Astronomy Picture of the Day . NGC 6357: Cathedral to Massive Stars . ... 27.03.2016 . ... Credit Copyright: NASA , ESA and Jes s Ma z Apell niz ( IAA , Spain); Acknowledgement: Davide De Martin ( ESA/Hubble ) Explanation: How massive can a normal star be? ... Component stars would still remain near 100 solar masses, making them among the more massive stars currently on record. Toward the bottom of the image, stars are still forming in the associated emission nebula NGC 6357 . ... March 2016 . ...