PM Declination

-160.44 mas/yr

Galactic Cartesian (pc)

x = -0.135 · y = 0.554 · z = -0.822

Equatorial (J2000)

RA 103.71371° · Dec -55.26002°

Galactic ℓ, b

265.156° · -21.539°

Ecliptic λ, β

126.725° · -76.944°

HTM-20 index

2029824335