He has co-discovered the periodic comets 111P/Helin–Roman–Crockett, 117P/Helin–Roman–Alu and 132P/Helin–Roman–Alu.
Tamén descubriu varios cometas, como os cometas periódicos 111P/Helin–Roman–Crockett, 117P/Helin–Roman–Alu e 132P/Helin–Roman–Alu.