HD 40307 e
Extrasolar planet in the constellation Pictor
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HD 40307 e is an extrasolar planet candidate suspected to be orbiting the star HD 40307. It is located 42 light-years away in the direction of the southern constellation Pictor. The planet was discovered by the radial velocity method, using the European Southern Observatory's HARPS apparatus[1][2][3] by a team of astronomers led by Mikko Tuomi at the University of Hertfordshire and Guillem Anglada-Escude of the University of Göttingen, Germany.[4]
| |
| Discovery | |
|---|---|
| Discovered by | Mikko Tuomi et al. |
| Discovery site | La Silla Observatory, Chile |
| Discovery date | October 28, 2012 |
| radial velocity, using HARPS | |
| Orbital characteristics | |
| 0.1886 [0.1782, 0.1969] AU | |
| Eccentricity | 0.06 [0, 0.18][1] |
| 34.62 [34.42, 34.83][1] d | |
| Semi-amplitude | 0.84 [0.53, 1.16][1] |
| Star | HD 40307 |
The existence of the planet was disputed in 2015, as more Doppler spectroscopy data has become available.[5]
Planetary characteristics
Its minimum mass is 3.5 that of Earth - the smallest - and dynamical models suggest it cannot be much more (and so is measured close to edge-on).[1] It further gets roughly the same insolation from its star as Mercury gets from the Sun.[6] Planets like this in that system have been presumed "super-Earth".[7]
However planets b, c, and d are presumed to have migrated in from outer orbits; and planet b is predicted a sub-Neptune.[8] It is likely that this planet formed even further out. Whether it is a sub-Neptune, a super-Venus or even a super-Mercury is unknown.
