A remnant planetary core in the hot-Neptune desert.

The interiors of giant planets remain poorly understood. Even for the planets in the Solar System, difficulties in observation lead to large uncertainties in the properties of planetary cores. Exoplanets that have undergone rare evolutionary processes provide a route to understanding planetary interiors. Planets found in and near the typically barren hot-Neptune 'desert'1,2 (a region in mass-radius space that contains few planets) have proved to be particularly valuable in this regard. These planets include HD149026b3, which is thought to have an unusually massive core, and recent discoveries such as LTT9779b4 and NGTS-4b5, on which photoevaporation has removed a substantial part of their outer atmospheres. Here we report observations of the planet TOI-849b, which has a radius smaller than Neptune's but an anomalously large mass of [Formula: see text] Earth masses and a density of [Formula: see text] grams per cubic centimetre, similar to Earth's. Interior-structure models suggest that any gaseous envelope of pure hydrogen and helium consists of no more than [Formula: see text] per cent of the total planetary mass. The planet could have been a gas giant before undergoing extreme mass loss via thermal self-disruption or giant planet collisions, or it could have avoided substantial gas accretion, perhaps through gap opening or late formation6. Although photoevaporation rates cannot account for the mass loss required to reduce a Jupiter-like gas giant, they can remove a small (a few Earth masses) hydrogen and helium envelope on timescales of several billion years, implying that any remaining atmosphere on TOI-849b is likely to be enriched by water or other volatiles from the planetary interior. We conclude that TOI-849b is the remnant core of a giant planet.

Antibiotic resistance in invasive Streptococcus pneumoniae isolates identified in Scotland between 1999 and 2007.

Data from 4727 invasive isolates of Streptococcus pneumoniae submitted to the Scottish Haemophilus, Legionella, Meningococcus and Pneumococcus Reference Laboratory between 1999 and 2007 were analysed to establish susceptibility profiles to penicillin, erythromycin and cefotaxime. Pneumococcal resistance to penicillin over the study period remained low, with only 0.2 % (n=7/4727) of isolates falling into this category (MIC ≥2 mg l(-1)). These isolates have been sporadic, and have mainly represented serogroup 14 (ST9) and 9 (ST156). In comparison, the 'intermediate sensitivity' group (MIC 0.12-1 mg l(-1)) ranged between 2 and 6 % per year, the majority from serogroup 9 (ST156). Over the study period, we found that 12 % (n=585/4727) of isolates were erythromycin-resistant (MIC >0.5 mg l(-1)), with the majority (n=467; 80 %) of these isolates identified as serogroup 14 (ST9). Cephalosporin resistance (cefotaxime MIC >1 mg l(-1)) was found in only 0.06 % (n=2/3135) of isolates. Internationally recognized clones (Pneumococcal Molecular Epidemiology Network) accounted for 35 % (n=28/81) of the penicillin non-susceptible isolates and 75 % (n=248/330) of the macrolide-resistant isolates, with ST9 and ST306 predominating. Between 1999 and 2007 we found that 11.6 % (n=18/155) of the penicillin non-susceptible isolates and 4.8 % (n=28/585) of the macrolide-resistant isolates were from serogroups not covered by the 7-valent conjugate pneumococcal vaccine in use in the UK since 2006. Susceptibility to first-line antimicrobial agents for invasive pneumococcal disease in Scotland remained high over the period 1999-2007.