Delta Indi
Star in the constellation Indus
title: "Delta Indi" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["f-type-subgiants", "binary-stars", "indus-(constellation)", "bayer-objects", "durchmusterung-objects", "henry-draper-catalogue-objects", "hipparcos-objects", "bright-star-catalogue-objects"] description: "Star in the constellation Indus" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/Delta_Indi" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Star in the constellation Indus ::
| image = |image=Indus constellation map.svg|alt=|float=center|width=250 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=δ Indi |x=335|y=530 | caption = Location of δ Indi (circled in red) | epoch = J2000.0 | equinox = J2000.0 (ICRS) | constell = Indus | ra = | dec = | appmag_v = +4.40 (4.80 + 5.96) | class = F0 IV | b-v = +0.28 | u-b = +0.10 | variable = | radial_v = | prop_mo_ra = +41.94 | prop_mo_dec = −3.93 | parallax = 17.34 | p_error = 0.48 | parallax_footnote = | absmag_v = +0.60 | reference = | period = | axis = | eccentricity = | inclination = | node = | periastron = | periarg = | source = | component1 = δ Ind A | mass = | radius = | luminosity = 48 | temperature = | gravity = 3.85 | metal_fe = −0.21 | rotational_velocity = 130 | age_myr = 462 | component2 = δ Ind B | mass2 = | names = | Simbad = del+Ind
Delta Indi, Latinized from δ Indi, is a binary star system in the southern constellation of Indus. It is visible to the naked eye with a combined apparent visual magnitude of +4.40. The brighter primary, designated component A, is magnitude 4.80 while the companion, component B, is magnitude 5.96. Based upon an annual parallax shift of 17.34 mas as measured from Earth, the system is located about 188 light years from the Sun.
The binary nature of this system was discovered by South African astronomer William Stephen Finsen from 1936 onward, with his published orbital elements appearing in 1956. The pair have an orbital period of 12.2 years, a semimajor axis of 0.176 arc seconds, and an eccentricity of around 0.03. They have been listed with a stellar classification of F0 IV by multiple authors, suggesting they are yellow-white hued F-type subgiant stars. However, their estimated masses don't match this classification, so Docobo and Andrade (2013) suggest the Hipparcos parallax may have been underestimated. One paper has published separate spectral classes of A8(V) and F3(V) respectively for the two components.
References
| 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=. }}
| title=The Orbit of Phi 312 = Delta Indi | last1=Finsen | first1=W. S. | journal=Monthly Notes of the Astronomical Society of South Africa | volume=15 | page=49 | year=1956 | bibcode=1956MNSSA..15...49F | postscript=. }}
| last1=Nicolet | first1=B. | title=Photoelectric photometric Catalogue of homogeneous measurements in the UBV System | journal=Astronomy and Astrophysics Supplement Series | volume=34 | pages=1–49 | year=1978 | bibcode=1978A&AS...34....1N | postscript=. }}
| last1=van Belle | first1=Gerard T. | title=Interferometric observations of rapidly rotating stars | journal=The Astronomy and Astrophysics Review | volume=20 | issue=1 | article-number=51 |date=March 2012 | doi=10.1007/s00159-012-0051-2 | bibcode=2012A&ARv..20...51V | arxiv=1204.2572 | s2cid=119273474 | postscript=. }}
| last1=Malkov | first1=O. Yu. | last2=Tamazian | first2=V. S. | last3=Docobo | first3=J. A. | last4=Chulkov | first4=D. A. | title=Dynamical Masses of a Selected Sample of Orbital Binaries | journal=Astronomy & Astrophysics | postscript=. | volume=546 | id=A69 | pages=5 | date=2012 | doi=10.1051/0004-6361/201219774 | bibcode =2012A&A...546A..69M | doi-access=free }}
| title=The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets | last1=David | first1=Trevor J. | last2=Hillenbrand | first2=Lynne A. | journal=The Astrophysical Journal | volume=804 | issue=2 | pages=146 | year=2015 | bibcode=2015ApJ...804..146D | doi=10.1088/0004-637X/804/2/146 | arxiv=1501.03154 | s2cid=33401607 | postscript=. }}
| title=Dynamical and physical properties of 22 binaries discovered by W. S. Finsen | url=http://mnras.oxfordjournals.org/content/428/1/321.full | archive-url=https://archive.today/20141205013707/http://mnras.oxfordjournals.org/content/428/1/321.full | url-status=dead | archive-date=2014-12-05 | last1=Docobo | first1=J. A. | last2=Andrade | first2=M. | journal=Monthly Notices of the Royal Astronomical Society | volume=428 | issue=1 | pages=321–339 | year=2013 | postscript=. | bibcode=2013MNRAS.428..321D | doi=10.1093/mnras/sts045 | doi-access=free }}
| title=del Ind | accessdate=2017-08-18 | postscript=. }}
References
- (1980). "Scanner studies of composite spectra I. Dwarfs.". The Astrophysical Journal Supplement Series.
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