Confirmed Exoplanet Discovered 2008

HAT-P-7 b

A gas giant orbiting the f-type yellow-white HAT-P-7, located approximately 1,112.4 light-years from Earth.

Key parameters at a glance

  • A radius of 16.93 Earth radii
  • A mass of 584.81 Earth masses
  • Surface gravity around 2.04 g
  • An orbital period of 2.205 days
  • Semi-major axis 0.0381 AU
  • Equilibrium temperature 2,733 K (2460 °C)
  • Distance from Earth 1,112.45 light-years
  • Earth Similarity Index 0.039
  • Travel time at Voyager 1 speed 19,618,048 years

HAT-P-7 b Planet Profile

Physical Specs

Radius
16.93 R⊕
Radius (Jupiter)
1.510 R♃
Mass
584.81 M⊕
Mass (Jupiter)
1.840 M♃
Density
0.71 g/cm³
Surface Gravity
2.04 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.039
HZ Position Inner
Controversial No

Discovery

Year 2008
Method Transit
Facility HATNet
Telescope Canon 200mm f/1.8L

Size rank in cohort

Rank by radius

#112of 1771

top 6.3%

This planet

16.93R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Metric Earth HAT-P-7 b Jupiter
Radius (R⊕)1.0016.9311.21
Mass (M⊕)1.00584.81317.83
Density (g/cm³)5.510.711.33
Surface Gravity (g)1.002.042.53
Insolation (S⊕)1.004,353.410.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 584.807 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 424865156

Gaia DR2

Gaia DR2 2129256395211984000

Gaia DR3

Gaia DR3 2129256395211984000

System

HAT-P-7

Percentile among Gas Giant cohort

Radius 16.926 R⊕ · percentile 94 / cohort 1771
Mass 584.807 M⊕ · percentile 53 / cohort 1747
Orbital period 2.20 d · percentile 9 / cohort 1533
Distance 341.08 pc · percentile 64 / cohort 1759
ESI 0.039 · percentile 2 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period
2.205 days
Semi-major axis
0.0381 AU
Eccentricity
0.000
Inclination
83.11 °

Year Length

A year here lasts approximately 2.20 Earth days (0.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0381 AU.

Transit Fingerprint

Depth

0.600 %

Duration

3.882 h

Impact parameter b

0.496

Rp / R★

0.075408

Transit midpoint (BJD)

2,454,954.3586

Photometric dip

Transit produces a flux drop of 6,000 ppm lasting ≈ 3.88 h.

Extended Orbital Architecture

Planet / star radius ratio

0.075408

Semi-major axis / stellar radius

4.130

Impact parameter (b)

0.496

RV semi-amplitude (K)

211.800 m/s

Occultation depth

0.007 ppm

Transit mid-time (BJD)

2,454,954.3586

Long. of periastron (ω)

204.00°

Sky-projected obliquity (λ)

182.50°

True obliquity (ψ)

86.30°

Angular separation (arcsec)

0.11200

Eq. Temperature

2,733K

(2460 °C)

Insolation (S⊕)

4,353.41

Earth = 1.00

Earth Similarity (ESI)

0.039

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.

Transit timing variations

Gravitational interactions from neighbours have been detected.

Orbital-brightness modulation

Host star brightness varies with the planet's orbit.

Discovery Paper

Primary reference

Pal et al. 2008

Instrument

2K CCD Sensor

Publication

2008-06

Observation locale

Ground

Discovery cohort

Planets confirmed in 2008 at HATNet (3 shown).

Host System: HAT-P-7

Spectral Class

F-type yellow-white

Effective Temperature

6,389 K — hotter than the Sun (5,778 K)

Estimated Age

1.78 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

2.000 R☉

Stellar Mass

1.560 M☉

Metallicity [Fe/H]

0.26

Extended Stellar Properties

Surface gravity (log g)

4.070 dex

Stellar density

0.270 g/cm³

Systemic radial velocity

-11.00 km/s

Rotational v·sin i

3.80 km/s

Metallicity ratio

[Fe/H]

Distance
341.08 parsec
Light-years 1,112.45 ly
V-band magnitude
10.48 mag
Voyager-speed travel 19,618,048 yr

Multi-band Host Photometry — 14 bands

8.911.010.96B10.48V10.37Gaia10.46Kepler10.03TESS10.94Sloan g10.49Sloan r9.56J9.34H9.33K9.28W19.30W29.28W38.93W4

Astrometric Data

Parallax

2.903 mas

Total Proper Motion

20.337 mas/yr

PM Right Ascension

-18.28 mas/yr

PM Declination

8.91 mas/yr

Galactic Cartesian (pc)

x = 0.253 · y = -0.620 · z = 0.743

Equatorial (J2000)

RA 292.24719° · Dec 47.96954°

Galactic ℓ, b

80.033° · 13.975°

Ecliptic λ, β

312.864° · 68.124°

HTM-20 index

-717500257

Observation Record

Photometric series

13

RV measurements

3

Transmission spectra

3

Emission spectra

10

Archive notes

4

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