Key parameters at a glance
- A radius of 1.84 Earth radii
- A mass of 4.57 Earth masses
- Surface gravity around 1.35 g
- An orbital period of 5.007 days
- Semi-major axis 0.0464 AU
- Equilibrium temperature 682 K (409 °C)
- Distance from Earth 151.50 light-years
- Earth Similarity Index 0.420
- Travel time at Voyager 1 speed 2,671,624 years
- Almost certainly tidally locked to its host star given the close orbit
Ross 176 b Planet Profile
Physical Specs
Classification
Planet Type
Super-Earth
Discovery
Size rank in cohort
Rank by radius
#201of 1176
top 17.0%
This planet
1.84R⊕
Super-Earth median
1.60R⊕
Nearest-size peers
| Metric | Earth | Ross 176 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 1.84 | 11.21 |
| Mass (M⊕) | 1.00 | 4.57 | 317.83 |
| Density (g/cm³) | 5.51 | 4.03 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.35 | 2.53 |
| Insolation (S⊕) | 1.00 | 36.20 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 4.570 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 193336820
Gaia DR2
Gaia DR2 2083391813854073856
Gaia DR3
Gaia DR3 2083391813854073856
System
Ross 176
Percentile among Super-Earth cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 5.01 Earth days (1.4% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0464 AU.
Transit Fingerprint
Depth
0.129 %
Duration
1.660 h
Impact parameter b
0.170
Rp / R★
0.029600
Transit midpoint (BJD)
2,459,829.7627
Photometric dip
Transit produces a flux drop of 1,290 ppm lasting ≈ 1.66 h.
Extended Orbital Architecture
Planet / star radius ratio
0.029600
Impact parameter (b)
0.170
RV semi-amplitude (K)
2.550 m/s
Transit mid-time (BJD)
2,459,829.7627
Long. of periastron (ω)
101.00°
Angular separation (arcsec)
0.99900
Eq. Temperature
682K
(409 °C)
Insolation (S⊕)
36.20
Earth = 1.00
Earth Similarity (ESI)
0.420
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.
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
Geraldia Gonzalez et al. 2025Instrument
TESS CCD Array
Publication
2025-08
Observation locale
Space
Discovery cohort
Planets confirmed in 2025 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: Ross 176
Spectral Class
K-type orange
Effective Temperature
4,041 K — cooler than the Sun (5,778 K)
Estimated Age
3.00 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.569 R☉
Stellar Mass
0.577 M☉
Metallicity [Fe/H]
-0.19
Extended Stellar Properties
Surface gravity (log g)
5.070 dex
Stellar density
4.153 g/cm³
Rotational v·sin i
2.00 km/s
Rotation period
33.00 days
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 7 bands
Astrometric Data
Parallax
21.500 mas
Total Proper Motion
305.540 mas/yr
PM Right Ascension
227.02 mas/yr
PM Declination
204.49 mas/yr
Galactic Cartesian (pc)
x = 0.396 · y = -0.551 · z = 0.735
Equatorial (J2000)
RA 305.68974° · Dec 47.30862°
Galactic ℓ, b
84.019° · 5.798°
Ecliptic λ, β
331.708° · 63.306°
HTM-20 index
1948750522
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