Key parameters at a glance
- A radius of 10.58 Earth radii
- A mass of 241.55 Earth masses
- Surface gravity around 2.16 g
- An orbital period of 3.800 days
- Semi-major axis 0.0412 AU
- Equilibrium temperature 818 K (545 °C)
- Distance from Earth 468.53 light-years
- Earth Similarity Index 0.195
- Travel time at Voyager 1 speed 8,262,462 years
- Almost certainly tidally locked to its host star given the close orbit
HAT-P-54 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#1718of 1771
top 97.0%
This planet
10.58R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | HAT-P-54 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 10.58 | 11.21 |
| Mass (M⊕) | 1.00 | 241.55 | 317.83 |
| Density (g/cm³) | 5.51 | 1.12 | 1.33 |
| Surface Gravity (g) | 1.00 | 2.16 | 2.53 |
| Insolation (S⊕) | 1.00 | 88.67 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 241.551 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 284326455
Gaia DR2
Gaia DR2 3383298227579280640
Gaia DR3
Gaia DR3 3383298227579280640
System
HAT-P-54
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 3.80 Earth days (1.0% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0412 AU.
Transit Fingerprint
Depth
2.546 %
Duration
1.811 h
Impact parameter b
0.741
Rp / R★
0.157200
Transit midpoint (BJD)
2,456,299.3037
Photometric dip
Transit produces a flux drop of 25,455 ppm lasting ≈ 1.81 h.
Extended Orbital Architecture
Planet / star radius ratio
0.157200
Semi-major axis / stellar radius
14.340
Impact parameter (b)
0.741
RV semi-amplitude (K)
132.600 m/s
Transit mid-time (BJD)
2,456,299.3037
Angular separation (arcsec)
0.28700
Eq. Temperature
818K
(545 °C)
Insolation (S⊕)
88.67
Earth = 1.00
Earth Similarity (ESI)
0.195
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
Bakos et al. 2015Instrument
2K CCD Sensor
Publication
2015-04
Observation locale
Ground
Discovery cohort
Planets confirmed in 2015 at HATNet (7 shown).
Host System: HAT-P-54
Spectral Class
K-type orange
Effective Temperature
4,390 K — cooler than the Sun (5,778 K)
Estimated Age
3.90 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.617 R☉
Stellar Mass
0.645 M☉
Metallicity [Fe/H]
-0.13
Extended Stellar Properties
Surface gravity (log g)
4.667 dex
Stellar density
2.083 g/cm³
Systemic radial velocity
31.85 km/s
Rotational v·sin i
2.35 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 12 bands
Astrometric Data
Parallax
6.933 mas
Total Proper Motion
33.237 mas/yr
PM Right Ascension
-0.07 mas/yr
PM Declination
-33.24 mas/yr
Galactic Cartesian (pc)
x = -0.155 · y = 0.889 · z = 0.430
Equatorial (J2000)
RA 99.89799° · Dec 25.48240°
Galactic ℓ, b
188.784° · 8.898°
Ecliptic λ, β
98.930° · 2.350°
HTM-20 index
-342105145
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