LO Peg: surface differential rotation, flares, and spot-topographic evolution

作者：Karmakar Subhajeet; Pandey J C; Savanov I S; Tas G; Pandey S B; Misra K; Joshi S; Dmitrienko E S; Sakamoto T; Gehrels N; Okajima T

来源：Monthly Notices of the Royal Astronomical Society, 2016, 459(3): 3112-3129.

DOI：10.1093/mnras/stw855

• stars: activity
• stars: flare
• stars: imaging
• stars: individual: (LO Peg)
• stars: late-type
• starspots

Using the wealth of similar to 24 yr multiband data, we present an in-depth study of the star-spot cycles, surface differential rotations (SDR), optical flares, evolution of star-spot distributions, and coronal activities on the surface of young, single, main-sequence, ultrafast rotator LO Peg. From the long-term V-band photometry, we derive rotational period of LO Peg to be 0.4231 +/- 0.0001 d. Using the seasonal variations on the rotational period, the SDR pattern is investigated, and shows a solar-like pattern of SDR. A cyclic pattern with period of similar to 2.7 yr appears to be present in rotational period variation. During the observations, 20 optical flares are detected with a flare frequency of similar to 1 flare per two days and with flare energy of similar to 10(31-34) erg. The surface coverage of cool spots is found to be in the range of similar to 9-26 per cent. It appears that the high- and low-latitude spots are interchanging their positions. Quasi-simultaneous observations in X-ray, UV, and optical photometric bands show a signature of an excess of X-ray and UV activities in spotted regions.

• 出版日期2016-7-1