| HD 221287 b / Pipitea | |
| Discoverer: | Dominique Naef et al. |
| Discovery Site: |  Chile |
| Discovered: | March 5, 2007 |
| Discovery Method: | HARPS |
| Apsis: | astron |
| Aphelion: | 1.35AU |
| Perihelion: | 1.15AU |
| Semimajor: | 1.25± |
| Eccentricity: | 0.08 ± 0.11 |
| Period: | 456.1 ± 6.5 d 1.2487 y |
| Time Periastron: | 2,453,263 ± 100 |
| Arg Peri: | 98 ± 72 |
| Semi-Amplitude: | 71 ± 13 |
| Star: | HD 221287 |
| Mass: | >3.12 ± 0.78 (992) |
HD 221287 b, also known as Pipitea, is an exoplanet that orbits HD 221287, approximately 173 light years away in the constellation of Tucana. This planet has mass >3.12 MJ (>992 M) and orbits in a habitable zone at 1.25 AUs (6.06 μpc) from the star, taking 1.25 years to orbit at 29.9 km/s around the star. Dominique Naef discovered this planet in early 2007 by using HARPS spectrograph located in Chile.
Based on a probable 10−4 fraction of the planet mass as a satellite,[1] the planet can have a Mars-sized moon with habitable surface.[2] On the other hand, this mass can be distributed into many small satellites as well.
It was named "Pipitea" by representatives of the Cook Islands in the IAU's 2019 NameExoWorlds contest, with the comment "Pipitea is a small, white and gold pearl found in Penrhyn lagoon in the northern group of the Cook Islands."[3]
From Luminosity and distance irridance can be calculated: [4]
| Planet Distance | Insolation (W/m2) | % of Earth's |
|---|---|---|
| Earth's Aphelion Flux | 1321.544 | 96.74% |
| HD 221287 b Apastron flux | 1,351.050 | 98.90% |
| Earth's Average Flux [5] | 1366.079 | 100.00% |
| Earth's Perihelion Flux | 1412.903 | 103.43% |
| HD 221287 b Average flux [6] | 1,575.865 | 115.36% |
| HD 221287 b Periastron flux | 1,861.844 | 136.29% |
| Venus' Aphelion Flux | 2585.411 | 188.72% |
| Venus' Average Flux | 2620.693 | 191.30% |
| Venus' Perihelion Flux | 2656.70 | 193.93% |
\begin{smallmatrix}L=4\piR2\sigma
| 4 | |
| T | |
| \rmeff |
\end{smallmatrix}
\begin{smallmatrix}L\end{smallmatrix}
\begin{smallmatrix}R\end{smallmatrix}
\begin{smallmatrix}T\rm\end{smallmatrix}
\begin{smallmatrix}\sigma\end{smallmatrix}
fp=
| (1.80245 x 3.0572 x 1025) | |
| ((1.25-(1.25 x 0.08)) x 149597870700)2 |