Possible Cool Prominence Materials Detected within Interplanetary Small Magnetic Flux Ropes

Previous studies indicate that interplanetary small magnetic flux ropes (SMFRs) are manifestations of microflare-associated small coronal mass ejections (CMEs), and the hot material with high-charge states heated by related microflares are found in SMFRs. Ordinary CMEs are frequently associated with prominence eruptions, and cool prominence materials are found within some magnetic clouds (MCs). Therefore, the predicted small CMEs may also be frequently associated with small prominence eruptions. In this work, we aim to search for cool prominence materials within SMFRs. We examined all the O5+ and Fe6+ fraction data obtained by the Advanced Composition Explorer (ACE) spacecraft during 1998-2008 and found that 13 SMFRs might exhibit low-charge-state signatures of unusual O5+ and/or Fe6+ abundances. One of the 13 SMFRs also exhibited signatures of high ionic charge states. We also reported a SMFR with high Fe6+ fraction, but the values of Fe6+ is a little lower than the threshold defining unusual Fe6+. However, the Solar Dynamics Observatory/Atmospheric Imaging Assembly observations confirmed that the progenitor CME of this SMFR is associated with a small eruptive prominence, and the observations also supported the prominence materials were embedded in the CME. These observations are at the edge of the capabilities of ACE/Solar Wind Ion Composition Spectrometer and it cannot be ruled out that they are solely caused by instrumental effects. If these observations are real, they provide new evidence for the conjecture that SMFRs are small-scale MCs but also imply that the connected small CMEs could be associated with flares and prominence eruptions.