Key parameters at a glance
- A radius of 13.59 Earth radii
- A mass of 198.95 Earth masses
- Surface gravity around 1.08 g
- An orbital period of 3.257 days
- Semi-major axis 0.0434 AU
- Equilibrium temperature 1,384 K (1111 °C)
- Distance from Earth 1,308.93 light-years
- Earth Similarity Index 0.088
- Travel time at Voyager 1 speed 23,082,909 years
HAT-P-28 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#657of 1771
top 37.0%
This planet
13.59R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | HAT-P-28 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 13.59 | 11.21 |
| Mass (M⊕) | 1.00 | 198.95 | 317.83 |
| Density (g/cm³) | 5.51 | 0.44 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.08 | 2.53 |
| Insolation (S⊕) | 1.00 | 554.71 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 198.953 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 53728859
Gaia DR2
Gaia DR2 363702817083391232
Gaia DR3
Gaia DR3 363702817083391232
System
HAT-P-28
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 3.26 Earth days (0.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0434 AU.
Transit Fingerprint
Depth
1.472 %
Duration
3.218 h
Impact parameter b
0.299
Rp / R★
0.113000
Transit midpoint (BJD)
2,455,417.5983
Photometric dip
Transit produces a flux drop of 14,719 ppm lasting ≈ 3.22 h.
Extended Orbital Architecture
Planet / star radius ratio
0.113000
Semi-major axis / stellar radius
8.430
Impact parameter (b)
0.299
RV semi-amplitude (K)
84.700 m/s
Transit mid-time (BJD)
2,455,417.5983
Long. of periastron (ω)
233.00°
Angular separation (arcsec)
0.10800
Eq. Temperature
1,384K
(1111 °C)
Insolation (S⊕)
554.71
Earth = 1.00
Earth Similarity (ESI)
0.088
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
Buchhave et al. 2011Instrument
2K CCD Sensor
Publication
2011-06
Observation locale
Ground
Discovery cohort
Planets confirmed in 2011 at HATNet (10 shown).
Host System: HAT-P-28
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,680 K — cooler than the Sun (5,778 K)
Estimated Age
6.10 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
1.103 R☉
Stellar Mass
1.025 M☉
Metallicity [Fe/H]
0.12
Extended Stellar Properties
Surface gravity (log g)
4.360 dex
Stellar density
1.244 g/cm³
Systemic radial velocity
43.88 km/s
Rotational v·sin i
0.20 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
2.463 mas
Total Proper Motion
25.678 mas/yr
PM Right Ascension
25.52 mas/yr
PM Declination
2.86 mas/yr
Galactic Cartesian (pc)
x = 0.801 · y = 0.185 · z = 0.570
Equatorial (J2000)
RA 13.00092° · Dec 34.72840°
Galactic ℓ, b
123.064° · -28.143°
Ecliptic λ, β
26.323° · 26.688°
HTM-20 index
442859679
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