Notes on Two Long-Period Variables, RT Cygni an U Persei

On the period history of χ Cygni

We discuss the light variability of the Mira variable χ Cygni, present a homogeneous set of times of minimum and maximum light since its discovery date in 1686, and analyse the variations of the pulsation period. There is a substantial cycleto-cycle variation in the pulsations (standard error ∼ 6. d5) with quite strong evidence for a linearly increasing period. Quasicyclic patterns in the O−C d...

Notes on Complex Variables

Lecture Notes on Induction Variables

Once we have identified a loop (e.g., natural loop), one of the central questions about it is, which variables are induction variables of the loop. In for-loops, there are syntactical indicators if the step is of the form i++. But that alone does not make i a proper induction variable, because there could be further assignments to i. Furthermore, other variables could effectively be induction v...

Notes on Continuous Random Variables

Continuous random variables are random quantities that are measured on a continuous scale. They can usually take on any value over some interval, which distinguishes them from discrete random variables, which can take on only a sequence of values, usually integers. Typically random variables that represent, for example, time or distance will be continuous rather than discrete. Just as we descri...

Long Period Variables detected by ISO in the SMC

This article presents the study of the light–curves extracted from the MACHO database of a sample of stars observed by the Infrared Space Observatory in the Small Magellanic Cloud. These stars belong to the ISO–Mini-Survey catalogue of the Magellanic Clouds (ISO–MCMS, Loup et al. in preparation). Most of them are in the asymptotic giant branch (AGB) and supergiant phases. The dominant period an...