Key parameters at a glance
- A radius of 11.31 Earth radii
- A mass of 378.22 Earth masses
- Surface gravity around 2.96 g
- An orbital period of 1.541 days
- Semi-major axis 0.0234 AU
- Equilibrium temperature 1,134 K (861 °C)
- Distance from Earth 697.23 light-years
- Earth Similarity Index 0.139
- Travel time at Voyager 1 speed 12,295,596 years
- Almost certainly tidally locked to its host star given the close orbit
Qatar-9 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#1614of 1771
top 91.1%
This planet
11.31R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | Qatar-9 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 11.31 | 11.21 |
| Mass (M⊕) | 1.00 | 378.22 | 317.83 |
| Density (g/cm³) | 5.51 | 1.43 | 1.33 |
| Surface Gravity (g) | 1.00 | 2.96 | 2.53 |
| Insolation (S⊕) | 1.00 | 210.67 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 378.218 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 149918151
Gaia DR2
Gaia DR2 1048109222955337600
Gaia DR3
Gaia DR3 1048109222955337600
System
Qatar-9
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 1.54 Earth days (0.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0234 AU.
Transit Fingerprint
Depth
2.731 %
Duration
1.867 h
Impact parameter b
0.097
Rp / R★
0.148900
Transit midpoint (BJD)
2,458,227.7564
Photometric dip
Transit produces a flux drop of 27,310 ppm lasting ≈ 1.87 h.
Extended Orbital Architecture
Planet / star radius ratio
0.148900
Semi-major axis / stellar radius
7.236
Impact parameter (b)
0.097
RV semi-amplitude (K)
259.000 m/s
Transit mid-time (BJD)
2,458,227.7564
Angular separation (arcsec)
0.10900
Eq. Temperature
1,134K
(861 °C)
Insolation (S⊕)
210.67
Earth = 1.00
Earth Similarity (ESI)
0.139
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
Alsubai et al. 2019Instrument
FLI ProLine 4K CCD Sensor
Publication
2019-06
Observation locale
Ground
Discovery cohort
Planets confirmed in 2019 at Qatar (3 shown).
Host System: Qatar-9
Spectral Class
K-type orange
Effective Temperature
4,309 K — cooler than the Sun (5,778 K)
Estimated Age
7.50 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.696 R☉
Stellar Mass
0.719 M☉
Metallicity [Fe/H]
0.25
Extended Stellar Properties
Surface gravity (log g)
4.610 dex
Stellar density
3.015 g/cm³
Systemic radial velocity
2.92 km/s
Rotational v·sin i
4.30 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
4.649 mas
Total Proper Motion
31.878 mas/yr
PM Right Ascension
-23.74 mas/yr
PM Declination
-21.27 mas/yr
Galactic Cartesian (pc)
x = -0.458 · y = 0.160 · z = 0.874
Equatorial (J2000)
RA 160.74810° · Dec 60.96412°
Galactic ℓ, b
146.527° · 49.867°
Ecliptic λ, β
132.809° · 47.605°
HTM-20 index
-638480259
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