Key parameters at a glance

A radius of 3.52 Earth radii
A mass of 12.19 Earth masses
Surface gravity around 0.98 g
An orbital period of 5.885 days
Semi-major axis 0.0644 AU
Distance from Earth 71.60 light-years
Earth Similarity Index 0.586
Travel time at Voyager 1 speed 1,262,696 years

1 sibling around HD 45184

HD 45184 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 45184 b this	Sub-Neptune	3.52	12.19	5.885	—	2019
HD 45184 c	Sub-Neptune	2.91	8.81	13.135	—	2019

HD 45184 b Planet Profile

Physical Specs

Radius

3.52 R⊕

Radius (Jupiter)

0.314 R♃

Mass

12.19 M⊕

Mass (Jupiter)

0.038 M♃

Density

1.54 g/cm³

Surface Gravity

0.98 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.586

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

#169of 1978

top 8.5%

This planet

3.52R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

K2-283 b 3.52 R⊕ Kepler-687 b 3.52 R⊕ Kepler-657 b 3.52 R⊕

Metric	Earth	HD 45184 b	Jupiter
Radius (R⊕)	1.00	3.52	11.21
Mass (M⊕)	1.00	12.19	317.83
Density (g/cm³)	5.51	1.54	1.33
Surface Gravity (g)	1.00	0.98	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	12.190 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 45184

HIP

HIP 30503

TIC

TIC 49831913

Gaia DR2

Gaia DR2 2898239468873596800

Gaia DR3

Gaia DR3 2898239468873596800

System

HD 45184

Percentile among Sub-Neptune cohort

Radius 3.520 R⊕ · percentile 91 / cohort 1978

Mass 12.190 M⊕ · percentile 84 / cohort 1978

Orbital period 5.89 d · percentile 17 / cohort 1946

Distance 21.95 pc · percentile 5 / cohort 1975

ESI 0.586 · percentile 81 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

5.885 days

Semi-major axis

0.0644 AU

Eccentricity

0.070

Inclination

— °

Year Length

A year here lasts approximately 5.89 Earth days (1.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0644 AU.

Extended Orbital Architecture

RV semi-amplitude (K)

4.260 m/s

Transit mid-time (BJD)

2,455,946.5300

Long. of periastron (ω)

145.80°

Angular separation (arcsec)

2.93000

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.586

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 51608 b · Sub-Neptune HD 136352 d · Sub-Neptune HD 20781 e · Sub-Neptune

Host System: HD 45184

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,869 K — hotter than the Sun (5,778 K)

Estimated Age

6.80 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.075 R☉

Stellar Mass

1.030 M☉

Metallicity [Fe/H]

0.04

Extended Stellar Properties

Surface gravity (log g)

4.470 dex

Stellar density

1.282 g/cm³

Systemic radial velocity

-4.10 km/s

Rotational v·sin i

2.10 km/s

Rotation period

21.50 days

Activity index (log R'HK)

-4.950

Metallicity ratio

[Fe/H]

Distance

21.95 parsec

Light-years 71.60 ly

V-band magnitude

6.38 mag

Voyager-speed travel 1,262,696 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

45.522 mas

Total Proper Motion

205.308 mas/yr

PM Right Ascension

-165.26 mas/yr

PM Declination

-121.83 mas/yr

Galactic Cartesian (pc)

x = -0.094 · y = 0.871 · z = -0.481

Equatorial (J2000)

RA 96.18202° · Dec -28.78064°

Galactic ℓ, b

236.626° · -18.074°

Ecliptic λ, β

98.821° · -52.031°

HTM-20 index

219781290