Key parameters at a glance
- A radius of 18.49 Earth radii
- A mass of 360.10 Earth masses
- Surface gravity around 1.05 g
- An orbital period of 1.364 days
- Semi-major axis 0.0240 AU
- Equilibrium temperature 1,701 K (1428 °C)
- Distance from Earth 576.75 light-years
- Earth Similarity Index 0.059
- Travel time at Voyager 1 speed 10,171,011 years
TOI-1855 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#54of 1771
top 3.0%
This planet
18.49R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | TOI-1855 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 18.49 | 11.21 |
| Mass (M⊕) | 1.00 | 360.10 | 317.83 |
| Density (g/cm³) | 5.51 | 0.31 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.05 | 2.53 |
| Insolation (S⊕) | 1.00 | 852.16 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 360.100 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 81247740
Gaia DR2
Gaia DR2 1247603715050122752
Gaia DR3
Gaia DR3 1247603719345703808
System
TOI-1855
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 1.36 Earth days (0.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0240 AU.
Transit Fingerprint
Depth
0.707 %
Duration
1.194 h
Impact parameter b
1.024
Rp / R★
0.162000
Transit midpoint (BJD)
2,459,243.1974
Photometric dip
Transit produces a flux drop of 7,070 ppm lasting ≈ 1.19 h.
Extended Orbital Architecture
Planet / star radius ratio
0.162000
Semi-major axis / stellar radius
4.950
Impact parameter (b)
1.024
RV semi-amplitude (K)
204.000 m/s
Transit mid-time (BJD)
2,459,243.1974
Long. of periastron (ω)
-100.00°
Angular separation (arcsec)
0.13600
Eq. Temperature
1,701K
(1428 °C)
Insolation (S⊕)
852.16
Earth = 1.00
Earth Similarity (ESI)
0.059
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
Schulte et al. 2024Instrument
TESS CCD Array
Publication
2024-07
Observation locale
Space
Discovery cohort
Planets confirmed in 2024 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: TOI-1855
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,359 K — cooler than the Sun (5,778 K)
Estimated Age
8.20 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
1.041 R☉
Stellar Mass
0.987 M☉
Metallicity [Fe/H]
0.40
Extended Stellar Properties
Surface gravity (log g)
4.397 dex
Stellar density
1.230 g/cm³
Rotational v·sin i
5.74 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
5.626 mas
Total Proper Motion
108.997 mas/yr
PM Right Ascension
-73.22 mas/yr
PM Declination
-80.74 mas/yr
Galactic Cartesian (pc)
x = -0.861 · y = -0.408 · z = 0.304
Equatorial (J2000)
RA 205.35395° · Dec 17.68687°
Galactic ℓ, b
356.212° · 75.099°
Ecliptic λ, β
196.400° · 26.169°
HTM-20 index
1112473139
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