Key parameters at a glance
- A radius of 11.90 Earth radii
- A mass of 96.70 Earth masses
- Surface gravity around 0.68 g
- An orbital period of 41.380 days
- Semi-major axis 0.1660 AU
- Distance from Earth 35.92 light-years
- Earth Similarity Index 0.272
- Travel time at Voyager 1 speed 633,516 years
- Almost certainly tidally locked to its host star given the close orbit
1 sibling around GJ 1148
GJ 1148 b shares its host star with 1 other confirmed planet. Side-by-side measurements below.
| Planet | Type | Radius (R⊕) | Mass (M⊕) | Period (d) | Eq. T (K) | Year |
|---|---|---|---|---|---|---|
| GJ 1148 b this | Gas Giant | 11.90 | 96.70 | 41.380 | — | 2010 |
| GJ 1148 c | Neptune-like | 9.71 | 68.06 | 532.580 | — | 2017 |
GJ 1148 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#1526of 1771
top 86.1%
This planet
11.90R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | GJ 1148 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 11.90 | 11.21 |
| Mass (M⊕) | 1.00 | 96.70 | 317.83 |
| Density (g/cm³) | 5.51 | 0.32 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.68 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Minimum mass (M sin i) | 96.700 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
HIP
HIP 57050
TIC
TIC 115869504
Gaia DR2
Gaia DR2 772430527947893632
Gaia DR3
Gaia DR3 772430527947893632
System
GJ 1148
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 41.38 Earth days (11.3% of a terrestrial year) on a highly eccentric trajectory at a mean orbital distance of 0.1660 AU.
Extended Orbital Architecture
RV semi-amplitude (K)
38.370 m/s
Transit mid-time (BJD)
2,454,796.9200
Long. of periastron (ω)
258.10°
Angular separation (arcsec)
15.10000
Eq. Temperature
—
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.272
0 = alien, 1 = Earth-identical
Insufficient insolation data. Close-orbiting tidally-locked around a cool host.
Discovery Paper
Primary reference
Haghighipour et al. 2010Instrument
HIRES Spectrometer
Publication
2010-05
Observation locale
Ground
Discovery cohort
Planets confirmed in 2010 at W. M. Keck Observatory (12 shown).
Host System: GJ 1148
Spectral Class
M-type red dwarf
Effective Temperature
3,287 K — cooler than the Sun (5,778 K)
Estimated Age
—
Stellar Radius
0.359 R☉
Stellar Mass
0.344 M☉
Metallicity [Fe/H]
0.16
Extended Stellar Properties
Surface gravity (log g)
4.866 dex
Stellar density
10.526 g/cm³
Systemic radial velocity
-9.10 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 17 bands
Astrometric Data
Parallax
90.762 mas
Total Proper Motion
582.643 mas/yr
PM Right Ascension
-575.65 mas/yr
PM Declination
-89.97 mas/yr
Galactic Cartesian (pc)
x = -0.732 · y = 0.058 · z = 0.679
Equatorial (J2000)
RA 175.43261° · Dec 42.75159°
Galactic ℓ, b
160.618° · 68.916°
Ecliptic λ, β
156.142° · 36.837°
HTM-20 index
-1865794278
Observation Record
Photometric series
1
RV measurements
1
Stellar spectra
3
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