Polaris

File:Polaris alpha ursae minoris.jpg]]

Polaris Aa is an evolved yellow supergiant of spectral type F7Ib with 5.4 solar masses ({{Solar mass|link=y}}). It is the first classical Cepheid to have a mass determined from its orbit. The two smaller companions are Polaris B, a {{Solar mass|1.39}} F3 main-sequence star orbiting at a distance of {{val|2400|ul=astronomical units|fmt=commas}} (AU),{{cite journal|bibcode=2000A&A...360..399W|arxiv = astro-ph/0002406 |title = Polaris: Astrometric orbit, position, and proper motion |journal = Astronomy and Astrophysics |volume = 360 |pages = 399–410 [400–402, 406] |last1 = Wielen |first1 = R. |last2 = Jahreiß |first2 = H. |last3 = Dettbarn |first3 = C. |last4 = Lenhardt |first4 = H. |last5 = Schwan |first5 = H. |year = 2000 }} and Polaris Ab (or P), a very close F6 main-sequence star with a mass of {{Solar mass|1.26}}. Polaris B can be resolved with a modest telescope. William Herschel discovered the star in August 1779 using a reflecting telescope of his own,{{cite book

| title=An Anthology of Visual Double Stars

| display-authors=1 | first1=Bob | last1=Argyle

| first2=Mike | last2=Swan | first3=Andrew | last3=James

| date=August 29, 2019 | page=265 | isbn=9781108601702

| publisher=Cambridge University Press

| url=https://books.google.com/books?id=jSmqDwAAQBAJ&pg=PT265

}} one of the best telescopes of the time. In January 2006, NASA released images, from the Hubble telescope, that showed the three members of the Polaris ternary system.{{cite web|url=https://hubblesite.org/contents/news-releases/2006/news-2006-02.html |title=There's More to the North Star Than Meets the Eye |publisher=Hubblesite.org |date=2006-01-09 |access-date=2020-02-27}}

The variable radial velocity of Polaris A was reported by W. W. Campbell in 1899, which suggested this star is a binary system.{{cite journal

| title=On the variable velocity of Polaris in the line of sight

| last=Campbell | first=W. W.

| journal=Publications of the Astronomical Society of the Pacific

| volume=11 | pages=195–199| date=October 1899

| doi=10.1086/121339 | bibcode=1899PASP...11..195C

| s2cid=122429136 }} Since Polaris A is a known cepheid variable, J. H. Moore in 1927 demonstrated that the changes in velocity along the line of sight were due to a combination of the four-day pulsation period combined with a much longer orbital period and a large eccentricity of around 0.6.{{cite journal

| title=Note on the Longitude of the Lick Observatory

| last=Moore | first=J. H.

| journal=Publications of the Astronomical Society of the Pacific

| volume=39 | issue=230 | page=249 | date=August 1927

| doi=10.1086/123734 | bibcode=1927PASP...39..249M

| s2cid=119469812 | doi-access=free }} Moore published preliminary orbital elements of the system in 1929, giving an orbital period of about 29.7 years with an eccentricity of 0.63. This period was confirmed by proper motion studies performed by B. P. Gerasimovič in 1939.{{cite journal

| title=Orbital Motion of Alpha Ursae Minoris from Radial Velocities

| last=Roemer | first=Elizabeth

| journal=Astrophysical Journal

| volume=141 | page=1415 | date=May 1965

| doi=10.1086/148230 | bibcode=1965ApJ...141.1415R

| doi-access=free}}

As part of her doctoral thesis, in 1955 E. Roemer used radial velocity data to derive an orbital period of 30.46 y for the Polaris A system, with an eccentricity of 0.64.{{cite journal

| title=Parallax and orbital motion of spectroscopic binary Polaris from photographs taken with the 24-inch Sproul refractor.

| last=Wyller | first=A. A.

| journal=Astronomical Journal

| volume=62 | pages=389–393 | date=December 1957

| doi=10.1086/107559 | bibcode=1957AJ.....62..389W }} K. W. Kamper in 1996 produced refined elements with a period of {{val|29.59|0.02|u=years}} and an eccentricity of {{val|0.608|0.005}}.{{cite journal

| title=Polaris Today

| last=Kamper | first=Karl W.

| journal=Journal of the Royal Astronomical Society of Canada

| volume=90 | page=140 | date=June 1996

| bibcode=1996JRASC..90..140K }} In 2019, a study by R. I. Anderson gave a period of {{val|29.32|0.11|u=years}} with an eccentricity of {{val|0.620|0.008}}.{{cite journal

| title=Probing Polaris' puzzling radial velocity signals. Pulsational (in-)stability, orbital motion, and bisector variations

| last=Anderson | first=R. I.

| journal=Astronomy & Astrophysics

| volume=623 | id=A146 | pages=17 | date=March 2019

| doi=10.1051/0004-6361/201834703 | arxiv=1902.08031

| bibcode=2019A&A...623A.146A | s2cid=119467242 }}

There were once thought to be two more widely separated components—Polaris C and Polaris D—but these have been shown not to be physically associated with the Polaris system.{{cite journal|bibcode=2010AJ....139.1968E|title=Chandra Observation of Polaris: Census of Low-mass Companions|journal=The Astronomical Journal|volume=139|issue=5|pages=1968|last1=Evans|first1=Nancy Remage|last2=Guinan|first2=Edward|last3=Engle|first3=Scott|last4=Wolk|first4=Scott J.|last5=Schlegel|first5=Eric|last6=Mason|first6=Brian D.|last7=Karovska|first7=Margarita|last8=Spitzbart|first8=Bradley|year=2010|doi=10.1088/0004-6256/139/5/1968|doi-access=free}}

File:AlphaUMiLightCurve.png for Polaris, plotted from TESS data{{cite web |title=MAST: Barbara A. Mikulski Archive for Space Telescopes |url=https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html |publisher=Space Telescope Science Institute |access-date=8 December 2021}}]]

Polaris Aa, the supergiant primary component, is a low-amplitude Population I classical Cepheid variable, although it was once thought to be a type II Cepheid due to its high galactic latitude. Cepheids constitute an important standard candle for determining distance, so Polaris, as the closest such star, is heavily studied. The variability of Polaris had been suspected since 1852; this variation was confirmed by Ejnar Hertzsprung in 1911.{{cite journal

| last1=Hertzsprung | first1=Ejnar

| title=Nachweis der Veränderlichkeit von α Ursae Minoris

| journal=Astronomische Nachrichten | volume=189 | page=89

| date=August 1911 | language=de

| doi=10.1002/asna.19111890602 | bibcode=1911AN....189...89H

| issue=6 | url=https://zenodo.org/record/1424878

}}

The range of brightness of Polaris is given as 1.86–2.13, but the amplitude has changed since discovery. Prior to 1963, the amplitude was over 0.1 magnitude and was very gradually decreasing. After 1966, it very rapidly decreased until it was less than 0.05 magnitude; since then, it has erratically varied near that range. It has been reported that the amplitude is now increasing again, a reversal not seen in any other Cepheid.

File:Integrated Flux Nebula Surrounding Polaris - Kush Chandaria.jpg]]

The period, roughly 4 days, has also changed over time. It has steadily increased by around 4.5 seconds per year except for a hiatus in 1963–1965. This was originally thought to be due to secular redward (a long term change in redshift that causes light to stretch into longer wavelengths, causing it to appear red) evolution across the Cepheid instability strip, but it may be due to interference between the primary and the first-overtone pulsation modes.{{Cite journal | last1 = Evans | first1 = N. R. | last2 = Sasselov | first2 = D. D. | last3 = Short | first3 = C. I. | doi = 10.1086/338583 | title = Polaris: Amplitude, Period Change, and Companions | journal = The Astrophysical Journal | volume = 567 | issue = 2 | pages = 1121 | year = 2002 |bibcode = 2002ApJ...567.1121E | doi-access = free }}{{Cite journal | last1 = Turner | first1 = D. G. | last2 = Savoy | first2 = J. | last3 = Derrah | first3 = J. | last4 = Abdel-Sabour Abdel-Latif | first4 = M. | last5 = Berdnikov | first5 = L. N. | title = The Period Changes of Polaris | doi = 10.1086/427838 | journal = Publications of the Astronomical Society of the Pacific | volume = 117 | issue = 828 | pages = 207 | year = 2005 |bibcode = 2005PASP..117..207T | doi-access = free }}{{Cite journal | last1 = Neilson | first1 = H. R. | last2 = Engle | first2 = S. G. | last3 = Guinan | first3 = E. | last4 = Langer | first4 = N. | last5 = Wasatonic | first5 = R. P. | last6 = Williams | first6 = D. B. | doi = 10.1088/2041-8205/745/2/L32 | title = The Period Change of the Cepheid Polaris Suggests Enhanced Mass Loss | journal = The Astrophysical Journal | volume = 745 | issue = 2 | pages = L32 | year = 2012 |arxiv = 1201.0761 |bibcode = 2012ApJ...745L..32N | s2cid = 118625176 }} Authors disagree on whether Polaris is a fundamental or first-overtone pulsator and on whether it is crossing the instability strip for the first time or not.{{cite journal|doi=10.3847/2515-5172/aad2d0|title=Toward Ending the Polaris Parallax Debate: A Precise Distance to Our Nearest Cepheid from Gaia DR2|journal=Research Notes of the AAS|volume=2|issue=3|pages=126|year=2018|last1=Engle|first1=Scott G|last2=Guinan|first2=Edward F|last3=Harmanec|first3=Petr|bibcode=2018RNAAS...2..126E|s2cid=126329676 |doi-access=free }}

The temperature of Polaris varies by only a small amount during its pulsations, but the amount of this variation is variable and unpredictable. The erratic changes of temperature and the amplitude of temperature changes during each cycle, from less than 50 K to at least 170 K, may be related to the orbit with Polaris Ab.

Research reported in Science suggests that Polaris is 2.5 times brighter today than when Ptolemy observed it, changing from third to second magnitude.{{cite journal|doi=10.1126/science.304.5678.1740b|pmid=15205508|year=2004|last1=Irion|first1=R|title=American Astronomical Society meeting. As inconstant as the Northern Star|journal=Science|volume=304|issue=5678|pages=1740–1|s2cid=129246155}} Astronomer Edward Guinan considers this to be a remarkable change and is on record as saying that "if they are real, these changes are 100 times larger than [those] predicted by current theories of stellar evolution".

In 2024, researchers led by Nancy Evans at the Harvard & Smithsonian, have studied with more accuracy the Polaris' smaller companion orbit using the CHARA Array. During this observation campaign they have succeeded in shooting Polaris features on its surface; large bright places and dark ones have appeared in close-up images, changing over time. Further, Polaris diameter size has been re-measured to {{solar radius|46}}, using the Gaia distance of {{val|446|1}} light-years, and its mass was determined at {{solar mass|5.13}}.{{Cite journal |last1=Evans |first1=Nancy Remage |last2=Schaefer |first2=Gail H. |last3=Gallenne |first3=Alexandre |last4=Torres |first4=Guillermo |last5=Horch |first5=Elliott P. |last6=Anderson |first6=Richard I. |last7=Monnier |first7=John D. |last8=Roettenbacher |first8=Rachael M. |last9=Baron |first9=Fabien |last10=Anugu |first10=Narsireddy |last11=Davidson |first11=James W. |last12=Kervella |first12=Pierre |last13=Bras |first13=Garance |last14=Proffitt |first14=Charles |last15=Mérand |first15=Antoine |date=2024-08-01 |title=The Orbit and Dynamical Mass of Polaris: Observations with the CHARA Array |bibcode=2024ApJ...971..190E |journal=The Astrophysical Journal |volume=971 |issue=2 |pages=190 |doi=10.3847/1538-4357/ad5e7a |doi-access=free |arxiv=2407.09641 |issn=0004-637X}}

{{main|Pole star}}

File:Polaris-clock face.jpg

File:Star Trail above Beccles - geograph.org.uk - 1855505.jpg with Polaris in the center.]]

File:Dipper polaris cass.png Cassiopeia and the Big Dipper.]]

Because Polaris lies nearly in a direct line with the Earth's rotational axis above the North Pole, it stands almost motionless in the sky, and all the stars of the northern sky appear to rotate around it. It thus provides a nearly fixed point from which to draw measurements for celestial navigation and for astrometry. The elevation of the star above the horizon gives the approximate latitude of the observer.

In 2018 Polaris was 0.66° (39.6 arcminutes) away from the pole of rotation (1.4 times the Moon disc) and so revolves around the pole in a small circle 1.3° in diameter. It will be closest to the pole (about 0.45 degree, or 27 arcminutes) soon after the year 2100.{{cite journal |bibcode=1990JBAA..100..212M |title=Polaris and the North Pole |last1=Meeus |first1=J. |journal=Journal of the British Astronomical Association |year=1990 |volume=100 |page=212 }} Because it is so close to the celestial north pole, its right ascension is changing rapidly due to the precession of Earth's axis, going from 2.5h in AD 2000 to 6h in AD 2100. Twice in each sidereal day Polaris's azimuth is true north; the rest of the time it is displaced eastward or westward, and the bearing must be corrected using tables or a rule of thumb. The best approximation is made using the leading edge of the "Big Dipper" asterism in the constellation Ursa Major. The leading edge (defined by the stars Dubhe and Merak) is referenced to a clock face, and the true azimuth of Polaris worked out for different latitudes.

The apparent motion of Polaris towards and, in the future, away from the celestial pole, is due to the precession of the equinoxes.{{cite book | title=Norton's Star Atlas | date=2004 | publisher=Pearson Education | isbn=978-0-13-145164-3 | editor-last=Ridpath | editor-first=Ian | location=New York | page=[https://archive.org/details/nortonsstaratlas00ianr/page/5 5] | quote=Around 4800 years ago Thuban ({{GreekFont|α}} Draconis) lay a mere 0°.1 from the pole. Deneb ({{GreekFont|α}} Cygni) will be the brightest star near the pole in about 8000 years' time, at a distance of 7°.5. | url-access=registration | url=https://archive.org/details/nortonsstaratlas00ianr/page/5 }} The celestial pole will move away from α UMi after the 21st century, passing close by Gamma Cephei by about the 41st century, moving towards Deneb by about the 91st century.{{fact|date=January 2025}}

The celestial pole was close to Thuban around 2750 BCE, and during classical antiquity it was slightly closer to Kochab (β UMi) than to Polaris, although still about {{val|10|ul=°}} from either star.{{cite web | first=Ian | last=Ridpath | url=http://www.ianridpath.com/startales/ursaminor.html#polaris | work=Star Tales | title=Ursa Minor, the Little Bear | date=2018 | access-date=20 August 2016 }} It was about the same angular distance from β UMi as to α UMi by the end of late antiquity. The Greek navigator Pytheas in ca. 320 BC described the celestial pole as devoid of stars. However, as one of the brighter stars close to the celestial pole, Polaris was used for navigation at least from late antiquity, and described as ἀεί φανής (aei phanēs) "always visible" by Stobaeus (5th century), also termed Λύχνος (Lychnos) akin to a burner or lamp and would reasonably be described as stella polaris from about the High Middle Ages and onwards, both in Greek and Latin. On his first trans-Atlantic voyage in 1492, Christopher Columbus had to correct for the "circle described by the pole star about the pole".{{cite book | title=The Life of the Admiral Christopher Columbus by His Son Fredinand | first=Ferdinand | last=Columbus | author-link=Ferdinand Columbus |translator-link=Benjamin Keen | translator1-first=Benjamin | translator1-last=Keen | publication-place=London | publisher=Folio Society | date=1960 | page=74 }} In Shakespeare's play Julius Caesar, written around 1599, Caesar describes himself as being "as constant as the northern star", although in Caesar's time there was no constant northern star. Despite its relative brightness, it is not, as is popularly believed, the brightest star in the sky.{{Cite news |last=Geary |first=Aidan |date=June 30, 2018 |title=Look up, be patient and 'think about how big the universe is': Expert tips for stargazing this summer |url=https://www.cbc.ca/news/canada/manitoba/stargazing-constellations-how-to-1.4726939 |access-date=June 29, 2024 |work=Canadian Broadcasting Corporation}}

Polaris was referenced in the classic Nathaniel Bowditch maritime navigation book American Practical Navigator (1802), where it is listed as one of the navigational stars.{{cite book | title=The American practical navigator : an epitome of navigation | first1=Nathaniel | last1=Bowditch | author2=National Imagery and Mapping Agency | publisher=Paradise Cay Publications | year=2002 | isbn=978-0-939837-54-0 | page=248 | chapter=15 | author1-link=Nathaniel Bowditch | chapter-url=https://books.google.com/books?id=pXjHDnIE_ygC&pg=PR1}}

Image:Polaris system.jpg

The modern name PolarisIAU Working Group on Star Names {{cite web | url=http://www.pas.rochester.edu/~emamajek/WGSN/IAU-CSN.txt | title=IAU Catalog of Star Names |access-date=2016-07-28 }} is shortened from the Neo-Latin stella polaris ("polar star"), coined in the Renaissance when the star had approached the celestial pole to within a few degrees.

Gemma Frisius, writing in 1547, referred to it as stella illa quae polaris dicitur ("that star which is called 'polar'"), placing it 3° 8' from the celestial pole.{{cite book | title=Gemmae Frisii de astrolabo catholico liber: quo latissime patentis instrumenti multiplex usus explicatur, & quicquid uspiam rerum mathematicarum tradi possit continetur | publisher=Steelsius | date=1556 | url=https://books.google.com/books?id=8XE6AAAAcAAJ&pg=PA20 | page=20 }}{{cite book |last1=Kunitzsch |first1=Paul |last2=Smart |first2=Tim |date = 2006 |title = A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations |edition = 2nd rev. |publisher = Sky Publishing |location = Cambridge, Massachusetts |isbn = 978-1-931559-44-7 |page = 23}}

In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN){{Cite web|url=https://www.iau.org/science/scientific_bodies/working_groups/280/|title=International Astronomical Union {{!}} IAU|website=www.iau.org|access-date=2019-01-19}} to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included Polaris for the star α Ursae Minoris Aa.{{Cite web|url=https://www.iau.org/static/science/scientific_bodies/working_groups/280/WGSN_bulletin1.pdf|title=Bulletin of the IAU Working Group on Star Names, No. 1}}

In antiquity, Polaris was not yet the closest naked-eye star to the celestial pole, and the entire constellation of Ursa Minor was used for navigation rather than any single star. Polaris moved close enough to the pole to be the closest naked-eye star, even though still at a distance of several degrees, in the early medieval period, and numerous names referring to this characteristic as polar star have been in use since the medieval period. In Old English, it was known as scip-steorra ("ship-star").{{citation needed|date=October 2023}}

In the "Old English rune poem", the T-rune is apparently associated with "a circumpolar constellation", or the planet Mars.{{cite book | first=Bruce | last=Dickins | title=Runic and heroic poems of the old Teutonic peoples | date=1915 | page=18 }}; Dickins' "a circumpolar constellation" is attributed to L. Botkine, La Chanson des Runes (1879).

In the Hindu Puranas, it became personified under the name Dhruva ("immovable, fixed").{{cite book | first=Alain | last=Daniélou | author-link=Alain Daniélou | url=https://books.google.com/books?id=1HMXN9h6WX0C&pg=PA186 | title=The Myths and Gods of India: The Classic Work on Hindu Polytheism | publisher=Princeton/Bollingen (1964); Inner Traditions/Bear & Co | date=1991 | isbn=978-0-892-813544 | page=186 }}

In the later medieval period, it became associated with the Marian title of Stella Maris "Star of the Sea" (so in Bartholomaeus Anglicus, c. 1270s),{{cite book | editor1-first=James Orchard | editor1-last=Halliwell-Phillipps | title=The Works of William Shakespeare | volume=5 | date=1856 | url=https://books.google.com/books?id=7NVfAAAAcAAJ&pg=PA40 | page=40 }} due to an earlier transcription error.{{Catholic Encyclopedia|prescript=|wstitle=The Name of Mary}}

An older English name, attested since the 14th century, is lodestar "guiding star", cognate with the Old Norse leiðarstjarna, Middle High German leitsterne.{{cite book | first1=Friedrich | last1=Kluge | first2=Alfred | last2=Götze | url=https://books.google.com/books?id=R1K9DwAAQBAJ&pg=PA355 | title=Etymologisches Wörterbuch der deutschen Sprache | publisher=Walter de Gruyter | date=1943 | isbn=978-3-111-67185-7 | page=355 }}

The ancient name of the constellation Ursa Minor, Cynosura (from the Greek {{lang|grc|κυνόσουρα}} "the dog's tail"),{{cite book | first=Ian | last=Ridpath | title=Star Tales | url=https://books.google.com/books?id=-dXYDwAAQBAJ | date=2018-06-28 | publisher=Lutterworth Press | isbn=978-0-7188-4782-1 }} became associated with the pole star in particular by the early modern period. An explicit identification of Mary as stella maris with the polar star (Stella Polaris), as well as the use of Cynosura as a name of the star, is evident in the title Cynosura seu Mariana Stella Polaris (i.e. "Cynosure, or the Marian Polar Star"), a collection of Marian poetry published by Nicolaus Lucensis (Niccolo Barsotti de Lucca) in 1655. {{citation needed|date=May 2018}}

File:Book of the Fixed Stars Auv0043 ursa minor cropped.jpg, Polaris named al-Judayy "الجدي" in the lower right.]]

Its name in traditional pre-Islamic Arab astronomy was al-Judayy الجدي ("the kid", in the sense of a juvenile goat ["le Chevreau"] in Description des Etoiles fixes),{{cite book

| author=ʻAbd al-Raḥmān ibn ʻUmar Ṣūfī

| title=Description des Etoiles fixes | page=45

| year=1874 | publisher=Commissionnaires de lÁcadémie Impériale des sciences

| url=https://books.google.com/books?id=nJRHAAAAYAAJ&pg=PA45

}} and that name was used in medieval Islamic astronomy as well.

{{cite web

|last=Al-Sufi

|first=AbdulRahman

|date = 964

|title = Book Of Fixed Stars

|url = http://gallica.bnf.fr/ark:/12148/btv1b60006156/f48.item

}}

{{Cite book

|last=Schjellerup

|first=Hans

|date = 1874

|title = Description des Etoiles fixes

|page = 45

|url = https://books.google.com/books?id=nJRHAAAAYAAJ&pg=PA45

}} In those times, it was not yet as close to the north celestial pole as it is now, and used to rotate around the pole.{{fact|date=January 2025}}

It was invoked as a symbol of steadfastness in poetry, as "steadfast star" by Spenser.

Shakespeare's sonnet 116 is an example of the symbolism of the north star as a guiding principle: "[Love] is the star to every wandering bark / Whose worth's unknown, although his height be taken."{{fact|date=January 2025}}

In Julius Caesar, Shakespeare has Caesar explain his refusal to grant a pardon: "I am as constant as the northern star/Of whose true-fixed and resting quality/There is no fellow in the firmament./The skies are painted with unnumbered sparks,/They are all fire and every one doth shine,/But there's but one in all doth hold his place;/So in the world" (III, i, 65–71). Of course, Polaris will not "constantly" remain as the north star due to precession, but this is only noticeable over centuries.{{citation needed|date=May 2018}}

In Inuit astronomy, Polaris is known as Nuutuittuq (syllabics: {{lang|iu-Cans|ᓅᑐᐃᑦᑐᖅ}}).{{Cite book|last=Penprase|first=Bryan E.|title=The Power of Stars|publisher=Springer|year=2011|isbn=978-1-4419-6802-9|location=New York, NY|page=45|chapter=Northern Circumpolar Sky from Around the World: The Arctic Inuit Sky}}

In traditional Lakota star knowledge, Polaris is named "Wičháȟpi Owáŋžila". This translates to "The Star that Sits Still". This name comes from a Lakota story in which he married Tȟapȟúŋ Šá Wíŋ, "Red Cheeked Woman". However, she fell from the heavens, and in his grief Wičháȟpi Owáŋžila stared down from "waŋkátu" (the above land) forever.{{Cite web |url=https://lastrealindians.com/news/2019/12/26/winter-solstice-is-sacred-time-a-time-to-carry-one-another-by-dakota-wind |title=Winter Solstice is Sacred Time a Time to Carry One Another by Dakota Wind |date=2019-12-27 |first=Dakota |last=Wind |work=Last Real Indians }}

The Plains Cree call the star in Nehiyawewin: acâhkos êkâ kâ-âhcît "the star that does not move" (syllabics: {{lang|crk|ᐊᒑᐦᑯᐢ ᐁᑳ ᑳ ᐋᐦᒌᐟ}}).{{cite web |title=Polaris |url=https://dictionary.plainscree.atlas-ling.ca/ |website=Plains Cree Dictionary |access-date=13 December 2022}}

In Mi'kmawi'simk the star is named Tatapn.{{cite news |last1=Lebans |first1=Jim |title=Mi'kmaw astronomer says we should acknowledge we live under Indigenous skies |url=https://www.cbc.ca/radio/quirks/oct-1-redirecting-an-asteroid-rainforest-politics-wildlife-and-covid-and-more-1.6599378/mi-kmaw-astronomer-says-we-should-acknowledge-we-live-under-indigenous-skies-1.6600279 |access-date=2022-12-21 |agency=Canadian Broadcasting Corporation |date=2022-09-29 }}

In the ancient Finnish worldview, the North Star has also been called taivaannapa and naulatähti ("the nailstar") because it seems to be attached to the firmament or even to act as a fastener for the sky when other stars orbit it. Since the starry sky seemed to rotate around it, the firmament is thought of as a wheel, with the star as the pivot on its axis. The names derived from it were sky pin and world pin.{{citation needed|date=June 2023}}

Image:Stellarparallax parsec1.svg, which is the distance from the Sun to an astronomical object which has a parallax angle of one arcsecond. (1 AU and 1 pc are not to scale, 1 pc = about 206265 AU)]]

Many recent papers calculate the distance to Polaris at about 433 light-years (133 parsecs), based on parallax measurements from the Hipparcos astrometry satellite. Older distance estimates were often slightly less, and research based on high resolution spectral analysis suggests it may be up to 110 light years closer (323 ly/99 pc).{{cite journal|bibcode=2013ApJ...762L...8T|title=The Pulsation Mode of the Cepheid Polaris|journal=The Astrophysical Journal Letters|volume=762|issue=1|pages=L8|last1=Turner|first1=D. G.|last2=Kovtyukh|first2=V. V.|last3=Usenko|first3=I. A.|last4=Gorlova|first4=N. I.|date=2013|doi=10.1088/2041-8205/762/1/L8|arxiv = 1211.6103 |s2cid=119245441}} Polaris is the closest Cepheid variable to Earth so its physical parameters are of critical importance to the whole astronomical distance scale. It is also the only one with a dynamically measured mass.

The Hipparcos spacecraft used stellar parallax to take measurements from 1989 and 1993 with the accuracy of 0.97 milliarcseconds (970 microarcseconds), and it obtained accurate measurements for stellar distances up to 1,000 pc away.{{Cite journal | doi = 10.1023/A:1005081918325| year = 1997| last1 = Van Leeuwen | first1 = F. | journal = Space Science Reviews| volume = 81| issue = 3/4| pages = 201–409| title = The Hipparcos Mission|bibcode = 1997SSRv...81..201V | s2cid = 189785021}} The Hipparcos data was examined again with more advanced error correction and statistical techniques.{{Cite journal | last1 = Van Leeuwen | first1 = F. | title = Validation of the new Hipparcos reduction | doi = 10.1051/0004-6361:20078357 | journal = Astronomy and Astrophysics | volume = 474 | issue = 2 | pages = 653–664 | year = 2007 |arxiv = 0708.1752 |bibcode = 2007A&A...474..653V | s2cid = 18759600 }} Despite the advantages of Hipparcos astrometry, the uncertainty in its Polaris data has been pointed out and some researchers have questioned the accuracy of Hipparcos when measuring binary Cepheids like Polaris. The Hipparcos reduction specifically for Polaris has been re-examined and reaffirmed but there is still not widespread agreement about the distance.{{cite journal|bibcode=2013A&A...550L...3V|title=The HIPPARCOS parallax for Polaris|journal=Astronomy & Astrophysics|volume=550|pages=L3|last1=Van Leeuwen|first1=F.|date=2013|doi=10.1051/0004-6361/201220871|arxiv = 1301.0890 |s2cid=119284268}}

The next major step in high precision parallax measurements comes from Gaia, a space astrometry mission launched in 2013 and intended to measure stellar parallax to within 25 microarcseconds (μas).{{cite journal|bibcode=2012MNRAS.426.2463L|title=The expected performance of stellar parametrization with Gaia spectrophotometry|journal=Monthly Notices of the Royal Astronomical Society|volume=426|issue=3|pages=2463|last1=Liu|first1=C.|display-authors=4|last2=Bailer-Jones|first2=C. A. L.|last3=Sordo|first3=R.|last4=Vallenari|first4=A.|last5=Borrachero|first5=R.|last6=Luri|first6=X.|last7=Sartoretti|first7=P.|date=2012|doi=10.1111/j.1365-2966.2012.21797.x|doi-access=free |arxiv = 1207.6005 |s2cid=1841271}} Although it was originally planned to limit Gaia's observations to stars fainter than magnitude 5.7, tests carried out during the commissioning phase indicated that Gaia could autonomously identify stars as bright as magnitude 3. When Gaia entered regular scientific operations in July 2014, it was configured to routinely process stars in the magnitude range 3 – 20.{{cite journal |bibcode=2014SPIE.9143E..0YM |title=Enabling Gaia observations of naked-eye stars |last1=Martín-Fleitas |first1=J. |last2=Sahlmann |first2=J. |last3=Mora |first3=A. |last4=Kohley |first4=R. |last5=Massart |first5=B. |last6=l'Hermitte |first6=J. |last7=Le Roy |first7=M. |last8=Paulet |first8=P. |editor-first1=Jacobus M |editor-first2=Mark |editor-first3=Giovanni G |editor-first4=Howard A |editor-last1=Oschmann |editor-last2=Clampin |editor-last3=Fazio |editor-last4=MacEwen |journal=Space Telescopes and Instrumentation 2014: Optical |series=Space Telescopes and Instrumentation 2014: Optical, Infrared, and Millimeter Wave |year=2014 |volume=9143 |pages=91430Y |doi=10.1117/12.2056325 |arxiv=1408.3039 |s2cid=119112009 }} Beyond that limit, special procedures are used to download raw scanning data for the remaining 230 stars brighter than magnitude 3; methods to reduce and analyse these data are being developed; and it is expected that there will be "complete sky coverage at the bright end" with standard errors of "a few dozen μas".{{ Citation | author = T. Prusti | collaboration = GAIA Collaboration | date = 2016 | title = The Gaia mission | type = forthcoming article | journal = Astronomy and Astrophysics | volume = 595 | pages = A1 | doi = 10.1051/0004-6361/201629272 | arxiv = 1609.04153 | bibcode = 2016A&A...595A...1G | s2cid = 9271090 }} Gaia Data Release 2 does not include a parallax for Polaris, but a distance inferred from it is {{val|136.6|0.5|ul=pc}} (445.5 ly) for Polaris B,{{cite journal|bibcode=2018AJ....156...58B|title=Estimating Distance from Parallaxes. IV. Distances to 1.33 Billion Stars in Gaia Data Release 2|journal=The Astronomical Journal|volume=156|issue=2|pages=58|last1=Bailer-Jones|first1=C. A. L|last2=Rybizki|first2=J|last3=Fouesneau|first3=M|last4=Mantelet|first4=G|last5=Andrae|first5=R|year=2018|doi=10.3847/1538-3881/aacb21|arxiv=1804.10121|s2cid=119289017 |doi-access=free }} somewhat further than most previous estimates and several times more accurate. This was further improved to {{val|137.2|0.3|ul=pc}} (447.6 ly), upon publication of the Gaia Data Release 3 catalog on 13 June 2022 which superseded Gaia Data Release 2.{{cite Gaia DR3|576402619921510144}}

Polaris is depicted in the flag and coat of arms of the Canadian Inuit territory of Nunavut,{{cite web | website=Legislative Assembly of Nunavut | title=The Coat of Arms of Nunavut. (n.d.) | url=https://assembly.nu.ca/about-legislative-assembly/coat-arms-nunavut | access-date=2021-09-15 }} the flag of the U.S. states of Alaska and Minnesota,{{cite web | last=Swanson | first=Stephen | title=YouTuber's critique of Minnesota state flag finalists draws 1 million views | website=CBS Minnesota | date=2023-12-15 | url=https://www.cbsnews.com/minnesota/news/minnesota-state-flag-finalists-cgp-grey-youtube/ | access-date=2024-08-28}} and the flag of the U.S. city of Duluth, Minnesota.{{cite news |url= https://www.fox21online.com/2019/08/14/duluth-picks-new-city-flag/ |title= Duluth Picks New City Flag |publisher= Fox 21 |date=2019-08-14 |accessdate = 2024-09-03}}{{cite web |url=https://duluthmn.gov/media/13186/duluth-flag-press-release.pdf |title= City of Duluth selects new flag |first= Kate |last= Van Daele |publisher = City of Duluth |date= 2019-08-14 |accessdate= 2024-09-05}}

Flag of Nunavut.svg|Flag of Nunavut

Flag of Alaska.svg|Flag of Alaska

Flag of Minnesota.svg|Flag of Minnesota

Flag of Duluth, Minnesota.svg|Flag of Duluth, Minnesota

Flag of Maine.svg|Flag of Maine

Flag of Maine (1901–1909).svg|Flag of Maine (1901–1909)

Pan American Exposition Flag.svg|Flag of the Pan-American Exposition (1901){{cite web |url=https://panam1901.org/documents/flag/pan_american_flag.html |title=Pan-American Flag |work=panam1901.org |access-date=16 November 2024}}

Francis Leopold McClintock's sledge flag (1852–1854).svg|Sledge flag used by Francis Leopold McClintock in the Arctic (1852–1854){{cite web |url=https://www.arcticfoxtrail.com/gallery.shtml |title=Sir Francis McClintock Explorer - Arctic Fox Exhibition, Louth County Museum (Gallery Section) |author= |date= |work=arcticfoxtrail.com |access-date=14 January 2025}}

Coat of arms of Nunavut.svg|Coat of arms of Nunavut

Seal of Minnesota.svg|Seal of Minnesota

Seal of Maine.svg|Seal of Maine

Utsjoki.vaakuna.svg|Coat of arms of Utsjoki{{citation needed|date=August 2022}}

UrsaMinorCC.jpg|Polaris is the brightest star in the constellation of Ursa Minor (upper right).

Ursa Major - Ursa Minor - Polaris.jpg|Big Dipper and Ursa Minor in relation to Polaris

Polaris star and companion.jpg|A view of Polaris in a small telescope. Polaris B is separated by 18 arc seconds from the primary star, Polaris A.

File:Polaris time-lapse illustrating Cepheid type variability.gif|A 4-day time lapse of Polaris illustrating its Cepheid type variability.

• The Chinese spy ship Beijixing is named after Polaris.
• USS Polaris is named after Polaris

• Extraterrestrial sky (for the pole stars of other celestial bodies)
• List of nearest supergiants
• Polar alignment
• Sigma Octantis
• Polaris Flare
• Regiment of the North Pole

{{Reflist|30em}}

{{Commons category|Polaris}}

{{Sky|02|31|48.7|+|89|15|51|430}}

{{s-start}}

{{s-bef

| before = Kochab & Pherkad

}}

{{s-ttl

| title = Pole star

| years = 500–3000

}}

{{s-aft

| after = Gamma Cephei

}}

{{s-end}}

{{Pole star}}

{{Stars of Ursa Minor|state=collapsed}}

{{Portal bar|Astronomy|Stars|Outer space}}

{{Authority control}}

Category:F-type supergiants

Category:F-type main-sequence stars

Category:Ursa Minor

Ursae Minoris, Alpha

Category:Durchmusterung objects

Ursae Minoris, 01

008890

011767

0424

Category:Stars with proper names

Category:Northern pole stars

Category:Classical Cepheid variables

Category:Suspected variables

Category:Triple star systems