While an undergraduate student at Cornell he became acquainted with the Planetary Scientist Carl Sagan.
Henry wrote several papers with Sagan on the organic chemistry in planetary atmospheres between 1985 and 1991.
[3] He established a series titled The solar neighborhood in The Astronomical Journal that now has over twenty chapters.
He is on the CRIRES team that failed to confirm any planetary companions for the nearby star VB 10.
[4] He was elected a Legacy Fellow of the American Astronomical Society in 2020.