Predicted Phases of regular LPVs (C- or S-type)

For bright northern Carbon- and S-star regular pulsators (Miras, SRAs [, SRBs]) I maintain a list with predictions of the pulsation phase, to see if they may be worthwhile to observe spectroscopically.

The phases are derived based on the GCVS pulsation periods and the last date of maximum (or maxima, if more than one). Maximum light in the visible have phase=0.0 (note that infra-red / bolometric light curves may peak as late as visual phase = 0.25).

The dates of maximum are estimated from the lightcurves by "eyeball fit". Typically, uncertainties are 10 days. For stars that are well-observed the uncertainty may be as little as 5 days, but for sparser lightcurves (or those with broad maxima) the uncertainty may be 15-20 days or more. Also the actual interval between two maxima may differ from the GCVS pulsation period (which is a historic average over many pulsation cycles): some Miras are quite stable pulsators while others have more cycle-to-cycle variations or long-term variations.

Phases >1.0 denote that the maximum is from a previous pulsation cycle (subtract a whole number to get phase between 0 and 1).

Multiple phase entries are derived from more than 1 maximum (the smaller phase is then from the most recent maximum estimate and usually [but not always] more reliable); larger differences in phases for 1 star are an indication of the uncertainty in phase determination.

Most maxima are taken from (visual) lightcurves on the AAVSO website. For some weaker stars not observed by AAVSO I occasionally use surveys such as ASAS-SN or KWS.

Predictions are made for the following dates: