HD 221287

{{Starbox observe

| epoch = J2000

| constell = Tucana

| ra = {{RA|23|31|20.33819}}

| dec = {{DEC|−58|12|35.0324}}

| appmag_v = 7.82

}}

{{Starbox character

| type =

| class = F7V

| b-v = {{Val|0.513|0.008}}

| variable =

}}

{{Starbox astrometry

| radial_v = {{Val|−21.90|0.18}}

| prop_mo_ra = {{val|181.160|0.059}}

| prop_mo_dec = {{val|−5.297|0.060}}

| parallax = 17.8529

| p_error = 0.0402

| parallax_footnote =

| absmag_v = 4.11

}}

{{Starbox detail

| source =

| mass = {{Val|1.209|0.034|0.038}}

| radius = {{Val|1.183|0.020|0.019}}

| gravity = {{Val|4.374|0.013}}

| luminosity = {{Val|1.944|0.005|0.007}}

| temperature = {{Val|6440|100|fmt=commas}}

| metal_fe = {{Val|+0.13|0.149}}

| rotational_velocity = {{Val|2.9|0.2}}

| rotation = {{Val|5|2}}

| age_myr = {{Val|763|613|474}} or 1,300

}}

{{Starbox catalog

| names = Poerava, {{odlist | 2MASS=J23312032-5812350 | CD=−58°8579 | HD=221287 | HIP=116084 | SAO=247912 | TYC=8838-463-1 }}

}}

{{Starbox reference

| Simbad = HD+221287

}}

HD 221287, named Poerava, is a star in the southern constellation of Tucana. It has a yellow-white hue but is too faint to be viewed with the naked eye, having an apparent visual magnitude of 7.82. This object is located at a distance of 183 light years from the Sun, as determined from its parallax. It is drifting closer with a radial velocity of −22 km/s.

This object is an F-type main-sequence star with a stellar classification of F7V. It is relatively young with age estimates of 763 million and 1.3 billion years, and possesses an active chromosphere. Cool spots on the surface are generating a radial-velocity signal that is modulated by the rotation period of around five days. The star is 18% larger and 20% more massive than the Sun. It is radiating 1.9 times the luminosity of the Sun from its photosphere at an effective temperature of 6,440 K.

Name

The star was given the designation "HD 221287" before being named Poerava by representatives of the Cook Islands in the IAU's 2019 NameExoWorlds contest, with the comment "Poerava is the word in the Cook Islands Maori language for a large mystical black pearl of utter beauty and perfection."{{cite web|url=http://www.nameexoworlds.iau.org/final-results|title=Approved names (§ Cook Islands)|website=Name Exo Worlds|publisher=IAU|access-date=19 December 2019}}

Planetary system

On March 5, 2007, the astronomer Dominique Naef used the HARPS spectrograph to uncover the exoplanetary companion designated HD 221287 b (among others). Using the amplitude from observations with HARPS, he calculated a minimum mass of 3.12 times that of Jupiter, making this a superjovian. This planet orbits 25% further from the star than Earth is from the Sun, with a low eccentricity. In 2024, astrometric measurements revealed that this object might be instead a brown dwarf, with a mass between {{jupiter mass|10 and 20}} at 68% confidence, or between {{jupiter mass|3 and 40}} at 99.5% confidence.

Stability analysis reveals that the orbits of Earth–sized planets in HD 221287 b's Trojan points, located 60 degrees ahead and behind the planet in its orbit, would be stable for long periods of time.

{{OrbitboxPlanet begin

| table_ref =

}}

{{OrbitboxPlanet

| exoplanet = b / Pipitea

| mass = {{Val|3|-|40}}

| period = {{Val|456.1|6.5}}

| semimajor = {{Val|1.25|0.04}}

| eccentricity = {{Val|0.08|0.11}}

}}

References

{{Reflist|refs=

{{cite journal

| title=Spectroscopic Parameters and atmosphEric ChemIstriEs of Stars (SPECIES). I. Code description and dwarf stars catalogue

| last1=Soto | first1=M. G. | last2=Jenkins | first2=J. S.

| journal=Astronomy & Astrophysics

| volume=615 | id=A76 | pages=28 | date=July 2018

| arxiv=1801.09698 | bibcode=2018A&A...615A..76S

| doi=10.1051/0004-6361/201731533 | s2cid=119107228 }}

{{cite book

| last1=Houk | first1=Nancy

| title=Michigan catalogue of two-dimensional spectral types for the HD stars

| volume=1 | location=Ann Arbor

| publisher=Dept. of Astronomy, University of Michigan

| year=1978 | bibcode=1975mcts.book.....H }}

{{cite journal

| title=XHIP: An extended hipparcos compilation

| journal=Astronomy Letters

| volume=38 | issue=5 | pages=331 | year=2012

| last1=Anderson | first1=E. | last2=Francis | first2=Ch.

| bibcode=2012AstL...38..331A | arxiv=1108.4971

| doi=10.1134/S1063773712050015 | s2cid=119257644

}}

{{Cite journal

| title=The HARPS search for southern extra-solar planets. IX. Exoplanets orbiting HD 100777, HD 190647, and HD 221287

| last1=Naef | first1=M. | last2=Mayor | first2=M.

| last3=Benz | first3=W. | last4=Bouchy | first4=F.

| last5=Lo Curto | first5=G. | last6=Lovis | first6=C.

| last7=Moutou | first7=C. | last8=Pepe | first8=F.

| last9=Queloz | first9=D. | last10=Santos | first10=N. C.

| last11=Udry | first11=S. | display-authors=1

| journal=Astronomy and Astrophysics

| volume=470 | issue=2 | pages=721–726 | year=2007

| arxiv=0704.0917 | bibcode=2007A&A...470..721N | bibcode-access=free

| doi=10.1051/0004-6361:20077361 | doi-access=free }}

{{cite journal

| journal=Astronomy and Astrophysics

| volume=474 | issue=3 | pages=1023–1029

| url=http://www.univie.ac.at/adg/Research/exotro/aa7994-07.pdf

| title=Survey of the stability region of hypothetical habitable Trojan planets

| first1=R. | last1=Schwarz | first2=R. | last2=Dvorak

| first3=Á. | last3=Süli | first4=B. | last4=Érdi

| display-authors=1 | date=November 2007 | doi=10.1051/0004-6361:20077994 | bibcode=2007A&A...474.1023S| doi-access=free }}

{{Cite arXiv|last1=Kiefer |first1=Flavien |last2=Lagrange |first2=Anne-Marie |last3=Rubini |first3=Pascal |last4=Philipot |first4=Florian |date=2024-09-25 |title=Searching for substellar companion candidates with Gaia. II. A catalog of 9,698 planet candidate solar-type hosts |class=astro-ph.EP |eprint=2409.16993}}

}}

Category:F-type main-sequence stars

Category:Planetary systems with one confirmed planet

Category:Tucana

Category:Durchmusterung objects

221287

116084

Poerava

HD 221287

Name

Planetary system

See also

References