Key parameters at a glance

A radius of 2.67 Earth radii
A mass of 7.63 Earth masses
Surface gravity around 1.07 g
An orbital period of 1.876 days
Semi-major axis 0.0300 AU
Distance from Earth 89.89 light-years
Earth Similarity Index 0.681
Travel time at Voyager 1 speed 1,585,243 years

1 sibling around HD 155918

HD 155918 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 155918 b this	Sub-Neptune	2.67	7.63	1.876	—	2022
HD 155918 c	Gas Giant	12.80	1,878.05	17,202.194	—	2022

HD 155918 b Planet Profile

Physical Specs

Radius

2.67 R⊕

Radius (Jupiter)

0.239 R♃

Mass

7.63 M⊕

Mass (Jupiter)

0.024 M♃

Density

2.20 g/cm³

Surface Gravity

1.07 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.681

HZ Position Unknown

Controversial No

Discovery

Year 2022

Method Radial Velocity

Facility Multiple Observatories

Telescope Multiple Telescopes

Size rank in cohort

Rank by radius

#904of 1978

top 45.7%

This planet

2.67R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-357 c 2.67 R⊕ Kepler-96 b 2.67 R⊕ K2-26 b 2.67 R⊕

Metric	Earth	HD 155918 b	Jupiter
Radius (R⊕)	1.00	2.67	11.21
Mass (M⊕)	1.00	7.63	317.83
Density (g/cm³)	5.51	2.20	1.33
Surface Gravity (g)	1.00	1.07	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	7.628 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 155918

HIP

HIP 84988

TIC

TIC 311649327

Gaia DR2

Gaia DR2 5801950515627094400

Gaia DR3

Gaia DR3 5801950515627094400

System

HIP 84988

Percentile among Sub-Neptune cohort

Radius 2.670 R⊕ · percentile 53 / cohort 1978

Mass 7.628 M⊕ · percentile 50 / cohort 1978

Orbital period 1.88 d · percentile 2 / cohort 1946

Distance 27.56 pc · percentile 7 / cohort 1975

ESI 0.681 · percentile 91 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

1.876 days

Semi-major axis

0.0300 AU

Eccentricity

0.194

Inclination

— °

Year Length

A year here lasts approximately 1.88 Earth days (0.5% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0300 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.681

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Feng et al. 2022

Instrument

Multiple Instruments

Publication

2022-09

Observation locale

Ground

Discovery cohort

Planets confirmed in 2022 at Multiple Observatories (12 shown).

Kepler-138 e · Rocky Terrestrial HD 93351 b · Super-Earth GJ 1002 b · Rocky Terrestrial GJ 2030 b · Sub-Neptune GJ 3929 c · Sub-Neptune HD 217786 c · Sub-Neptune GJ 1002 c · Rocky Terrestrial HD 213519 b · Sub-Neptune HD 191939 g · Sub-Neptune GJ 514 b · Sub-Neptune HD 12235 b · Sub-Neptune HD 18143 b · Sub-Neptune

Host System: HD 155918

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,772 K — cooler than the Sun (5,778 K)

Estimated Age

12.30 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.019 R☉

Stellar Mass

1.030 M☉

Metallicity [Fe/H]

-0.66

Extended Stellar Properties

Surface gravity (log g)

4.435 dex

Stellar density

1.372 g/cm³

Systemic radial velocity

59.70 km/s

Rotational v·sin i

0.00 km/s

Metallicity ratio

[M/H]

Distance

27.56 parsec

Light-years 89.89 ly

V-band magnitude

7.00 mag

Voyager-speed travel 1,585,243 yr

Multi-band Host Photometry — 8 bands

Astrometric Data

Parallax

36.254 mas

Total Proper Motion

990.621 mas/yr

PM Right Ascension

-957.86 mas/yr

PM Declination

-252.66 mas/yr

Galactic Cartesian (pc)

x = -0.042 · y = -0.249 · z = -0.967

Equatorial (J2000)

RA 260.53640° · Dec -75.34924°

Galactic ℓ, b

317.430° · -20.834°

Ecliptic λ, β

266.120° · -52.037°

HTM-20 index

1407590339