9 Equulei

{{Starbox begin

|name = 9 Equulei

}}

{{Starbox observe

|epoch = J2000

|ra = {{RA|21|21|04.825}}

|dec = {{DEC|07|21|16.21}}

|appmag_v = 5.798

|constell = Equuleus

}}

{{Starbox character

|class = M2IIIa

|b-v = +1.66

|u-b = +1.97

|variable = suspected

}}

{{Starbox astrometry

|radial_v = {{val|-21.82|0.30}}

|prop_mo_ra = {{val|43.871|0.274}}

|prop_mo_dec = {{val|-17.822|0.261}}

|parallax = 4.3895

|p_error = 0.1647

|parallax_footnote=

|dist_ly =

|dist_pc =

|absmag_v = −0.69

}}

{{Starbox detail

|mass =

|radius = 58

|luminosity = 720

|temperature = 3,920

|metal_fe =

|gravity =

|rotational_velocity=

|age_byr =

}}

{{Starbox catalog

|names = HIP 105413, HD 203291, HR 8163, SAO 126719

}}

9 Equulei is an M-type star in the constellation Equuleus. It is an asymptotic giant branch (AGB) star, a star that has exhausted its core helium and is now fusing both hydrogen and helium in shells outside the core. It is also a suspected variable star with an amplitude of about 0.05 magnitudes.

The spectral type is M2IIIa, meaning it is a relatively cool giant star. As an AGB star, it is burning hydrogen and helium in shells around an inert carbon-oxygen core. It has expanded to 58 times the radius of the Sun, and it radiates 720 times as much electromagnetic radiation from a photosphere with an effective temperature of {{val|3,920|fmt=commas|ul=K}}.

References

{{Reflist|refs=

{{cite journal|bibcode=2000A&A...355L..27H|title=The Tycho-2 catalogue of the 2.5 million brightest stars|journal=Astronomy and Astrophysics|volume=355|pages=L27|last1=Høg|first1=E.|last2=Fabricius|first2=C.|last3=Makarov|first3=V. V.|last4=Urban|first4=S.|last5=Corbin|first5=T.|last6=Wycoff|first6=G.|last7=Bastian|first7=U.|last8=Schwekendiek|first8=P.|last9=Wicenec|first9=A.|year=2000}}

{{cite journal|bibcode=1967PDAO...13...47Y|title=MK Spectral Types of Bright M-Type Stars|journal=Publications of the Dominion Astrophysical Observatory Victoria|volume=13|pages=47|last1=Yamashita|first1=Y.|year=1967}}

{{cite journal|bibcode=1991bsc..book.....H|title=The Bright star catalogue|journal=New Haven, Conn.: Yale University Observatory, 5th Rev.ed.|year=1991|last1=Hoffleit|first1=Dorrit|last2=Jaschek|first2=Carlos}}

{{cite journal|bibcode=2009yCat....102025S|title=VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)|journal=VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S|volume=1|pages=B/gcvs|display-authors=etal|last1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}

{{cite journal|bibcode=1992AJ....104..275E|title=Asymptotic Giant Branch Stars Near the Sun|journal=The Astronomical Journal|volume=104|pages=275|last1=Eggen|first1=Olin J.|year=1992|doi=10.1086/116239}}

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

}}

Category:Equuleus

Category:M-type giants

Category:Durchmusterung objects

Category:Suspected variables