TW Hydrae b
From Wikipedia, the free encyclopedia
New study: Atacama Large Millimeter Array
GermanyNew study:
ChileNew study: September 2016
| Discovery | |
|---|---|
| Discovered by | First: Setiawan et al. New study: Atacama Large Millimeter Array |
| Discovery site | First: Germany New study: Chile |
| Discovery date | First: December 2007 (disproven) New study: September 2016 |
| Orbital characteristics | |
| 22 AU (3.3×109 km) | |
| Star | TW Hydrae |
| Physical characteristics | |
| ~4.25 R🜨 | |
| Mass | 23.72[1] M🜨 |
| Temperature | ≥40 K (−233.2 °C; −387.7 °F) |
TW Hydrae b is a likely Neptune-like extrasolar planet orbiting at a distance of nearly 22 AU from the young T Tauri star TW Hydrae approximately 176 light-years (54 parsecs, or nearly 1.665×1016 km) away in the constellation of Hydra.
Mass, radius and temperature
TW Hydrae b is an ice giant, an exoplanet with a radius and mass close to that of the ice giants Neptune and Uranus. It may have an equilibrium temperature of around 40 K (−233.2 °C; −387.7 °F). It has an estimated mass of around 22.72 M🜨 (or 1.5 MNeptune) and a possible radius of 4.25 R🜨.
Host star
The planet orbits a (K-type) T Tauri star named TW Hydrae. The star has a mass of 0.8 M☉ and a radius of 1.1 R☉. It has a temperature of 4000 K and is about 9 million years old. In comparison, the Sun is 4.6 billion years old[2] and has a temperature of 5778 K.[3] Its luminosity (L☉) is 28% of that of the Sun.[note 1]
The star's apparent magnitude, or how bright it appears from Earth's perspective, is 11.27. Therefore, it is too dim to be seen with the naked eye.
Orbit
TW Hydrae b orbits its host star at a distance of 22 AU (somewhat less than the orbital distance of Neptune from the Sun, which is 30.11 AU). The orbital period is not known, although taken its similar orbital distance as Neptune, the orbital period may be around the same value.
