Key parameters at a glance
- A radius of 2.77 Earth radii
- A mass of 8.10 Earth masses
- Surface gravity around 1.06 g
- An orbital period of 17.964 days
- Semi-major axis 0.1330 AU
- Equilibrium temperature 609 K (336 °C)
- Distance from Earth 187.20 light-years
- Earth Similarity Index 0.398
- Travel time at Voyager 1 speed 3,301,355 years
- Almost certainly tidally locked to its host star given the close orbit
TOI-444 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#780of 1978
top 39.4%
This planet
2.77R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | TOI-444 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.77 | 11.21 |
| Mass (M⊕) | 1.00 | 8.10 | 317.83 |
| Density (g/cm³) | 5.51 | 2.09 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.06 | 2.53 |
| Insolation (S⊕) | 1.00 | 23.47 | 0.037 |
Star Catalogue Identifiers
HIP
HIP 19950
TIC
TIC 179034327
Gaia DR2
Gaia DR2 4895489043507741440
Gaia DR3
Gaia DR3 4895489043507741440
System
TOI-444
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 17.96 Earth days (4.9% of a terrestrial year) at a mean orbital distance of 0.1330 AU.
Transit Fingerprint
Depth
0.106 %
Duration
3.761 h
Impact parameter b
0.225
Rp / R★
0.032500
Transit midpoint (BJD)
2,459,190.0391
Photometric dip
Transit produces a flux drop of 1,056 ppm lasting ≈ 3.76 h.
Extended Orbital Architecture
Planet / star radius ratio
0.032500
Semi-major axis / stellar radius
36.768
Impact parameter (b)
0.225
Transit mid-time (BJD)
2,459,190.0391
Angular separation (arcsec)
2.32000
Eq. Temperature
609K
(336 °C)
Insolation (S⊕)
23.47
Earth = 1.00
Earth Similarity (ESI)
0.398
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.
Discovery Paper
Primary reference
Oddo et al. 2023Instrument
TESS CCD Array
Publication
2023-03
Observation locale
Space
Discovery cohort
Planets confirmed in 2023 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: TOI-444
Spectral Class
K-type orange
Effective Temperature
5,225 K — cooler than the Sun (5,778 K)
Estimated Age
0.57 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.779 R☉
Stellar Mass
0.960 M☉
Metallicity [Fe/H]
0.08
Extended Stellar Properties
Surface gravity (log g)
4.640 dex
Stellar density
2.390 g/cm³
Rotation period
13.00 days
Activity index (log R'HK)
-4.460
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
17.394 mas
Total Proper Motion
119.259 mas/yr
PM Right Ascension
-25.83 mas/yr
PM Declination
-116.43 mas/yr
Galactic Cartesian (pc)
x = 0.389 · y = 0.804 · z = -0.450
Equatorial (J2000)
RA 64.18400° · Dec -26.76641°
Galactic ℓ, b
224.793° · -44.581°
Ecliptic λ, β
55.140° · -47.130°
HTM-20 index
836527081
Similar Worlds
Kepler-1140 b
Sub-Neptune · K-type orange
Radius 2.77 R⊕ · 2,141.1 ly
TOI-969 b
Sub-Neptune · K-type orange
Radius 2.77 R⊕ · 252.0 ly
Kepler-1840 b
Sub-Neptune · K-type orange
Radius 2.78 R⊕ · 1,673.5 ly
TOI-1260 c
Sub-Neptune · K-type orange
Radius 2.76 R⊕ · 240.0 ly
Kepler-531 b
Sub-Neptune · K-type orange
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K2-123 b
Sub-Neptune · K-type orange
Radius 2.76 R⊕ · 526.9 ly