Key parameters at a glance
- A radius of 10.54 Earth radii
- A mass of 206.59 Earth masses
- Surface gravity around 1.86 g
- An orbital period of 2.900 days
- Semi-major axis 0.0387 AU
- Equilibrium temperature 1,189 K (916 °C)
- Distance from Earth 438.86 light-years
- Earth Similarity Index 0.124
- Travel time at Voyager 1 speed 7,739,224 years
- Almost certainly tidally locked to its host star given the close orbit
HAT-P-3 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#1724of 1771
top 97.3%
This planet
10.54R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | HAT-P-3 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 10.54 | 11.21 |
| Mass (M⊕) | 1.00 | 206.59 | 317.83 |
| Density (g/cm³) | 5.51 | 0.86 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.86 | 2.53 |
| Insolation (S⊕) | 1.00 | 176.59 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 206.590 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 187.838 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
TIC
TIC 311035838
Gaia DR2
Gaia DR2 1510191594552968832
Gaia DR3
Gaia DR3 1510191594552968832
System
HAT-P-3
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 2.90 Earth days (0.8% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0387 AU.
Transit Fingerprint
Depth
1.200 %
Duration
2.081 h
Impact parameter b
0.615
Rp / R★
0.110910
Transit midpoint (BJD)
2,455,694.7262
Photometric dip
Transit produces a flux drop of 12,000 ppm lasting ≈ 2.08 h.
Extended Orbital Architecture
Planet / star radius ratio
0.110910
Semi-major axis / stellar radius
10.050
Impact parameter (b)
0.615
RV semi-amplitude (K)
89.100 m/s
Transit mid-time (BJD)
2,455,694.7262
Long. of periastron (ω)
107.70°
Sky-projected obliquity (λ)
21.20°
True obliquity (ψ)
75.70°
Angular separation (arcsec)
0.28700
Eq. Temperature
1,189K
(916 °C)
Insolation (S⊕)
176.59
Earth = 1.00
Earth Similarity (ESI)
0.124
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched. 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
Torres et al. 2007Instrument
2K CCD Sensor
Publication
2007-09
Observation locale
Ground
Discovery cohort
Planets confirmed in 2007 at HATNet (4 shown).
Host System: HAT-P-3
Spectral Class
K-type orange
Effective Temperature
5,185 K — cooler than the Sun (5,778 K)
Estimated Age
1.60 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.870 R☉
Stellar Mass
1.060 M☉
Metallicity [Fe/H]
0.27
Extended Stellar Properties
Surface gravity (log g)
4.560 dex
Stellar density
2.280 g/cm³
Systemic radial velocity
-23.38 km/s
Rotational v·sin i
0.46 km/s
Rotation period
19.90 days
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 17 bands
Astrometric Data
Parallax
7.403 mas
Total Proper Motion
31.085 mas/yr
PM Right Ascension
-19.75 mas/yr
PM Declination
-24.01 mas/yr
Galactic Cartesian (pc)
x = -0.601 · y = -0.294 · z = 0.743
Equatorial (J2000)
RA 206.09401° · Dec 48.02857°
Galactic ℓ, b
100.167° · 66.693°
Ecliptic λ, β
177.531° · 53.048°
HTM-20 index
1685331848
Observation Record
Photometric series
24
RV measurements
3
Transmission spectra
4
Emission spectra
3
Archive notes
1
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