Key parameters at a glance
- A radius of 0.99 Earth radii
- A mass of 0.94 Earth masses
- Surface gravity around 0.96 g
- An orbital period of 2.029 days
- Semi-major axis 0.0204 AU
- Equilibrium temperature 586 K (313 °C)
- Distance from Earth 40.71 light-years
- Earth Similarity Index 0.555
- Travel time at Voyager 1 speed 717,900 years
- Almost certainly tidally locked to its host star given the close orbit
Context from the literature
LHS 475 b is a terrestrial planet orbiting the star LHS 475 which is about 40.7 light years away, in the constellation of Octans. It was the first extrasolar planet to be confirmed by the James Webb Space Telescope. It completes an orbit every 2 days and is 99% the diameter of Earth. It is also one of the most similar-to-Earth exoplanets discovered, in terms of radius.
Excerpted from Wikipedia · full article
LHS 475 b Planet Profile
Physical Specs
Classification
Planet Type
Rocky Terrestrial
Discovery
Size rank in cohort
Rank by radius
#345of 570
top 60.4%
This planet
0.99R⊕
Rocky Terrestrial median
1.01R⊕
Nearest-size peers
| Metric | Earth | LHS 475 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 0.99 | 11.21 |
| Mass (M⊕) | 1.00 | 0.94 | 317.83 |
| Density (g/cm³) | 5.51 | 5.31 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.96 | 2.53 |
| Insolation (S⊕) | 1.00 | 20.80 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 369327947
Gaia DR2
Gaia DR2 6347643496607835520
Gaia DR3
Gaia DR3 6347643496607835520
System
LHS 475
Percentile among Rocky Terrestrial cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 2.03 Earth days (0.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0204 AU.
Transit Fingerprint
Depth
0.110 %
Duration
0.725 h
Impact parameter b
0.701
Rp / R★
0.032570
Transit midpoint (BJD)
2,459,822.3763
Photometric dip
Transit produces a flux drop of 1,101 ppm lasting ≈ 0.73 h.
Extended Orbital Architecture
Planet / star radius ratio
0.032570
Semi-major axis / stellar radius
15.872
Impact parameter (b)
0.701
Transit mid-time (BJD)
2,459,822.3763
Angular separation (arcsec)
1.63000
Eq. Temperature
586K
(313 °C)
Insolation (S⊕)
20.80
Earth = 1.00
Earth Similarity (ESI)
0.555
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
Lustig Yaeger et al. 2023Instrument
TESS CCD Array
Publication
2023-08
Observation locale
Space
Discovery cohort
Planets confirmed in 2023 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: LHS 475
Spectral Class
M-type red dwarf
Effective Temperature
3,300 K — cooler than the Sun (5,778 K)
Estimated Age
—
Stellar Radius
0.279 R☉
Stellar Mass
0.262 M☉
Metallicity [Fe/H]
—
Extended Stellar Properties
Surface gravity (log g)
5.000 dex
Stellar density
18.400 g/cm³
Systemic radial velocity
-10.30 km/s
Rotation period
79.32 days
Multi-band Host Photometry — 7 bands
Astrometric Data
Parallax
80.090 mas
Total Proper Motion
1,276.923 mas/yr
PM Right Ascension
342.18 mas/yr
PM Declination
-1,230.22 mas/yr
Galactic Cartesian (pc)
x = 0.045 · y = -0.121 · z = -0.992
Equatorial (J2000)
RA 290.23794° · Dec -82.55979°
Galactic ℓ, b
311.282° · -27.836°
Ecliptic λ, β
275.056° · -59.477°
HTM-20 index
-998719909
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EPIC 206215704 b
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