 Artist's impression of 61 Virginis b as a hotsuper-Earth, with some sporadic volcanic activity. | |
| Discovery | |
|---|---|
| Discovered by | Vogtet al. |
| Discovery site | Keck Observatory Anglo-Australian Observatory |
| Discovery date | 14 December 2009 |
| Radial velocity | |
| Orbital characteristics | |
| Apastron | 0.056163AU |
| Periastron | 0.044239AU |
| 0.050201±0.000005AU | |
| Eccentricity | 0.12±0.11 |
| 4.2150±0.0006d 101.16h | |
Averageorbital speed | 130.01 |
| 2453369.166 | |
| 105±54 | |
| Star | 61 Virginis |
| Physical characteristics | |
| ~1.6R🜨 | |
| Mass | ≥ 5.1ME |
| Temperature | 1,054 K (781 °C; 1,438 °F) |
61 Virginis b (abbreviated61 Vir b) is anextrasolar planet, orbiting the 5thmagnitudeG-type star61 Virginis, inVirgo. This planet has aminimum mass of 5.1 times that of Earth and is an example of asuper-Earth planet. It orbits very close to the star, at a distance of 0.050201 AU with an eccentricity of 0.12. This planet was discovered on 14 December 2009 using theradial velocity method taken atKeck andAnglo-Australian Observatories.[1][2]
61 Virginis b is asuper-Earth, an exoplanet with a radius and mass bigger than Earth, but smaller than that of the ice giantsNeptune andUranus. It has anequilibrium temperature of 1,054 K (781 °C; 1,438 °F).[3] It has an estimatedminimum mass of around 5.1ME, and a potential radius of 1.6R🜨, based on its mass.
The planet orbits a (G-type)star named61 Virginis, orbited by a total of three planets.[1] The star has a mass of 0.94M☉ and a radius of 0.98R☉. It has a temperature of 5531K and is about 8.96 billion years old.[1] In comparison, theSun is 4.6 billion years old[4] and has a temperature of 5778 K.[5] The star has slightly less metals then the Sun, with ametallicity ([Fe/H]) of −0.03, or 94% of the solar amount.[1] Its luminosity (L☉) is 80% that of the Sun.[1]
The star'sapparent magnitude, or how bright it appears from Earth's perspective, is 4.74. Therefore, it can be seen with the naked eye.
61 Virginis b orbits its host star with an orbital period of 4.21 days at a distance of about 0.05AU (compared toMercury's from the Sun, which is 0.38 AU). It receives 296.5 times moresunlight that Earth does from the Sun.[3]
The planet may be tidally locked meaning that there is a permanent day side and a permanent night side.
The search for 61 Virginis b started when its host star was chosen an ideal target for a planet search using theradial velocity method (in which the gravitational pull of a planet on its star is measured by observing the resultingDoppler shift), as stellar activity would not overly mask or mimicDoppler spectroscopy measurements. It was also confirmed that 61 Virginis is neither a binary star nor a quickly rotating star, commonfalse positives when searching for transiting planets.
Analysis of the resulting data found that the radial velocity variations most likely indicated the existence of a planet.[1] The net result was an estimate of a 5.1ME planetary companion orbiting the star at a distance of 0.05 AU with an eccentricity of 0.12.
An attempt to determine if the planettransits its host star using theSpitzer Space Telescope unfortunately failed due to technical issues related to the brightness of the star.[6]
