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Ultra-high spectral resolution observations of time-varying interstellar absorption towards κ Vel are reported, using the Ultra-High Resolution Facility on the Anglo-Australian Telescope. Detections of interstellar Ca i, Ca ii, K i, Na i and CH are obtained, whilst an upper limit on the column density is reported for C2. The results show continued increases in column densities of K i and Ca i since observations ∼4 yr earlier, as the transverse motion of the star carried it ∼10 au perpendicular to the line of sight. Line profile models are fitted to the spectra and two main narrow components (A and B) are identified for all species except CH. The column density N(K i) is found to have increased by 82+ 10− 9 per cent between 1994 and 2006, whilst N(Ca i) is found to have increased by 32 ± 5 per cent over the shorter period of 2002–2006. The line widths are used to constrain the kinetic temperature to Tk, A < 671+ 18− 17 K and Tk, B < 114+ 15− 14 K. Electron densities are determined from the Ca i/Ca ii ratio, which in turn place lower limits on the total number density of nA ≳ 7 × 103 cm−3 and nB ≳ 2 × 104 cm−3. Calcium depletions are estimated from the Ca i/K i ratio. Comparison with the chemical models of Bell et al. confirms the high number density, with n = 5 × 104 cm−3 for the best-fitting model. The first measurements of diffuse interstellar bands (DIBs) towards this star are made at two epochs, but only an upper limit of ≲ 40 per cent is placed on their variation over ∼9 yr. The DIBs are unusually weak for the measured E(B − V) and appear to exhibit similar behaviour to that seen in Orion. The ratio of equivalent widths of the λ5780 to λ5797 DIBs is amongst the highest known, which may indicate that the carrier of λ5797 is more sensitive to ultraviolet radiation than to local density. [ABSTRACT FROM AUTHOR]

ABSTRACT The first detection of the C60 (Buckminsterfullerene) molecule in massive embedded young stellar objects (YSOs) is reported. Observations with the Spitzer Infrared Spectrograph reveal the presence of C60 in YSOs ISOGAL-P J174639.6−284126 and SSTGC 372630 in the Central Molecular Zone in the Galactic Centre and in a YSO candidate, 2MASS J06314796+0419381, in the Rosette nebula. The first detection of C60 in a Herbig Ae/Be star, HD 97300, is also reported. These observations extend the range of astrophysical environments in which C60 is found to YSOs and a pre-main-sequence star. C60 excitation and formation mechanisms are discussed in the context of these results, together with its presence and processes in post-asymptotic giant branch objects such as HR 4049. [ABSTRACT FROM AUTHOR]