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Universität zu Köln
Mathematisch-Naturwissenschaftliche Fakultät
Fachgruppe Physik

I. Physikalisches Institut

Research Projects

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  • spezzano


The doubly deuterated cyclopropenylidene, c-C3D2, has been detected for the first time in space toward the starless cores TMC-1C and L1544. The chemistry of deuterated molecules in space is connected to the early stages of star formation. Having more probes to study these processes is therefore crucial. Lines of the main species, c-C3H2, the singly deuterated c-C3HD, and the species with one 13C off of the principal axis of the molecule, c-H13CC2H, have also been detected. The lines of c-C3D2 have been observed with high signal-to-noise ratio, better than 7.5 sigma in TMC-1C and 9 sigma in L1544. The c-C3D2/ c-C3H2 ratio is found to be around 1% in both sources. The chemistry that leads to the formation of c-C3D2 has been studied. The observed abundances of c-C3D2 can be explained solely by gas-phase processes, supporting the idea that c-C3H2 is an excellent probe of gas-phase deuteration. ...more




{IRAM 30m telescope}

Recent Results

Lines of the isotopologues of c-C3H2 have been detected in both sources with very high signal-to-noise ratio. In addition to the observation of two lines of c-C3H2, one line of c-H13CC2H, two lines of c-C3HD, and three lines of c-C3D2 were also detected in both TMC-1C and L1544. This first interstellar detection of c-C3D2 is validated by the following reasons: -we detected all favorable transitions of c-C3D2 available in the covered frequency range; - the rest frequencies employed have laboratory accuracy, and in both sources the line shapes and velocities are in agreement with each other and with those observed for more abundant isotopologues; -the intensities of the c-C3D2 lines are consistent with what is expected from the deuteration of the ring in these sources, i.e. c-C3H2/c-C3HD is consistent with c-C3HD/c-C3D2.
Spectra of all isotopic species of c-C3H2 observed towards the starless core TMC-1C
Spectra of all isotopic species of c-C3H2 observed towards the starless core L1544


  • Interstellar Detection of c-C3D2
    Silvia Spezzano, Sandra Brünken, Peter Schilke, Paola Caselli, Karl M. Menten, Luca Bizzocchi, Sandra Trevino-Morales, Yuri Aikawa, Stephan Schlemmer
    The Astrophysical Journal 769 L19 (2013)


  • Silvia Spezzano was supported by the International Max Planck Research School (IMPRS) for Astronomy and Astrophysics
  • Funding by SFB 956.