Planet GJ 229 Ba

Detailed information about planet GJ 229 Ba and its parameters.

Planet

Name
GJ 229 Ba
Planet Status
Confirmed
Discovered in
1995
Update
2024-10-22
Mass
Mass*sin(i)
Semi-Major Axis
Orbital Period
Eccentricity
ω
Tperi
Radius
Inclination
Detection Method
Imaging
Mass Meas. Method
Astrometry
Radius Meas. Method
Flux
Primary transit
Secondary transit
λ
Impact Parameter b
Time Vr=0
Velocity Semiamplitude K
Calculated temperature
Measured temperature
Hottest point longitude
Geometric albedo
Surface gravity log(g/gH)
Alternate Names
Gliese 229 b, HD 42581 b
Data Source Type Result Value Result Figure Notes Reference
Molecule Data Source Type Result Value Result Figure Notes Reference
CH4
Modeling Detected -3.352 ( +0.018 -0.017 ) 2022 - HOWE A.R.
CO
Modeling Detected -3.805 ( +0.11 -0.113 ) 2022 - HOWE A.R.
CO2
Modeling Detected -7.9 ( +2.6 -2.7 ) 2022 - HOWE A.R.
H2O
Modeling Detected -3.43 ( +0.017 -0.016 ) 2022 - HOWE A.R.
H2S
Modeling Detected -5.6 ( +0.9 -4.5 ) 2022 - HOWE A.R.
K
Modeling Detected -5.942 ( +0.11 -0.014 ) 2022 - HOWE A.R.
Na
Modeling Detected -5.942 ( +0.11 -0.014 ) 2022 - HOWE A.R.
NH3
Modeling Detected -4.504 ( +0.021 -0.024 ) 2022 - HOWE A.R.

Feng et al. (2022) list GJ 229 B as "HD 42581 d" following separation order of substellar components. However the more correct designation is "HD 42581 b" according to the chronology of discoveries (1995).
Howe et al. (2022) provide a lower mass estimate (41.6 ± 3.3 MJup for an age > 1 Gyr).
17 Oct. 2024: Brandt et al. (2021) estimated a mass of 71.4 ± 0.6MJup for GJ 229 B also considering a binary nature for the object. Kawashima et al. (2024) provide support to the binary model. Accordingly taking 71.4 ± 0.6MJup as total mass and 1.3 RJup as total radius, GJ 229 B is likely an equal-mass substellar binary of about 36 MJup and 0.92 RJup for each component (for Mb = Ms/2 and Rb = Rs/ √ 2, where Mb and Ms are namely the mass estimate for a binary and a single object as well as Rb and Rs concern the radius estimate for a binary and a single object).
18 Oct. 2024: Gj 229 B is confirmed as binary brown dwarf with individual spectral types close to T7 and T8 respectively.

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