Key parameters at a glance
- A radius of 12.02 Earth radii
- A mass of 230.11 Earth masses
- Surface gravity around 1.59 g
- An orbital period of 2.298 days
- Semi-major axis 0.0300 AU
- Equilibrium temperature 1,028 K (755 °C)
- Distance from Earth 659.33 light-years
- Earth Similarity Index 0.138
- Travel time at Voyager 1 speed 11,627,299 years
- Almost certainly tidally locked to its host star given the close orbit
HAT-P-68 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#1493of 1771
top 84.2%
This planet
12.02R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | HAT-P-68 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 12.02 | 11.21 |
| Mass (M⊕) | 1.00 | 230.11 | 317.83 |
| Density (g/cm³) | 5.51 | 0.73 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.59 | 2.53 |
| Insolation (S⊕) | 1.00 | 184.80 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 230.109 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 63189173
Gaia DR2
Gaia DR2 675443053940533760
Gaia DR3
Gaia DR3 675443053940533760
System
HAT-P-68
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 2.30 Earth days (0.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0300 AU.
Transit Fingerprint
Depth
3.083 %
Duration
2.087 h
Impact parameter b
0.212
Rp / R★
0.164400
Transit midpoint (BJD)
2,456,614.2036
Photometric dip
Transit produces a flux drop of 30,832 ppm lasting ≈ 2.09 h.
Extended Orbital Architecture
Planet / star radius ratio
0.164400
Semi-major axis / stellar radius
9.600
Impact parameter (b)
0.212
RV semi-amplitude (K)
143.400 m/s
Transit mid-time (BJD)
2,456,614.2036
Angular separation (arcsec)
0.14800
Eq. Temperature
1,028K
(755 °C)
Insolation (S⊕)
184.80
Earth = 1.00
Earth Similarity (ESI)
0.138
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
Lindor et al. 2021Instrument
2K CCD Sensor
Publication
2021-02
Observation locale
Ground
Host System: HAT-P-68
Spectral Class
K-type orange
Effective Temperature
4,508 K — cooler than the Sun (5,778 K)
Estimated Age
11.10 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.670 R☉
Stellar Mass
0.679 M☉
Metallicity [Fe/H]
-0.06
Extended Stellar Properties
Surface gravity (log g)
4.615 dex
Stellar density
3.165 g/cm³
Rotational v·sin i
0.00 km/s
Rotation period
24.59 days
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
4.918 mas
Total Proper Motion
23.701 mas/yr
PM Right Ascension
-23.66 mas/yr
PM Declination
-1.47 mas/yr
Galactic Cartesian (pc)
x = -0.436 · y = 0.803 · z = 0.406
Equatorial (J2000)
RA 118.48315° · Dec 23.93822°
Galactic ℓ, b
197.144° · 23.834°
Ecliptic λ, β
115.876° · 3.022°
HTM-20 index
189523782
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