Andre et al. (1993) discovered a class 0: objects with strong submillimeter emission, but very faint at λ < 10 μ m {\displaystyle {\lambda }<10{\mu }m} .
Andre et al. (1993) objavil triedu 0: objekty so silnou submilimetrovou emisiou, ale veľmi slabé v λ < 10 μ m {\displaystyle {\lambda }<10{\mu }m} .