Key parameters at a glance
- A radius of 10.82 Earth radii
- A mass of 1,722.64 Earth masses
- Surface gravity around 14.72 g
- An orbital period of 9.477 days
- Semi-major axis 0.0914 AU
- Equilibrium temperature 1,198 K (925 °C)
- Distance from Earth 1,118.16 light-years
- Earth Similarity Index 0.141
- Travel time at Voyager 1 speed 19,718,819 years
TOI-172 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#1684of 1771
top 95.0%
This planet
10.82R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | TOI-172 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 10.82 | 11.21 |
| Mass (M⊕) | 1.00 | 1,722.64 | 317.83 |
| Density (g/cm³) | 5.51 | 7.53 | 1.33 |
| Surface Gravity (g) | 1.00 | 14.72 | 2.53 |
| Insolation (S⊕) | 1.00 | 299.00 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 1,722.639 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 1,722.639 M⊕ | Lower bound from radial-velocity fitting. |
| Computed mass | 1,723.489 M⊕ | Model-computed mass (e.g. from mass-radius relation). |
Star Catalogue Identifiers
TIC
TIC 29857954
Gaia DR2
Gaia DR2 6801474136516893184
Gaia DR3
Gaia DR3 6801474136516893184
System
TOI-172
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 9.48 Earth days (2.6% of a terrestrial year) on a highly eccentric trajectory at a mean orbital distance of 0.0914 AU.
Transit Fingerprint
Depth
0.312 %
Duration
4.714 h
Impact parameter b
0.220
Rp / R★
0.055880
Transit midpoint (BJD)
2,458,345.8734
Photometric dip
Transit produces a flux drop of 3,120 ppm lasting ≈ 4.71 h.
Extended Orbital Architecture
Planet / star radius ratio
0.055880
Semi-major axis / stellar radius
11.090
Impact parameter (b)
0.220
RV semi-amplitude (K)
517.600 m/s
Transit mid-time (BJD)
2,458,345.8734
Long. of periastron (ω)
57.10°
Angular separation (arcsec)
0.26700
Eq. Temperature
1,198K
(925 °C)
Insolation (S⊕)
299.00
Earth = 1.00
Earth Similarity (ESI)
0.141
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
Rodriguez et al. 2019Instrument
TESS CCD Array
Publication
2019-05
Observation locale
Space
Discovery cohort
Planets confirmed in 2019 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).
Host System: TOI-172
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,645 K — cooler than the Sun (5,778 K)
Estimated Age
7.40 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
1.777 R☉
Stellar Mass
1.128 M☉
Metallicity [Fe/H]
0.15
Extended Stellar Properties
Surface gravity (log g)
3.993 dex
Stellar density
0.286 g/cm³
Systemic radial velocity
-5.89 km/s
Rotational v·sin i
5.10 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
2.890 mas
Total Proper Motion
54.454 mas/yr
PM Right Ascension
-4.71 mas/yr
PM Declination
-54.25 mas/yr
Galactic Cartesian (pc)
x = 0.649 · y = -0.614 · z = -0.449
Equatorial (J2000)
RA 316.63188° · Dec -26.69287°
Galactic ℓ, b
19.795° · -40.304°
Ecliptic λ, β
311.209° · -9.678°
HTM-20 index
997992071
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