Search

A sample of the 6.7 GHz methanol maser sources found in the unbiased survey of the Galactic plane taken with the Toruń 32 m dish has been observed using the Mk II -- Ca baseline of MERLIN. The phase-referencing observations resulted in maser positional accuracies of 50 mas in RA and 100 mas in Dec for strong single-peak targets. Preliminary results are presented for the first set of sources. The coordinates of methanol sources are given. Comparison with infrared and radio continuum maps revealed that 7 out of 8 targets are associated with far infrared emission at 60 μ m, while 2 of them show 2.2 μ m emission and are accompanied by ultracompact H II regions seen in the 5 and/or 21 cm continuum.

Measurements of trace gases in planetary atmospheres help us explore chemical conditions different to those on Earth. Our nearest neighbour, Venus, has cloud decks that are temperate but hyperacidic. Here we report the apparent presence of phosphine (PH3) gas in Venus’s atmosphere, where any phosphorus should be in oxidized forms. Single-line millimetre-waveband spectral detections (quality up to ~15σ) from the JCMT and ALMA telescopes have no other plausible identification. Atmospheric PH3 at ~20 ppb abundance is inferred. The presence of PH3 is unexplained after exhaustive study of steady-state chemistry and photochemical pathways, with no currently known abiotic production routes in Venus’s atmosphere, clouds, surface and subsurface, or from lightning, volcanic or meteoritic delivery. PH3 could originate from unknown photochemistry or geochemistry, or, by analogy with biological production of PH3 on Earth, from the presence of life. Other PH3 spectral features should be sought, while in situ cloud and surface sampling could examine sources of this gas. The detection of ~20 ppb of phosphine in Venus clouds by observations in the millimetre-wavelength range from JCMT and ALMA is puzzling, because according to our knowledge of Venus, no phosphine should be there. As the most plausible formation paths do not work, the source could be unknown chemical processes—maybe even life?