Pi Puppis

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Second-brightest star in the constellation of Puppis

title: "Pi Puppis" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["puppis", "bayer-objects", "k-type-supergiants", "stars-with-proper-names", "hipparcos-objects", "bright-star-catalogue-objects", "henry-draper-catalogue-objects", "durchmusterung-objects", "binary-stars"] description: "Second-brightest star in the constellation of Puppis" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/Pi_Puppis" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Second-brightest star in the constellation of Puppis ::

| name = π Puppis | image= |image=Puppis constellation map.svg|alt=|float=center|width=240 |label=|position=right |mark=Red circle.svg|mark_width=12|mark_link=π Puppis |x=602|y=838 |caption=Location of π Puppis (circled) | epoch = J2000 | ra = | dec = | appmag_v = 2.692.76 | constell = Puppis | class = K3 Ib | b-v = +1.608 | u-b = +1.238 | variable = SRd | radial_v = +15.8 | prop_mo_ra = −10.05 | prop_mo_dec = +6.47 | parallax = 4.04 | p_error = 0.33 | parallax_footnote = | absmag_v = −4.5 | mass = | radius = 235 | luminosity = 11,378 | temperature = 3,990–4,055 | metal_fe = | gravity = 0.13 | rotational_velocity = | age_myr = | names= | Simbad = pi+Pup Pi Puppis, Latinized from π Puppis, also named Ahadi, is the second-brightest star in the southern constellation of Puppis. It has an apparent visual magnitude of about 2.7, so it can be viewed with the naked eye at night. Parallax measurements yield an estimated distance of roughly 810 ly from the Earth. This is a double star with a magnitude 6.86 companion at an angular separation of 0.72 arcsecond and a position angle of 148° from the brighter primary.

Description

::figure[src="https://upload.wikimedia.org/wikipedia/commons/8/8f/PiPupLightCurve.png" caption="A [[light curve]] for Pi Puppis, plotted from ''[[Hipparcos]]'' data, folded with the period derived by Koen and Eyer (2002)"] ::

The spectrum of Pi Puppis matches a stellar classification of K3 Ib. The Ib luminosity class indicates this a lower luminosity supergiant star that has consumed the hydrogen fuel at its core, evolved away from the main sequence, and expanded to about 235 times the Sun's radius. The effective temperature of the star's outer envelope is approximately , which gives it the orange hue of a K-type star. With a mass 11.7 times that of the Sun, this is a short-lived star with an estimated age of 20 million years.

It is a semiregular variable star that varies in apparent magnitude from a high of 2.70 down to 2.85. Pi Puppis is the brightest star in the open cluster Collinder 135.

Nomenclature

This star does not seem to have had a traditional proper name, but some 21st-century sources use the name Ahadi, which is derived from Arabic for "having much promise". This name appears in the SIMBAD database and at least one academic paper.

In Chinese, 弧矢 (Hú Shǐ), meaning Bow and Arrow, refers to an asterism consisting of π Puppis, δ Canis Majoris, η Canis Majoris, HD 63032, HD 65456, ο Puppis, k Puppis, ε Canis Majoris and κ Canis Majoris. Consequently, π Puppis itself is known as 弧矢九 (Hú Shǐ jiǔ, ).

Observation

::figure[src="https://upload.wikimedia.org/wikipedia/commons/8/8e/Cr135Stellarium.png" caption="[[Collinder 135"] ::

Pi Puppis is a semiregular variable star with an apparent magnitude of 2.733. It appears slightly orange in color with a B-V color index of +1.608, similar to that of the famous Mira. It is typically the second brightest star in Puppis, only behind the blue supergiant Naos, and the brightest star in the open cluster Collinder 135.

About every five years, the Pi Puppids, a meteor shower associated with the comet 26P/Grigg–Skjellerup, appears near the star in late April. The Pi Puppids are a variable meteor shower, with varying maximums each year.

References

References

  1. (15 June 2017). "Fundamental parameters and infrared excesses of Tycho–Gaia stars". Monthly Notices of the Royal Astronomical Society.
  2. {{in lang. zh [http://aeea.nmns.edu.tw/2006/0607/ap060716.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 16 日] {{Webarchive. link. (2011-08-22)
  3. (March 2023). ["Night Sky: A Field Guide to the Constellations"](https://books.google.com/books?id=LbAbDQAAQBAJ&pg=PA264 }}{{Dead link). Adventure Publications.
  4. van Leeuwen, F.. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics.
  5. (1979). "Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars". Dept. of Astronomy, University of Michigan.
  6. (June 20–24, 1966). "Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30". [[International Astronomical Union]].
  7. (1966). "A System of photometric standards". Publicaciones Universidad de Chile, Department de Astronomy.
  8. (February 1983). "Six clusters in Puppis-Vela". Astronomical Journal.
  9. "CCDM J07171-3706A -- Double or multiple star". Centre de Données astronomiques de Strasbourg.
  10. (June 2011). "The basal chromospheric Mg II h+k flux of evolved stars: probing the energy dissipation of giant chromospheres". Monthly Notices of the Royal Astronomical Society.
  11. (1978). "Burnham's celestial handbook: an observer's guide to the universe beyond the solar system". Courier Dover Publications.
  12. (January 2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society.
  13. (April 2000). "Two-colour photometry for 9473 components of close Hipparcos double and multiple stars". Astronomy and Astrophysics.
  14. (January 1999). "The 74th Special Name-list of Variable Stars". Information Bulletin on Variable Stars.
  15. (December 21, 2004). "The Colour of Stars". Commonwealth Scientific and Industrial Research Organisation.
  16. (2001). "A Large Spectral Class Dependence of the Wilson-Bappu Effect among Luminous Stars". The Publications of the Astronomical Society of the Pacific.
  17. 弧矢 (Hú Shǐ) is westernized into '''Koo She'''. R.H. Allen had opinion that ''Koo She'' refers to the asterism including δ Velorum and ω Velorum. AEEA opinion is, δ Velorum is member of {{lang. zh. 天社 ({{lang. zh-Latn. Tiān Shè), meaning ''[[Well (Chinese constellation). Celestial Earth God's Temple]]'' asterism and ω Velorum is not member of any asterisms. 天社 (Tiān Shè)is westernized into '''Tseen She''' and R.H.Allen used the term ''Tseen She'' for Chinese name of [[Eta Carinae. η Carinae]]. See [https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Argo_Navis*.html Richard Hinckley Allen: Star Names — Their Lore and Meaning: Argo Navis] and {{in lang. zh [http://aeea.nmns.edu.tw/2006/0607/ap060717.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 17 日] {{Webarchive. link. (2012-02-04 .)
  18. Celis S., L.. (1982). "Red variable stars. I — UBVRI photometry and photometric properties". Astronomical Journal.
  19. "zeta Pup". [[AAVSO]].
  20. "Meteor Data Center: 137 PPU". [[International Astronomical Union]] (IAU).
  21. Kaler, Jim. "Pi Pup".
  22. (October 2022). "Colour evolution of Betelgeuse and Antares over two millennia, derived from historical records, as a new constraint on mass and age". [[Monthly Notices of the Royal Astronomical Society]].

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puppisbayer-objectsk-type-supergiantsstars-with-proper-nameshipparcos-objectsbright-star-catalogue-objectshenry-draper-catalogue-objectsdurchmusterung-objectsbinary-stars