Published data indicate a substantial increase in the differential rotation parameter ∆Ω of stars hotter than 6700 K. By analyzing the shape of the light curves and the presence of a specific set of peaks in their power spectra, we have found that 47 of 57 objects with Teff greater than 7500 K that were studied can be identified as pulsating stars and only 10, as stars with brightness variation owing to rotational modulation. After eliminating the pulsating variables, for the stars with Teff greater than 7500 K the average value of ∆Ω= 0.051±0.01 rad/day. This conclusion conflicts with our earlier assumption that the peaks in the power spectra for ROTD stars are caused by a possible manifestation of differential rotation. Further independent evidence for a low value of ∆Ω for stars in spectral class A has been obtained from Zeeman-Doppler charts for the star γ Gem, with an estimate for the differential rotation parameter of the star of 0.0073±0.0023 rad/day.

中文翻译：

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A类光谱中恒星的微分自转

已发表的数据表明，温度高于 6700 K 的恒星的微分旋转参数 ΔΩ 大幅增加。通过分析光变曲线的形状和功率谱中特定峰值的存在，我们发现 57 个天体中的 47 个所研究的 Teff 大于 7500 K 的恒星可以被识别为脉动星，只有 10 颗是由于旋转调制而亮度变化的恒星。消除脉动变量后，对于 Teff 大于 7500 K 的恒星，ΔΩ 的平均值 = 0.051±0.01 rad/day。这个结论与我们早先的假设相冲突，即 ROTD 恒星的功率谱中的峰值可能是由差速旋转的可能表现引起的。