Alpha Piscium

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Binary star system in the constellation Pisces

title: "Alpha Piscium" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["am-stars", "alpha2-canum-venaticorum-variables", "double-stars", "pisces-(constellation)", "stars-with-proper-names", "bayer-objects", "durchmusterung-objects", "flamsteed-objects", "henry-draper-catalogue-objects", "hipparcos-objects", "bright-star-catalogue-objects"] description: "Binary star system in the constellation Pisces" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/Alpha_Piscium" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Binary star system in the constellation Pisces ::

| name = α Piscium | image = | image=Pisces IAU.svg | alt= | float=center | width=250 | label= | position=right | mark=Red circle.svg | mark_width=10 | mark_link=α Psc | x=228 | y=525 | caption=Location of α Piscium (circled) | epoch = J2000.0 | equinox = J2000.0 (ICRS) | constell = Pisces | ra = | dec = | appmag_v = 3.82 (4.33 + 5.23) | class = kA0hA7 Sr + kA2hF2mF2 (IV) | b-v = | u-b = | variable = α2 CVn | radial_v = | prop_mo_ra = +32.45 | prop_mo_dec = +0.04 | parallax = 21.66 | p_error = 1.06 | parallax_footnote = | absmag_v = +0.50 | reference = | period = 3267.4 | axis = 7.4 | eccentricity = 0.465 | inclination = 113.4 | node = 3.70 | periastron = 2188.6 | periarg = 147.9 | source = | component1 = α Psc A | mass = | radius = 2.45 | luminosity = | gravity = 3.85 | temperature = | metal_fe = | rotational_velocity = 81 | age_myr = | component2 = α Psc B | mass2 = | temperature2 = | radius2 = | luminosity2 = | gravity2 = | age_myr2 = | rotational_velocity2 = 84 | names = | component1 = α Psc A | names1 = | component2 = α Psc B | names2 = | Simbad = alf+Psc | sn=α Psc | Simbad2 = alf+Psc+A | sn2=α Psc A | Simbad3 = alf+Psc+B | sn3=α Psc B

Alpha Piscium (α Piscium) is a binary star system in the equatorial constellation of Pisces. Based upon parallax measurements made by the Hipparcos spacecraft, it is about from the Solar System.

The two components are designated Alpha Piscium A (officially named Alrescha , the traditional name of the system){{cite book |last1=Kunitzsch |first1=Paul |last2=Smart |first2=Tim |date = 2006 |edition = 2nd rev. |title = A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations |publisher = Sky Pub |location = Cambridge, Massachusetts |isbn = 978-1-931559-44-7

Nomenclature

α Piscium (Latinised to Alpha Piscium) is the star's Bayer designation. The designations of the two components as Alpha Piscium A and B derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).

The system bore the traditional name Alrescha (alternatively Al Rescha, Alrischa, Alrisha) derived from the Arabic الرشآء ar-Rishā’ "the cord" and less commonly Kaitain and Okda, the latter from the Arabic عقدة ʽuqdah "knot" (see Ukdah. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN approved the name Alrescha for the component Alpha Piscium A on 21 August 2016 and it is now so included in the List of IAU-approved Star Names.

In Chinese, 外屏 (Wài Píng), meaning Outer Fence, refers to an asterism consisting of Alpha Piscium, Delta Piscium, Epsilon Piscium, Zeta Piscium, Mu Piscium, Nu Piscium and Xi Piscium. Consequently, the Chinese name for Alpha Piscium itself is 外屏七 (Wài Píng qī, ).

Properties

Alpha Piscium comprises a close binary with angular separation of presently 1.8" between the components. The main star or primary (Alpha Piscium A) is of magnitude +4.33 and spectral type A0p, while the companion or secondary (Alpha Piscium B) is magnitude 5.23 and belongs to spectral class A3m. The two stars take more than 3,000 years to orbit one another and they will make their closest approach to each other around 2060. One or both of the stars may be a spectroscopic binary as well. The stars have masses of 2.55 and 2.64 solar masses respectively and shine with a total luminosity of 55 and 63 times that of the Sun.

::figure[src="https://upload.wikimedia.org/wikipedia/commons/c/c0/AlphaPscLightCurve.png" caption="TESS]]'' data"] ::

Alpha Piscium is catalogued as an α2 Canum Venaticorum variable, a type of variable star where the brightness changes are caused by the rotation of the star. The brightness varies by about 1/100 of a magnitude, identified from Hipparcos photometry. The primary component is thought to be the source of the variations, and it has a period of 0.845 days which corresponds to the rotation period of the star. Variations with a period of 6.65 days have also been identified in the variations.

Long-exposure observation

Stars that can set (not in a circumpolar constellation for the viewer) culminate at midnight – where viewed away from any polar region experiencing midnight sun – when at opposition, meaning they can be viewed from dusk until dawn. This applies to α Piscium on 21 October, in the current astronomical epoch.Ephemera table, rising and setting times In-the-Sky.org. Dominic C. Ford, 2011–2020; Cambridge UK.

Half of the year from this date, 22 April, the star will be at conjunction above or below, the sun – apart by the star's declination (angle set out in table, right). The nearby days and months have most of the star's risen time during daylight.

References

| 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}}

| title=Validation of the new Hipparcos reduction | last1=van Leeuwen | first1=F. | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | date=2007 | arxiv=0708.1752 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 | s2cid=18759600 | postscript=. }}

| title=XHIP: An extended hipparcos compilation | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | journal=Astronomy Letters | volume=38 | issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015 | arxiv=1108.4971 | s2cid=119257644 | postscript=. }}

| display-authors=1 | last1=Royer | first1=F. | last2=Grenier | first2=S. | last3=Baylac | first3=M.-O. | last4=Gómez | first4=A. E. | last5=Zorec | first5=J. | title=Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i | journal=Astronomy and Astrophysics | volume=393 | pages=897–911 | date=October 2002 | doi=10.1051/0004-6361:20020943 | bibcode=2002A&A...393..897R | arxiv=astro-ph/0205255 | s2cid=14070763 | postscript=. }}

| title=The Late A-Type Stars: Refined MK Classification, Confrontation with Stroemgren Photometry, and the Effects of Rotation | last1=Gray | first1=R. O. | last2=Garrison | first2=R. F. | journal=Astrophysical Journal Supplement | volume=70 | page=623 | date=July 1989 | postscript=. | doi=10.1086/191349 | bibcode=1989ApJS...70..623G | doi-access=free }}

| url=https://www.iau.org/public/themes/naming_stars/ | title=Naming Stars |publisher=IAU.org |access-date=2 March 2018}}

| url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=Division C WG Star Names | publisher=IAU Working Group on Star Names (WGSN) | access-date=22 May 2016 | postscript=. }}

| last1=Cowley | first1=A. | last2=Cowley | first2=C. | last3=Jaschek | first3=M. | last4=Jaschek | first4=C. | title=A study of the bright A stars. I. A catalogue of spectral classifications | journal=Astronomical Journal | postscript=. | volume=74 | pages=375–406 | date=April 1969 | doi=10.1086/110819 | bibcode=1969AJ.....74..375C }}

| first1=Richard Hinckley | last1=Allen | title=Star-names and their meanings | postscript=. | publisher=G. E. Stechert | year=1899 | pages=342−343 | url=https://books.google.com/books?id=5xQuAAAAIAAJ&pg=PA342 }} | first1=James B. | last1=Kaler | title=ALRESCHA (Alpha Piscium) | work=Stars | publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/alrescha.html | access-date=2012-04-06 | postscript=. }}

| title=alf Psc | access-date=2017-08-04 | postscript=. | mode=cs2 }}

| title=alf Psc A | access-date=2017-08-04 | postscript=. | mode=cs2 }}

| title=alf Psc B | access-date=2017-08-04 | postscript=. | mode=cs2 }}

References

  1. Peterson, Hannah Mary Bouvier. (1856). "Familiar Astronomy, Or, An Introduction to the Study of the Heavens". Princeton University.
  2. (2010). "On the naming convention used for multiple star systems and extrasolar planets".
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  4. (June 30, 2006). "Sixth Catalog of Orbits of Visual Binary Stars". [[United States Naval Observatory]].
  5. (2019). "A volume-limited survey of MCP stars within 100 pc - I. Fundamental parameters and chemical abundances". Monthly Notices of the Royal Astronomical Society.
  6. (2019). "On Properties of Main Sequence Magnetic Stars". Astrophysical Bulletin.
  7. (2017). "An investigation of the rotational properties of magnetic chemically peculiar stars". Monthly Notices of the Royal Astronomical Society.
  8. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S.
  9. (2012). "A photometric study of chemically peculiar stars with the STEREO satellites - I. Magnetic chemically peculiar stars". Monthly Notices of the Royal Astronomical Society.

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am-starsalpha2-canum-venaticorum-variablesdouble-starspisces-(constellation)stars-with-proper-namesbayer-objectsdurchmusterung-objectsflamsteed-objectshenry-draper-catalogue-objectshipparcos-objectsbright-star-catalogue-objects