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The age of dense interstellar cloud cores, where stars and planets form, is a crucial parameter in star formation and difficult to measure. Some models predict rapid collapse, whereas others predict timescales of more than one million years (ref. 3). One possible approach to determining the age is through chemical changes as cloud contraction occurs, in(More)
Using the Submillimeter Array we have detected the J = 3 − 2 and 2 − 1 rotational transitions from within the first vibrationally excited state of CO toward the extreme carbon star IRC+10216 (CW Leo). The emission remains spatially unresolved with an angular resolution of ∼ 2 ′′ and, given that the lines originate from energy levels that are ∼ 3100 K above(More)
We present highly accurate laboratory measurements on the pure rotational spectrum of doubly deuterated water, D2O, in selected frequency regions from 10 GHz up to 2.7 THz. Around 140 rotational transitions in both the vibrational ground and first excited bending states (upsilon2=0,1) were measured in total, involving energy levels with unexcelled high J(More)
We present a clear detection of CH 2 in absorption towards the molecular cloud complexes Sagittarius B2 and W49 N using the ISO Long Wavelength Spectrometer. These observations represent the first detection of its low excitation rotational lines in the interstellar medium. Towards Sagittarius B2, we detect both ortho and para transitions allowing a(More)
Protonation of methane (CH4), a rather rigid molecule well described by quantum mechanics, produces CH5(+), a prototypical floppy molecule that has eluded definitive spectroscopic description. Experimental measurement of high-resolution spectra of pure CH5(+) samples poses a formidable challenge. By applying two types of action spectroscopy predicated on(More)
We report the detection of direct ℓ-type transitions towards the proto-planetary nebula CRL 618 during a study of vibrationally excited carbon chains. ∆J = 0 transitions of HCN in its first excited bending mode v 2 = 1 were detected in absorption against the continuum of the central H ii region making use of the Effelsberg 100 m telescope and the Very Large(More)
A spectral-line survey of IRC+10216 in the 345 GHz band has been undertaken with the Submil-limeter Array. Although not yet completed, it has already yielded a fairly large sample of narrow molecular emission lines with line-widths indicating expansion velocities of ∼4 km s −1 , less than 3 times the well-known value of the terminal expansion velocity (14.5(More)
The rotational spectrum of the molecular negative ion CN(-) has been detected in the laboratory at high resolution. The four lowest transitions were observed in a low pressure glow discharge through C(2)N(2) and N(2). Conclusive evidence for the identification was provided by well-resolved nitrogen quadrupole hyperfine structure in the lowest rotational(More)
The submillimeter-wave rotational spectra of CO(+), (13)CO(+) and C(18)O(+) in the v = 0 and 1 vibrational states were measured through a hollow cathode dc discharge in a cryogenic cell cooled to liquid nitrogen temperature. In addition, a few transitions of the main isotopic species have been measured between 1.1 and 1.3 THz. An updated isotopically(More)