A dark yellow supergiant, a semi-regular variable star of RV Tauri type, one degree south of β Scuti (4.2 mm). Its brightness varies from 4.9 mag to 8.2 mag in a period of five months - the main period being 140 days. The deep minimum may be caused by carbon particles forming in the star's atmosphere. It is within the reach of a telescope, as it is the brightest RV Tauri variable star: it seems to oscillate at least in two overlapping periods and at its maximum it is at least 8,000 times more luminous than the Sun. It often changes brightness between 5-6 mag, but after four or five such cycles it drops to 8th magnitude. It is about 2,500 light years away. Similar stars have been found not only in parts of the Milky Way, but also in globular clusters, even in the center of the Galaxy itself.