None known (a possible companion object has been suggested, but remains unconfirmed, and further studies suggest that its existence is unlikely)
Optimum Visibility
October
Notes
The remnant core of a long-expired redgiant, van Maanen's Star was discovered by Adrian van Maanen in 1917, and at that time was only the third white dwarf to have been identified. It is an extraordinarily dense object, with an estimated two-thirds of the mass of the Sun compacted into a region only slightly larger than the Earth.