While the database is still off-line for server repairs, we have another look at some early results of the ongoing data analysis. Today we look at the young T-Tauri star LkHa141 in the Pelican nebula target region. Similar to the example from two weeks ago, we show a phase plot of the R-band magnitudes of the star. The star shows periodic variations with a period of about 8.45d. Thus, it is one of the slow rotators. Most likely the star is still linked to the inner parts of its accretion disk by magnetic fields.
This time we do not plot every individual data point. Rather we are showing as solid lines a running median of the light curve in the phase plot every three months. The colour coding is like in the last example. Blue lines represent the earliest and red lines the latest data. The colour bar at the right gives an indication where in the light curve each solid line is.
During the first half of available HOYS data, the periodic variability has very low amplitudes and is basically not detectable. There are one or two 6-months periods were a clear amplitude of about 0.1mag can be observed. In the second half, more higher amplitude behaviour can be seen. At about 70% into the data, we can see periodic variability for about 1yr. These variations then get shallower and reappear towards the very end of the investigated data. The difference is that the maxima are at a different phase. They move from ph=0.2 towards ph=0.8. In other words, we might see two different spots at different times on the stellar surface, which form on different parts of the star. In essence, the second spot is at a longitude that is about 145deg different to the first spot. We will now see what the spot properties are (temperature and size). And there are a number of young stars in our sample were we can do this analysis.