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We use a long‐term record of ground‐based mid‐infrared (7.9–24.5 μm) observations, captured between 1984 and late 2019 from 3‐m and 8‐m class observatories (mainly NASA's Infrared Telescope Facility, ESO's Very Large Telescope, and the Subaru Telescope), to characterize the long‐term, multi‐decade variability of the thermal and aerosol structure in Jupiter's atmosphere. In this study, spectral cubes assembled from images in multiple filters are inverted to provide estimations of stratospheric and tropospheric temperatures and tropospheric aerosol opacity. We find evidence of non‐seasonal and quasi‐seasonal variations of the stratospheric temperatures at 10 mbar, with a permanent hemispherical asymmetry at mid‐latitudes, where the northern mid‐latitudes are overall warmer than southern mid‐latitudes. A correlation analysis between stratospheric and tropospheric temperature variations reveals a moderate anticorrelation between the 10‐mbar and 330‐mbar temperatures at the equator, revealing that upper‐tropospheric equatorial temperatures are coupled to Jupiter's Equatorial Stratospheric Oscillation. The North and South Equatorial Belts show temporal variability in their aerosol opacity and tropospheric temperatures that are in approximate antiphase with one another, with moderate negative correlations in the North Equatorial Belt and South Equatorial Belt changes between conjugate latitudes at 10°–16°. This long‐term anticorrelation between belts separated by ∼15° is still not understood. Finally we characterize the lag between thermal and aerosol opacity changes at a number of latitudes, finding that aerosol variations tend to lag after thermal variations by around 6 months at multiple latitudes. Plain Language Summary: Jupiter's atmosphere displays a wide variety of perturbations in its temperatures, clouds and aerosols. In this study, we use a large set of ground‐based observations captured in the mid‐infrared between 1984 and 2019 to characterize long‐term changes in the temperatures and aerosols. This long‐term analysis show a number of cyclic disturbances, and allows us to distinguish between seasonal and non‐seasonal changes in Jupiter's atmosphere. In particular, we observe that the northern mid‐latitudes above 30° are continuously warmer than their counterpart latitudes in the south at 10 mbar pressure level (the stratosphere), potentially due to differences in the polar haze in Jupiter, which extends to lower latitudes in the north compared to the south. Additionally, our study reveals for the first time that the thermal oscillation present in Jupiter's equatorial stratosphere at the 10‐mbar pressure level (known as Jupiter's Equatorial Stratospheric Oscillation) is also observed to descend to higher pressures (330 mbar), meaning that it is not confined to the stratosphere. Finally, we also discuss the lag between temperature and aerosol changes at diverse latitudes to try to identify the mechanisms responsible for the different atmospheric disturbances observed on Jupiter. Key Points: Ground‐based multi‐wavelength images are used to compute stratospheric and tropospheric temperature and tropospheric aerosol opacity mapsResults reveal that upper‐tropospheric equatorial temperatures are coupled to Jupiter's Equatorial Stratospheric OscillationStratospheric temperatures at 10 mbar show a permanent hemispherical asymmetry at mid‐latitudes, with northern mid‐latitudes overall warmer than their counterparts [ABSTRACT FROM AUTHOR]

The formation of massive stars in dense and cold molecular clouds is a fundamental problem in star formation. In this work, we studied three compact massive star-forming regions, M8E, RAFGL 6366S, and IRAS 18317−0513, to investigate the environment of massive star formation, specifically the possibility of a local feedback process. Our new mid-infrared observations using miniTAO/MAX38 at 31 and 37 μm resolved individual objects in each region and allowed us to obtain their individual luminosities and masses. Together with existence/absence of ultra-compact H  ii regions, it is suggested that less-massive objects are more evolved than the more-massive objects in two out of the three regions. Because the objects that are more massive evolve faster, those that are less massive form earlier. This formation trend of local mass-sequential star was first suggested in 0.1 pc-scale massive star-forming regions. Therefore, feedback, such as outflows, jets, or radiative heating, from previously formed lower-mass young stellar objects might affect the environment of parental clouds and lead to next-generation massive young stellar objects. [ABSTRACT FROM AUTHOR]

Utilizing several instruments on 4–8 m telescopes, we have observed a large sample of objects in the mid-infrared (8–13  μ m). These comprise a few evolved stars, multiple envelopes of embedded young stellar objects (YSOs) or compact H-II regions, and several sightlines through the interstellar medium (ISM). The latter is where dust resides – and is potentially modified – between its formation in evolved stellar outflows and deposition in molecular clouds. In most objects, we detect not only the well-known 9.7  μ m absorption feature of amorphous silicates but also a second absorption band around 11.1  μ m whose carrier is attributed to crystalline forsterite. We propose that crystalline silicates are essentially ubiquitous in the ISM and earliest phases of star formation, and are evolutionary precursors to T-Tauri and Herbig stars where such silicates have been commonly found. Modelling shows that in most YSOs, H-II regions and ISM cases, the forsterite mass fraction is between 1 and 2 per cent, suggesting that the younger phases inherit their abundance from the ISM. However, several sources show much stronger features (abundances ≥3 per cent). This suggests that significant processing, perhaps crystallization by thermal annealing, occurs early on in star formation. Most intriguing is the first detection of crystalline silicate in the diffuse ISM. We propose that our observed abundance is consistent with a mass fraction of crystalline silicates of 10–20 per cent injected into the ISM, along with commonly accepted lifetimes against their destruction, but only if cosmic ray-induced amorphization is insignificant over a few Giga years. [ABSTRACT FROM AUTHOR]

We present high spatial resolution radio and near-infrared hydrogen recombination line observations of the southern massive star forming region G333.6−0.2. The 3.4-cm continuum peak is found slightly offset from the infrared (IR) source. The H90α spectra show for the first time a double-peak profile at some positions. The complex velocity structure may be accounted for by champagne outflows, which may also explain the offset between the radio and IR sources. The 2.17-μm Brγ image and H90α map are combined to construct an extinction map which shows a trend probably set by the blister nature of the H ii region. The total number of Lyman continuum photons in the central 50-arcsec is estimated to be equivalent to that emitted by up to 19 O7V stars. [ABSTRACT FROM AUTHOR]

We present near-infrared broad-bandJHK′ images of the southern massive star-forming region G333.6−0.2. The slope of theK-luminosity function towards the regionis considered to be equivalent to that expected for main-sequence stars in the solar neighbourhood. Point sources with their (H− K) colour greater than 1 are more likely to be located in extended emission and it is suggested that these objects are physically associated with the H iiregion. [ABSTRACT FROM AUTHOR]

Examines the polarimetry of the southern massive star-forming region G333.6-0.2. Result of the spectropolarimetry measurements on nebula; Indications of the model fitting of spectra; Analysis of the absorptive polarization angle; Probability of the magnetic field configuration in polarization.