This star was classified aspeculiar withspectral type A0p in theHenry Draper Catalogue, published 1918–1924. This class was based on the strength of a pair oflines of ionized silicon in itsstellar spectrum. In 1931,W. W. Morgan discovered that the spectrum of the star varied over a period of several days. In particular, the lines of ionized chromium and europium varied considerably in intensity, ranging from strong to very faint. This variation shares similarities to those ofα2 Canum Venaticorum. The two sets of lines vary in the opposite direction from each other, so that the chromium lines were minimum when the europium lines were maximized, and vice versa.[14] In 1947,A. J. Deutsch found a period of 9.295 days for the variation.[15]
H. W. Babcock examined the star usingCoudé spectrograms in 1947, finding a generalmagnetic field with a strength of around5,500 Gauss at the poles. At the time, that was the strongest magnetic field that had been observed in a star. He noticed that the magnetic field was variable, and it showed the oppositepolarity when the lines of europium were at a minimum compared to when they were at the maximum.[16] Subsequent observations showed the period and amplitude of the variation to be stable over time.[8] In 1950,D. W. N. Stibbs first proposed an 'oblique rotator model' to explain the properties of this star,[17] in which its magnetic field is locked at an angle to theaxis of rotation.[9]
The star displaysradial velocity variations that suggest it is a single-linedspectroscopic binary with a period of 4.4 years and anorbital eccentricity of 0.21.[8] The visible component has astellar classification of A1p SrCrEu,[4] which indicates this is a magnetic peculiarAp star with prominent abundance anomalies of strontium, chromium, and europium in itsatmosphere. It has double the mass and nearly twice the radius of the Sun.[9][10] The star is an estimated 234 million years old and is spinning with a rotation rate of 9.3 days.[9] It is radiating 42 times the luminosity of the Sun from itsphotosphere at aneffective temperature of 9,850 K.[9]
In 1950, Douglas Walter Noble Stibbs published data showing that HD 125248's brightnessvaries.[19] It is anAlpha2 Canum Venaticorum variable star with a brightness that is modulated by its rotation.[2] MagneticDoppler imaging of the star suggests the magnetic field deviates strongly from a simpledipole geometry.[9]
^Houk, Nancy; Smith-Moore, M. (1978),Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 4, Ann Arbor: Dept. of Astronomy, University of Michigan,Bibcode:1988mcts.book.....H.
^Morgan, W. W. (July 1931), "Studies in Peculiar Stellar Spectra. II. The Spectrum of B. D. 18°3789",Astrophysical Journal,74: 24,Bibcode:1931ApJ....74...24M,doi:10.1086/143322.
Monier, R. (September 1992), "Applications of the infrared flux method to 3 cool AP stars (78 Virginis, 52 Herculis A and CS Virginis) and comparison of their energy distributions to model atmospheres",Astronomy and Astrophysics,263:175–182,Bibcode:1992A&A...263..175M.
Mathys, G. (March 1992), "The inhomogeneous distribution of oxygen on the surface of the magnetic AP star HD 125248",Astronomy and Astrophysics,256:L31 –L34,Bibcode:1992A&A...256L..31M.
Catalano, F. A.; et al. (September 1992), "The near-infrared variation of the magnetic star HD 125248",Astronomy and Astrophysics,263:203–207,Bibcode:1992A&A...263..203C.
Mathys, G.; Stenflo, J. O. (1988), de Strobel, G. Cayrel; Spite, Monique (eds.), "Spectropolarimetry of Magnetic Stars: HD 125248",The Impact of Very High S/N Spectroscopy on Stellar Physics: Proceedings of the 132nd Symposium of the International Astronomical Union held in Paris, France, June 29-July 3, 1987. International Astronomical Union Symposium no. 132, vol. 132, Dordrecht: Kluwer Academic Publishers, p. 317,Bibcode:1988IAUS..132..317M.
Pyper, D. M.; Adelman, S. J. (March 1985), "Spectrophotometry of peculiar B and A stars. XVII. 63 Andromedae, HD 34452, epsilon Ursae Majoris, CQ Ursae Majoris, CU Virginis, CS Virginis and beta Coronae Borealis",Astronomy and Astrophysics Supplement Series,59:369–397,Bibcode:1985A&AS...59..369P.
Blanco, C.; et al. (February 1978), "Photoelectric observations of the Ap stars HD 125248, HD 134798 and HD 184905",Astronomy and Astrophysics Supplement Series,31:205–208,Bibcode:1978A&AS...31..205B.
Pilachowski, C. A.; Bonsack, W. K. (April 1975), "The effect of line blocking on the light curves of the Ap star HR 5355 (HD 125248)",Publications of the Astronomical Society of the Pacific,87:221–229,Bibcode:1975PASP...87..221P,doi:10.1086/129747,S2CID122505963.
Maitzen, H. M.; Moffat, A. F. J. (February 1972), "Eleven-band photometry of the magnetic variable HD 125248",Astronomy and Astrophysics,16: 385,Bibcode:1972A&A....16..385M.
Maitzen, H. M.; Rakosch, K. D. (July 1970), "UBV observations of the magnetic variable HD 125248",Astronomy and Astrophysics,7: 10,Bibcode:1970A&A.....7...10M.
Preston, George W. (June 1970), "The Large Variable Magnetic Field of HD 126515 and its Implications for the Rigid-Rotator Model of Magnetic Stars",Astrophysical Journal,160: 1059,Bibcode:1970ApJ...160.1059P,doi:10.1086/150493.
Maitzen, H. M. (February 1970), "Observations Photoelectriques de HD 125248",Information Bulletin on Variable Stars,421 (1): 1,Bibcode:1970IBVS..421....1M.
Hockey, M. S. (1969), "Spectrophotometric observations of the magnetic variable HD 125248",Monthly Notices of the Royal Astronomical Society,142 (4): 543,Bibcode:1969MNRAS.142..543H,doi:10.1093/mnras/142.4.543.
Adam, M. G. (October 1965), "The magnetic variable HD 125248",The Observatory,85:204–206,Bibcode:1965Obs....85..204A.
