Planetary System
The first planet discovered (designated HD 82943 b) was announced in 2000 by a team of French astronomers led by Michel Mayor. The planet orbits its parent star at a mean distance of 1.19 astronomical units (AU) and taking approximately 441 days to complete the orbit. Nearly a year later, a second planet (designated HD 82943 c) was announced by the same discoverers of the previous planet. This planet orbits closer than the other, at a mean distance of 0.746 AU and taking 219 days to complete its orbit. The two known planets appear to have a 2:1 resonance with one another.
Announced in 2001, HD 82943 was found to contain an unusually high amount of Lithium-6. Stars do not naturally contain Lithium-6, but unlike stars, planets never reach temperatures that are high enough to burn their initial content of Lithium-6 (planets should retain Lithium-6). The simplest and most convincing answer to explain this observation is that one or more planets, or at least planetary material, have fallen into the star, sometime after it passed through its early evolutionary stage.
| Companion |
Mass | Semimajor axis |
Orbital period |
Eccentricity | Radius |
|---|---|---|---|---|---|
| c | 2.01 MJ | 0.746 | 219.3 | 0.359 | — |
| b | 1.75 MJ | 1.19 | 441.2 | 0.219 | — |
Read more about this topic: HD 82943
Famous quotes containing the words planetary and/or system:
“We cannot cheat on DNA. We cannot get round photosynthesis. We cannot say I am not going to give a damn about phytoplankton. All these tiny mechanisms provide the preconditions of our planetary life. To say we do not care is to say in the most literal sense that “we choose death.””
—Barbara Ward (1914–1981)
“We now come to the grand law of the system in which we are placed, as it has been developed by the experience of our race, and that, in one word, is SACRIFICE!”
—Catherine E. Beecher (1800–1878)