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HD 221287 b / Pipitea

Discovery
Discovered by	Dominique Naef et al.
Discovery site	Chile
Discovery date	March 5, 2007
Detection method	HARPS
Orbital characteristics
Apastron	1.35 AU (202,000,000 km)
Periastron	1.15 AU (172,000,000 km)
Semi-major axis	1.25 ± 0.04 AU (187,000,000 ± 6,000,000 km)
Eccentricity	0.08 ± 0.11
Orbital period (sidereal)	456.1 ± 6.5 d 1.2487 y
Time of periastron	2,453,263 ± 100
Argument of periastron	98 ± 72
Semi-amplitude	71 ± 13
Star	HD 221287
Physical characteristics
Mass	>3.12 ± 0.78 MJ (992 ME)

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 M_J (>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 fraction of the planet mass as a satellite, the planet can have a Mars-sized moon with habitable surface. 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."

Insolation data for HD 221287 b

From Luminosity and distance irridance can be calculated:

See also

• HD 100777 b
• HD 190647 b

Notes

1. From ${\displaystyle {\begin{smallmatrix}L=4\pi R^{2}\sigma T_{\rm {eff}}^{4}\end{smallmatrix}}}$, where ${\displaystyle {\begin{smallmatrix}L\end{smallmatrix}}}$ is the luminosity, ${\displaystyle {\begin{smallmatrix}R\end{smallmatrix}}}$ is the radius, ${\displaystyle {\begin{smallmatrix}T_{\rm {eff}}\end{smallmatrix}}}$ is the effective surface temperature and ${\displaystyle {\begin{smallmatrix}\sigma \end{smallmatrix}}}$ is the Stefan–Boltzmann constant.
2. Earth's Solar Constant.
3. ${\displaystyle f_{p}={\frac {(1.80245\times 3.0572\times 10^{25})}{((1.25-(1.25\times 0.08))\times 149597870700)^{2}}}}$

References

1. ^ Naef, D.; et al. (2007). "The HARPS search for southern extra-solar planets IX. Exoplanets orbiting HD 100777, HD 190647, and HD 221287". Astronomy and Astrophysics. 470 (2): 721–726. arXiv:0704.0917. Bibcode:2007A&A...470..721N. doi:10.1051/0004-6361:20077361.
2. Canup R.M., Ward W.R. (2006). A common mass scaling for satellite systems of gaseous planets. Nature, 441: 834-839.
3. "The Habitable Exoplanets Catalog: Data of Potential Habitable Worlds". Archived from the original on 2017-12-01. Retrieved 2013-06-23.
4. "Approved names (§ Cook Islands)". Name Exo Worlds. IAU. Retrieved 19 December 2019.

External links

• "Notes for planet HD 221287 b". Extrasolar Planets Encyclopaedia. Retrieved 2008-07-21.

v t e Constellation of Tucana
List of stars in Tucana Tucana in Chinese astronomy
Stars	Bayer α β β β γ δ ε ζ η θ ι κ λ λ μ ν π ρ Variable DS HR 8829 HD 4308 5980 7199 (Emiw) 215497 221287 (Poerava) Other AB7 Gliese 54 HV 2112 HV 11417 HV 11423 L 168-9 PMMR 62 SMC 018136
Exoplanets DS Tucanae Ab HD 4308 b HD 7199 b (Hairu) HD 215497 b c HD 219077 b HD 221287 b (Pipitea)
Star clusters	NGC 121 152 176 220 222 231 241 256 265 267 269 290 294 299 306 330 339 346 361 362 371 376 395 411 416 419 422 456 458 460 465 Other ξ (47)
Nebulae E0102
Galaxies	NGC 53 360 406 432 434 440 466 484 7329 Other ESO 148-2 ISOHDFS 27 Tucana Dwarf Small Magellanic Cloud (partly in Hydrus)
Category

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