... Estimates are obtained for the limits of variability of the parameters of harmonic components that can be determined on a specified time grid. ... The second is the same as the first, but for model time series on a temporal grid determined by the real series with model harmonic components and with the parameters for the harmonic components obtained by solving the first problem. ... Thus, our problem involves choosing a method for determining the harmonic components of time series 72 TABLE 1. ...

... We also analyze Chandra X-ray archive data for the Mon R2 region and find IRS 3 A and IRS 3 C to be sources of hard (3 - 10 keV) and variable X-ray emission , suggesting plasma temperatures of at least 50 в 106 K. The similarity of the X-ray properties to those of Class I protostars suggests magnetic interaction between the protostars and their circumstellar disks to be the origin of the X-ray ... 2002). ... Upper Upper Lower Lower K-band Images of Mon R2 IRS 3. ... X-ray results. ...