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Astrometric binary star in the constellation Sagittarius
Iota Sagittarii (Iota Sgr , ι Sagittarii , ι Sgr ) is a
star in the
zodiac
constellation of
Sagittarius . With an
apparent visual magnitude of +4.118, it is bright enough to be viewed with the naked eye.
[2] Based upon an annual
parallax shift of 17.94
mas as seen from Earth,
[1] this star is located 182
light years from the
Sun . It is moving away from the Earth with a
radial velocity of +35.8 km/s.
[3]
This is a probable
astrometric binary ,
[8] based upon
proper motion data collected during the
Hipparcos mission.
[9] The visible component shows the
spectrum of an
evolved
K-type
giant or
bright giant star with a
stellar classification of K0 II-III.
[3] The measured
angular diameter , after correction for
limb darkening , is 2.32± 0.02
mas .
[10] At an estimated distance of this star, this yields a physical size of about 14 times the
radius of the Sun .
[5] It has 1.4
[3] times the
mass of the Sun and is radiating 87
[3] times the
Sun's luminosity from its
photosphere at an
effective temperature of about 4,594 K.
[3]
References
^
a
b
c
d
e
f van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics , 474 (2): 653–664,
arXiv :
0708.1752 ,
Bibcode :
2007A&A...474..653V ,
doi :
10.1051/0004-6361:20078357 ,
S2CID
18759600 .
^
a
b
c
d Cousins, A. W. J. (1973), "Revised zero points and UBV photometry of stars in the Harvard E and F regions", Memoirs of the Royal Astronomical Society , 77 : 223–236,
Bibcode :
1973MmRAS..77..223C .
^
a
b
c
d
e
f
g
h
i
j
k Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal , 150 (3): 88,
arXiv :
1507.01466 ,
Bibcode :
2015AJ....150...88L ,
doi :
10.1088/0004-6256/150/3/88 ,
S2CID
118505114 .
^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters , 38 (5): 331,
arXiv :
1108.4971 ,
Bibcode :
2012AstL...38..331A ,
doi :
10.1134/S1063773712050015 ,
S2CID
119257644 .
^
a
b Lang, Kenneth R. (2006),
Astrophysical formulae , Astronomy and astrophysics library, vol. 1 (3rd ed.),
Birkhäuser ,
ISBN
3-540-29692-1 . The radius (R* ) is given by:
2
⋅
R
∗
=
(
55.7
⋅
2.32
⋅
10
−
3
)
AU
0.0046491
AU
/
R
⨀
≈
27.8
⋅
R
⨀
{\displaystyle {\begin{aligned}2\cdot R_{*}&={\frac {(55.7\cdot 2.32\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 27.8\cdot R_{\bigodot }\end{aligned}}}
^
a
b Soubiran, C.; Le Campion, J.-F.; Cayrel de Strobel, G.; Caillo, A. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics , 515 : A111,
arXiv :
1004.1069 ,
Bibcode :
2010A&A...515A.111S ,
doi :
10.1051/0004-6361/201014247 ,
S2CID
118362423 .
^
"iot Sgr" .
SIMBAD .
Centre de données astronomiques de Strasbourg . Retrieved 2017-07-07 .
^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society , 389 (2): 869–879,
arXiv :
0806.2878 ,
Bibcode :
2008MNRAS.389..869E ,
doi :
10.1111/j.1365-2966.2008.13596.x ,
S2CID
14878976 .
^ Frankowski, A.; et al. (March 2007), "Proper-motion binaries in the Hipparcos catalogue. Comparison with radial velocity data", Astronomy and Astrophysics , 464 (1): 377–392,
arXiv :
astro-ph/0612449 ,
Bibcode :
2007A&A...464..377F ,
doi :
10.1051/0004-6361:20065526 ,
S2CID
14010423 .
^ Richichi, A.; et al. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics , 431 (2): 773–777,
Bibcode :
2005A&A...431..773R ,
doi :
10.1051/0004-6361:20042039 .