NGC 1555, sometimes known as Hind's Variable
Nebula, is a variable nebula, illuminated by the star T Tauri,
located in the constellation Taurus. It is a Herbig–Haro object.
Herbig–Haro objects (HH) are small patches of nebulosity
associated with newly born stars, and are formed when narrow
jets of gas ejected by young stars collide with clouds of gas
and dust nearby at speeds of several hundred kilometres per
second. Herbig–Haro objects are ubiquitous in star-forming
regions, and several are often seen around a single star,
aligned along its rotational axis.