Roy Axelsen has published a paper on the δ Scuti star EQ Eridani in the JAAVSO.
V393 Carinae is a 7th magnitude δ Scuti star which has a principal period of 0.1413 d and an amplitude of 0.2 magnitude in V. Previous publications have suggested the existence of a second period, but its duration has so far evaded discovery. In view of the uncertainty, and since the only two papers on this star were published in 1984 and 2001, DSLR photometry was performed to obtain time series data. Images were taken during 6 nights from December 2013 to March 2014. The data were analyzed using a discrete Fourier transform, which yielded a principal frequency of 7.07727 (±0.00005) cycles/day, corresponding to a period of 0.141297 (±0.000001) day. Prewhitening for this frequency revealed a harmonic frequency precisely twice that of the principal, but no further dominant frequencies could be found. O–C diagrams suggested that it would appropriate to derive a new linear ephemeris from three times of maximum obtained by another author from 1977 to 1979, combined with the 6 new times of maximum reported in this paper. The light elements are: Tmax = HJD 2456732.0484 (6) + 0.14129328 (1). It is concluded that the current principal period of this star is almost identical to the period determined approximately 37 years ago. The issue of a second period is unresolved. None was detected, but it cannot be excluded that a second pulsation frequency of low amplitude could be hidden due to a low signal to noise ratio.
Axelsen, R. (2014). Current Light Elements of the δ Scuti Star V393 Carinae. 42, 292. Retrieved from https://www.aavso.org/sites/default/files/jaavso/v42n2/292.pdf
About the author
- Roy Axelsen is Section Director of the Variable Stars Section of the AAQ and won the Page Medal in 2016.
- Variable Stars2019.06.25Photometry of Variable Stars
- Variable Stars2019.06.25The visual observation of variable stars
- Variable Stars2017.03.22Digital single lens photometry in white light: a new concept tested on data from the high amplitude δ Scuti star V703 Scorpii
- Variable Stars2016.10.14The high amplitude δ Scuti star AD Canis Minoris