During 2009–2010, HD 43317 was observed by the CoRoT space telescope during the LRa03 (long run) sequence for asteroseismological purposes. This program lasted for a period of 150.41 days, during which the star was under almost constant observation. After being combined with HARPS data, the star was classified as a hybrid slowly pulsating B-type star and a Beta Cephei variable. Both g (gravity) and p (pressure) mode pulsations were detected. It is spinning rapidly at about half of its critical velocity.[10]
The photometry and spectrometry of HD 43317 showed rotational modulation of regions with temperature or chemical differences. These are an indirect indicator of a magnetic field. In addition, X-ray emission was detected by ROSAT, which also suggests a potential magnetic field. A magnetic field was directly detected with the Téléscope Bernard Lyot during 2012. The longitudinal field strength was found to vary with the 21.5 h rotation period, ranging from −140 G to 180 G.[11] Modelling of the star's dipolar field found a strength between 1 and 1.5 kG. This is strong enough to force uniform rotation in the outer radiative zone of the star.[5]
Light curves for HD 43317, plotted from CoRoT data.[12] The star's average amplitude has been subtracted, leaving only the time variability.
The CoRoT light curve of the star displays 35 different frequencies, of which 28 are not related to the rotation period. Seismic modeling of the star determined a stellar mass equal to 5.8 times the mass of the Sun. At the core, the central mass fraction of hydrogen is 54%, compared to 70% for a newly formed main sequence star and 0.1% at the end of main sequence lifetime. Spectroscopic analysis shows an effective temperature of around 17,350 in the stellar atmosphere. A refined estimate of the surface magnetic field strength found a value of 1,312±332 G.[13] The magnetic field near the core has a seismically modelled strength of 5×105 G. HD 43317 is the first main sequence star for which an interior magnetic field strength has been inferred.[3]
This star has an estimated radius of 3.39 times the girth of the Sun,[7] and is radiating 737.5[2] times the Sun's luminosity. It is about 28.4 million years old.[7]
^ abcdefghLecoanet, Daniel; et al. (May 2022), "Asteroseismic inference of the near-core magnetic field strength in the main-sequence B star HD 43317", Monthly Notices of the Royal Astronomical Society: Letters, 512 (1): L16 –L20, arXiv:2202.03440, Bibcode:2022MNRAS.512L..16L, doi:10.1093/mnrasl/slac013.
^Lesh, Janet Rountree (December 1968), "The Kinematics of the Gould Belt: an Expanding Group?", Astrophysical Journal Supplement, 17: 371, Bibcode:1968ApJS...17..371L, doi:10.1086/190179.
