Key parameters at a glance
- A radius of 14.78 Earth radii
- A mass of 166.86 Earth masses
- Surface gravity around 0.76 g
- An orbital period of 4.465 days
- Semi-major axis 0.0556 AU
- Equilibrium temperature 1,322 K (1049 °C)
- Distance from Earth 518.52 light-years
- Earth Similarity Index 0.083
- Travel time at Voyager 1 speed 9,144,092 years
HAT-P-1 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#255of 1771
top 14.3%
This planet
14.78R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | HAT-P-1 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 14.78 | 11.21 |
| Mass (M⊕) | 1.00 | 166.86 | 317.83 |
| Density (g/cm³) | 5.51 | 0.28 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.76 | 2.53 |
| Insolation (S⊕) | 1.00 | 259.69 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 166.861 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 166.543 M⊕ | Lower bound from radial-velocity fitting. |
| Computed mass | 167.000 M⊕ | Model-computed mass (e.g. from mass-radius relation). |
Star Catalogue Identifiers
TIC
TIC 346338552
Gaia DR2
Gaia DR2 1928431764627661440
Gaia DR3
Gaia DR3 1928431764627661440
System
HAT-P-1
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 4.47 Earth days (1.2% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0556 AU.
Transit Fingerprint
Depth
1.444 %
Duration
2.850 h
Impact parameter b
0.750
Rp / R★
0.118020
Transit midpoint (BJD)
2,453,979.9320
Photometric dip
Transit produces a flux drop of 14,440 ppm lasting ≈ 2.85 h.
Extended Orbital Architecture
Planet / star radius ratio
0.118020
Semi-major axis / stellar radius
9.853
Impact parameter (b)
0.750
RV semi-amplitude (K)
58.900 m/s
Transit mid-time (BJD)
2,453,979.9320
Long. of periastron (ω)
253.10°
Sky-projected obliquity (λ)
3.70°
Angular separation (arcsec)
0.35000
Eq. Temperature
1,322K
(1049 °C)
Insolation (S⊕)
259.69
Earth = 1.00
Earth Similarity (ESI)
0.083
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
Bakos et al. 2007Instrument
2K CCD Sensor
Publication
2007-02
Observation locale
Ground
Host System: HAT-P-1
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,980 K — hotter than the Sun (5,778 K)
Estimated Age
3.60 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
1.174 R☉
Stellar Mass
1.151 M☉
Metallicity [Fe/H]
0.13
Extended Stellar Properties
Surface gravity (log g)
4.359 dex
Stellar density
0.908 g/cm³
Systemic radial velocity
-2.98 km/s
Rotational v·sin i
2.20 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 12 bands
Astrometric Data
Parallax
6.262 mas
Total Proper Motion
52.838 mas/yr
PM Right Ascension
32.38 mas/yr
PM Declination
-41.75 mas/yr
Galactic Cartesian (pc)
x = 0.752 · y = -0.209 · z = 0.625
Equatorial (J2000)
RA 344.44536° · Dec 38.67492°
Galactic ℓ, b
99.792° · -19.036°
Ecliptic λ, β
4.292° · 41.042°
HTM-20 index
560587143
Observation Record
Photometric series
16
RV measurements
7
Transmission spectra
7
Emission spectra
4
Archive notes
2
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