Key parameters at a glance
- A radius of 1.91 Earth radii
- A mass of 4.29 Earth masses
- Surface gravity around 1.18 g
- An orbital period of 29.650 days
- Semi-major axis 0.1756 AU
- Equilibrium temperature 545 K (272 °C)
- Distance from Earth 66.73 light-years
- Earth Similarity Index 0.506
- Travel time at Voyager 1 speed 1,176,701 years
- Almost certainly tidally locked to its host star given the close orbit
3 siblings around TOI-5789
TOI-5789 d shares its host star with 3 other confirmed planets. Side-by-side measurements below.
| Planet | Type | Radius (R⊕) | Mass (M⊕) | Period (d) | Eq. T (K) | Year |
|---|---|---|---|---|---|---|
| TOI-5789 b | Super-Earth | 1.26 | 2.12 | 2.764 | 1,201 | 2026 |
| TOI-5789 c | Sub-Neptune | 2.86 | 5.00 | 12.928 | 718 | — |
| TOI-5789 d this | Super-Earth | 1.91 | 4.29 | 29.650 | 545 | 2026 |
| TOI-5789 e | Sub-Neptune | 3.43 | 11.61 | 62.980 | 424 | 2026 |
TOI-5789 d Planet Profile
Physical Specs
Classification
Planet Type
Super-Earth
Discovery
Size rank in cohort
Rank by radius
#114of 1176
top 9.6%
This planet
1.91R⊕
Super-Earth median
1.60R⊕
Nearest-size peers
| Metric | Earth | TOI-5789 d | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 1.91 | 11.21 |
| Mass (M⊕) | 1.00 | 4.29 | 317.83 |
| Density (g/cm³) | 5.51 | 3.38 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.18 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Minimum mass (M sin i) | 4.290 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
HD
HD 191785
HIP
HIP 99452
TIC
TIC 87216634
Gaia DR2
Gaia DR2 1809360187271699584
System
TOI-5789
Percentile among Super-Earth cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 29.65 Earth days (8.1% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1756 AU.
Eq. Temperature
545K
(272 °C)
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.506
0 = alien, 1 = Earth-identical
Insufficient insolation data — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.
Discovery Paper
Primary reference
Bonomo et al. 2025Instrument
Multiple Instruments
Publication
2025-10
Observation locale
Ground
Discovery cohort
Planets confirmed in 2026 at Multiple Observatories (12 shown).
Host System: TOI-5789
Spectral Class
K-type orange
Effective Temperature
5,185 K — cooler than the Sun (5,778 K)
Estimated Age
9.40 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.833 R☉
Stellar Mass
0.821 M☉
Metallicity [Fe/H]
-0.12
Extended Stellar Properties
Surface gravity (log g)
4.511 dex
Stellar density
2.000 g/cm³
Systemic radial velocity
-49.32 km/s
Rotational v·sin i
1.20 km/s
Activity index (log R'HK)
-5.153
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 7 bands
Astrometric Data
Parallax
48.852 mas
Total Proper Motion
575.094 mas/yr
PM Right Ascension
-414.66 mas/yr
PM Declination
398.48 mas/yr
Galactic Cartesian (pc)
x = 0.520 · y = -0.807 · z = 0.279
Equatorial (J2000)
RA 302.77345° · Dec 16.18971°
Galactic ℓ, b
56.682° · -9.438°
Ecliptic λ, β
309.527° · 35.240°
HTM-20 index
1705062875
Observation Record
Photometric series
1
Stellar spectra
3
Archive notes
1
Similar Worlds
Kepler-753 b
Super-Earth · K-type orange
Radius 1.91 R⊕ · 896.2 ly
K2-5 b
Super-Earth · K-type orange
Radius 1.91 R⊕ · 661.9 ly
Kepler-1669 c
Super-Earth · K-type orange
Radius 1.90 R⊕ · 1,772.5 ly
K2-339 b
Super-Earth · K-type orange
Radius 1.92 R⊕ · 1,175.3 ly
K2-322 b
Super-Earth · K-type orange
Radius 1.92 R⊕ · 402.5 ly
K2-155 d
Super-Earth · K-type orange
Radius 1.90 R⊕ · 237.4 ly