Carl Eugene Heiles (born 1939) is an American astrophysicist noted for his contributions to the understanding of diffuse interstellar matter through observational radio astronomy.
While Heiles was still a graduate student at Princeton, he wrote a paper with Michel Hénon about a third integral of motion in axisymmetric potentials, from which the Hénon-Heiles equation is derived.
[5] Heiles has also been pivotal in understanding the diffuse gas in the interstellar medium, primarily through observation of the hydrogen line.
His role in this field is such that a conference at Arecibo Observatory in Puerto Rico on diffuse matter was held in honor of Heiles's 65th birthday.
[6] Observations of this gas have helped develop a better understanding of star formation and galactic gravitational and magnetic fields.