L. A. Koelemay, M. A. Burton, A. P. Singh, P. M. Sheridan, J. J. Bernal, and L. M. Ziurys
described the
Laboratory and Astronomical Detection of the SiP Radical (X²Π_i): More Circumstellar Phosphorus
Astrophys. J. Lett. 940, Art. No. L11 (2022).
Dedicated observations of CW Leonis with the ARO 12 m dish at Kitt Peak as well as observations (dedicated and from a line survey) with the ARO SMT in the regions of the ²Π_3/2, J“ = 7.5, 12.5, 15.5, and 16.5 transitions of SiP. Only the J” = 12.5 and 15.5 transitions near 215.05 and 262.81 GHz appear to be unblended. While this is fine for a tentative detection, it is too little for us to qualify for a definitive detection. The authors derive peak abundances only slightly lower than CP and even slightly higher than PN, but somewhat closer to the star.

Contributor(s): H. S. P. Müller; 12, 2022