Key parameters at a glance
- A radius of 7.40 Earth radii
- A mass of 34.96 Earth masses
- Surface gravity around 0.64 g
- An orbital period of 11.814 days
- Semi-major axis 0.1066 AU
- Equilibrium temperature 1,089 K (816 °C)
- Distance from Earth 431.65 light-years
- Earth Similarity Index 0.136
- Travel time at Voyager 1 speed 7,612,168 years
HD 89345 b Planet Profile
Physical Specs
Classification
Planet Type
Neptune-like
Discovery
Size rank in cohort
Rank by radius
#181of 574
top 31.4%
This planet
7.40R⊕
Neptune-like median
6.39R⊕
Nearest-size peers
| Metric | Earth | HD 89345 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 7.40 | 11.21 |
| Mass (M⊕) | 1.00 | 34.96 | 317.83 |
| Density (g/cm³) | 5.51 | 0.47 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.64 | 2.53 |
| Insolation (S⊕) | 1.00 | 275.64 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 34.961 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 34.961 M⊕ | Lower bound from radial-velocity fitting. |
| Computed mass | 35.003 M⊕ | Model-computed mass (e.g. from mass-radius relation). |
Star Catalogue Identifiers
HD
HD 89345
HIP
HIP 50496
TIC
TIC 350020859
Gaia DR2
Gaia DR2 3877070590167177344
Gaia DR3
Gaia DR3 3877070590167177344
System
HD 89345
Percentile among Neptune-like cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 11.81 Earth days (3.2% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.1066 AU.
Transit Fingerprint
Depth
0.151 %
Duration
5.734 h
Impact parameter b
0.645
Rp / R★
0.038900
Transit midpoint (BJD)
2,457,913.8052
Photometric dip
Transit produces a flux drop of 1,509 ppm lasting ≈ 5.73 h.
Extended Orbital Architecture
Planet / star radius ratio
0.038900
Semi-major axis / stellar radius
13.110
Impact parameter (b)
0.645
RV semi-amplitude (K)
9.200 m/s
Transit mid-time (BJD)
2,457,913.8052
Long. of periastron (ω)
-13.00°
Sky-projected obliquity (λ)
74.20°
True obliquity (ψ)
80.10°
Angular separation (arcsec)
0.80500
Eq. Temperature
1,089K
(816 °C)
Insolation (S⊕)
275.64
Earth = 1.00
Earth Similarity (ESI)
0.136
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.
Detection Signatures
Transit photometry
A transit dip has been observed from at least one telescope.
Radial velocity
Stellar wobble has been measured spectroscopically.
Discovery Paper
Primary reference
Van Eylen et al. 2018Instrument
Kepler CCD Array
Publication
2018-08
Observation locale
Space
Discovery cohort
Planets confirmed in 2018 at K2 (12 shown).
Host System: HD 89345
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,576 K — cooler than the Sun (5,778 K)
Estimated Age
7.53 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
1.747 R☉
Stellar Mass
1.157 M☉
Metallicity [Fe/H]
0.42
Extended Stellar Properties
Surface gravity (log g)
4.016 dex
Stellar density
0.305 g/cm³
Systemic radial velocity
2.35 km/s
Rotational v·sin i
0.58 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 12 bands
Astrometric Data
Parallax
7.527 mas
Total Proper Motion
42.784 mas/yr
PM Right Ascension
5.35 mas/yr
PM Declination
-42.45 mas/yr
Galactic Cartesian (pc)
x = -0.890 · y = 0.421 · z = 0.176
Equatorial (J2000)
RA 154.67110° · Dec 10.12885°
Galactic ℓ, b
230.808° · 50.247°
Ecliptic λ, β
152.844° · -0.354°
HTM-20 index
964503568
Similar Worlds
Kepler-682 b
Neptune-like · G-type yellow (Sun-like)
Radius 7.37 R⊕ · 6,455.4 ly
HD 199509 b
Neptune-like · G-type yellow (Sun-like)
Radius 7.43 R⊕ · 79.3 ly
TOI-1203 e
Neptune-like · G-type yellow (Sun-like)
Radius 7.31 R⊕ · 212.0 ly
TOI-7510 b
Neptune-like · G-type yellow (Sun-like)
Radius 7.31 R⊕ · 812.1 ly
K2-24 c
Neptune-like · G-type yellow (Sun-like)
Radius 7.50 R⊕ · 556.3 ly
K2-280 b
Neptune-like · G-type yellow (Sun-like)
Radius 7.50 R⊕ · 1,277.0 ly