A light curve for Chi Aquarii, plotted from Hipparcos data[9]
This is a red giant star with a spectral classification of M3 III.[3] The interferometry-measured angular diameter of this star is 6.70 ± 0.15 mas,[10] which, at its estimated distance, equates to a physical radius of about 137 times the radius of the Sun.[lower-alpha 1] It is classified as a semi-regular variable star and its brightness varies by an amplitude of 0.0636 in magnitude.[11] The identified pulsation periods are 32.3, 38.5, and 44.9 days.[12]
Notes
↑ 1.01.1The radius (R*) is given by [math]\displaystyle{ 2\cdot R_* = \frac{(190\cdot 6.70\cdot 10^{-3})\ \text{AU}}{0.0046491\ \text{AU}/R_\bigodot} \approx 274\cdot R_\bigodot. }[/math][13]
↑ 2.02.1Samus, N. N. et al. (2009), "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)", VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S1, Bibcode: 2009yCat....102025S.
↑ 4.04.1Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series34: 1–49, Bibcode: 1978A&AS...34....1N.
↑Famaey, B. et al. (May 2009), "Spectroscopic binaries among Hipparcos M giants. I. Data, orbits, and intrinsic variations", Astronomy and Astrophysics498 (2): 627–640, doi:10.1051/0004-6361/200810698, Bibcode: 2009A&A...498..627F.
↑Richichi, A.; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics431 (2): 773–777, doi:10.1051/0004-6361:20042039, Bibcode: 2005A&A...431..773R.
