Interstellar Communication Channel Search of 49 Stars Closer than 11.5 PC

Abstract

AbstractWe report on a search for narrow band emissions from the vicinity of 36 solar type (F6 to K4) target stars and 13 other non-solar type stars within 11.5 parsecs at 5 possible interstellar beacon frequencies of π*fH, 2π*fH, e*fOH, e*(fOH+fH) and3He (4.462, 8.925, 4.532, 8.393 and 8.666 GHz respectively). The frequencies were selected by scaling important naturally occurring lines by fundamental constants. The stars were selected for a distance of less than 11.5 parsecs to give sufficient time for a nearby civilisation to have detected early Earth radio leakage signals and to have replied. The search was carried using the 64-m Parkes telescope with the Phoenix instrumentation and the 22-m Mopra telescope for candidate verification. The instrument combination allowed for a low interference, high resolution, high sensitivity search. We did not detect any signals from any of the target stars. If a civilisation at a distance of 10 pc had beamed 10 kW signals at us using a 100-m dish, we would have detected the transmission at the 10 sigma level. Thus we can exclude signals above this level.