Pi1 Ursae Majoris

Pi1 Ursae Majoris (Pi1 UMa, π¹ Ursae Majoris, π¹ UMa) is a yellow G-type main sequence dwarf with a mean apparent magnitude of +5.63.

[11] It is classified as a BY Draconis type variable star and its brightness varies by 0.08 magnitudes.

[7][10] An excess of infrared radiation has been detected from this system, which suggests the presence of a debris disk.

The best fit to the data indicates that there is a ring of fine debris out to a radius of about 0.4 AU, consisting of 0.25 μm grains of amorphous silicates or crystalline forsterite.

There may also be a wider ring of larger (10 μm) grains out to a distance of 16 AU.

A light curve for pi 1 Ursae Majoris, plotted from TESS data. [ 12 ] The main plot shows the variation over several weeks, and the inset plot shows the same data folded, assuming a 4.9 day period, [ 13 ] and averaged into 250 phase bins.