This star has been catalogued as aspectroscopic binary[11] and a companion was apparently detected through lunaroccultation.[12] However, the latter was pointed out as spurious.[7][13]Interferometric observations taken in 2017 finally revealed that Phi Sgr is indeed a binary. The companion is amain sequence star around 60% more massive than the Sun, with an orbital period of roughly a year and an orbital separation of1.31 AU.[6]
In the catalogue of stars in theCalendarium ofAl Achsasi al Mouakket, this star was designatedAoul al Sadirah, which was translated intoLatin asPrima τού al Sadirah, meaningfirst returning ostrich.[14]
This star, together withγ Sgr,δ Sgr,ε Sgr,ζ Sgr,λ Sgr,σ Sgr andτ Sgr comprising theTeapotasterism.[16] φ Sgr,σ Sgr,ζ Sgr,χ Sgr andτ Sgr wereAl Naʽām al Ṣādirah (النعم السادرة), the Returning Ostriches.[17] According to the catalogue of stars in theTechnical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars,Al Naʽām al Ṣādirah orNamalsadirah was originally the title for four stars: φ Sgr asNamalsadirah I,τ Sgr asNamalsadirah II,χ1 Sgr asNamalsadirah III andχ2 Sgr asNamalsadirah IV (exceptσ Sgr andζ Sgr) .[18]
^abcdWielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions",Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg,35 (35), Astronomisches Rechen-Institut Heidelberg: 1,Bibcode:1999VeARI..35....1W
^abHouk, Nancy (1979),Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 3, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan,Bibcode:1982mcts.book.....H
^abJohnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars",Communications of the Lunar and Planetary Laboratory,4 (99): 99,Bibcode:1966CoLPL...4...99J
^"phi Sgr -- Star",SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved2012-01-15
^"The Colour of Stars",Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived fromthe original on March 18, 2012, retrieved2012-01-16
