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

TL;DR

This study analyzes 24 years of multiband data on LO Peg, revealing its surface differential rotation, star-spot cycles, flares, and activity evolution, highlighting solar-like SDR patterns and spot dynamics on this ultrafast rotator.

Contribution

It provides a comprehensive long-term analysis of LO Peg's surface activity, including SDR, star-spot evolution, and flare activity, using multiwavelength observations.

Findings

Surface differential rotation shows a solar-like pattern.

A ~2.7-year cycle in rotational period variation.

20 optical flares detected with high energy and frequency.

Abstract

Using the wealth of ~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 (UFR) 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 ~2.7 yr appears to be present in rotational period variation. During the observations, 20 optical flares are detected with a flare frequency of 1 flare per two days and with flare energy of 10^{31-34} erg. The surface coverage of cool spots is found to be in the range of 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.