2012 programme

Sun 09:30-10:30

Near Infrared Phase Lag of Mira Variable, R Carinae

Anthony Dutton, Gregorie Bond and Julian West

Astronomical Association of Queensland

Near infrared (NIR) photometry in the J and H bands has been undertaken over a 4 year period on the oxygen rich Mira type variable star R Carinae. Comparison of near infrared photometry with visual observations and DSLR photometry reveals the NIR light curve is asymmetric with the star rising to maximum brightness at a slower rate than it falls, also the NIR maximum is broader with a lower amplitude than the visual maximum. The measured phase lag of 40 to 60 days between visual maximum the NIR maximum is at the lower limit of published data for other oxygen rich Mira stars. This presentation compares the J and H band photometry results with visual observations and DSLR photometry. Spectra measured throughout 2011 with a 0.3nm resolution spectrograph will be used to consider changes in spectral classification, temperature and metallic oxide absorptions. The photometry and spectroscopy will be used to examine possible causes of the phase lag such as absorption of visual wavelengths by Vanadium Oxide molecules that form in the star’s atmosphere.