Akademik Veri Yönetim Sistemi
ASTROPHYSICAL JOURNAL, cilt.420, sa.1, ss.373-386, 1994 (SCI-Expanded)
A new formulation for the starspot model is derived. The resulting expressions are equivalent to others which appeared in the literature but have the advantage of much greater transparency and are easier to use. Three sets of equations allow the computation of light curves according to three different limb-darkening cases quadratic, linear, and without limb darkening). The linear limb darkening law appears sufficient in producing light curves at longer wavelengths, including V-band. This is also applicable to all colors of UBV for the models with sufficiently high effective temperatures (T(eff) > 5000 K). Belts, composed of many identical spots evenly distributed around the equator or any latitude, are also investigated in these limb-darkening cases. With a sufficient number (n > 9) of spots, a belt can replace a polar spot. A polar spot or a belt is essential in the starspot modeling, if the maximum light level of modulation does not represent a case in which no spots are present on the visible disk. The synthetic light curves computed by using the present formulation are fitted to the light curves of BY Dra and HK Lac. Multiple spots and solar analogy in starspot modeling is discussed. Multicolor photometry should be sufficient to reach a unique solution regarding spot sizes, shapes, positions, and temperatures if inclination of the rotation axes is presumably known. The spot shapes are expressible using many, but smaller, circular spots.