Stable Up-Down Quark Matter Nuggets, Quark Star Crusts, and a New Family of White Dwarfs

The possible existence of stable up-down quark matter ($ud$QM) was recently proposed, and it was shown that the properties of $ud$QM stars are consistent with various pulsar observations. In this work we investigate the stability of $ud$QM nuggets and found at certain size those objects are more stable than others if a large symmetry energy and a small surface tension were adopted. In such cases, a crust made of $ud$QM nuggets exists in quark stars. A new family of white dwarfs comprised entirely of $ud$QM nuggets and electrons were also obtained, where the maximum mass approaches to the Chandrasekhar limit.