Alpha Indi

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Star in the constellation Indus

title: "Alpha Indi" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["bayer-objects", "henry-draper-catalogue-objects", "hipparcos-objects", "bright-star-catalogue-objects", "indus-(constellation)", "k-type-giants", "durchmusterung-objects", "horizontal-branch-stars", "lucidae"] description: "Star in the constellation Indus" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/Alpha_Indi" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Star in the constellation Indus ::

| name=α Indi | image= |image=Indus constellation map.svg|alt=|float=center|width=220 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=α Ind |x=844|y=256 |caption=Location of α Indi (circled) | epoch = J2000 | equinox = J2000 | constell = Indus | ra = | dec = | appmag_v = 3.11 | type = red clump | class = K0 III–IV | b-v = +1.00 | u-b = +0.79 | variable = | radial_v = −1.3 | prop_mo_ra = +50.922 | prop_mo_dec = +66.026 | pm_footnote = | parallax = 32.8989 | p_error = 0.2225 | parallax_footnote = | dist_footnote = | absmag_v = | source = | mass = | radius = | luminosity = | temperature = | gravity = | metal_fe = | age_gyr = | names=HD 196171, HR 7869, SAO 230300, FK5 769, CD−47°13477, HIP 101772 | Simbad=alf%20Ind

Alpha Indi (α Ind, α Indi) is the brightest star in the southern constellation Indus. Parallax measurements imply that it is located about 100 light years from Earth. It has an apparent visual magnitude of 3.22, being readily visible to the naked eye, and has an absolute magnitude of +0.78.

Characteristics

The stellar classification of Alpha Indi is K0 III-IV, meaning that it has exhausted the hydrogen at its core and evolved away from the main sequence, being now halfway between a subgiant and a giant star. It is estimated to be 1.6 billion years old, has 2.15 times the mass of the Sun, but has expanded to 9.9 times the radius of the Sun and irradiates 51 times its luminosity. The effective temperature of its photosphere is 4,900 K, giving it the characteristic orange hue of a K-type star. It may have two nearby M-type companion stars, which are located at least 2,000 AU from the primary.

Nomenclature

Alpha Indi is the star's Bayer designation. In China, this star is called Pe Sze where it also was known as the Persian, a title from the Jesuit missionaries. The term Pe Sze is from the name of asterism 波斯 (Bō Sī, ). In Chinese astronomy, consequently, α Indi itself is known as 波斯二 (Bō Sī èr, )

References

References

  1. {{Cite Gaia DR3. 6674382927491854848
  2. [https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Indus*.html Star Name - R.H.Allen p. 246]
  3. {{in lang. zh [http://aeea.nmns.edu.tw/2006/0607/ap060730.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 30 日] {{Webarchive. link. (2011-05-22 ))
  4. (2007). "The abundances of nearby red clump giants". Monthly Notices of the Royal Astronomical Society.
  5. (2022-01-01). "CORALIE radial-velocity search for companions around evolved stars (CASCADES). I. Sample definition and first results: Three new planets orbiting giant stars". Astronomy and Astrophysics.
  6. (July 2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I". The Astronomical Journal.
  7. (June 20–24, 1966). "Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30". [[International Astronomical Union]].
  8. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory.
  9. (2021-02-01). "Stellar chromospheric activity of 1674 FGK stars from the AMBRE-HARPS sample. I. A catalogue of homogeneous chromospheric activity". Astronomy and Astrophysics.
  10. "alf Ind -- Star in double system". [[Centre de Données astronomiques de Strasbourg]].
  11. "THE PERSIAN (Alpha Indi)". [[University of Illinois]].
  12. (December 21, 2004). "The Colour of Stars". [[Commonwealth Scientific and Industrial Research Organisation]].

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bayer-objectshenry-draper-catalogue-objectshipparcos-objectsbright-star-catalogue-objectsindus-(constellation)k-type-giantsdurchmusterung-objectshorizontal-branch-starslucidae