Phosphaethyne (HCP) was detected toward
IRC +10216 by
Agúndez et al. in 2007.
Four consecutive rotational transitions were observed using the IRAM
Milam et al. confirmed the detection in 2008
and observed HCP toward both IRC +10216 and CRL 2688, also known as the
Egg nebula, a
protoplanetary system. An earlier
attempt reported in 1990 by Turner et al.
to detect HCP toward IRC +10216 was unsuccessful.