- Names
-
- O. Poch
- I. Istiqomah
- E. Quirico
- P. Beck
- B. Schmitt
- P. Theulé
- A. Faure
- P. Hily-Blant
- L. Bonal
- A. Raponi
- M. Ciarniello
- B. Rousseau
- S. Potin
- O. Brissaud
- L. Flandinet
- G. Filacchione
- A. Pommerol
- N. Thomas
- D. Kappel
- V. Mennella
- L. Moroz
- V. Vinogradoff
- G. Arnold
- S. Erard
- D. Bockelée-Morvan
- C. Leyrat
- F. Capaccioni
- M. C. De Sanctis
- A. Longobardo
- F. Mancarella
- E. Palomba
- F. Tosi
- Title
- Ammonium salts are a reservoir of nitrogen on a cometary nucleus and possibly on some asteroids
- Abstract
- The measured nitrogen-to-carbon ratio in comets is lower than for the Sun, a discrepancy which could be alleviated if there is an unknown reservoir of nitrogen in comets. The nucleus of comet 67P/Churyumov-Gerasimenko exhibits an unidentified broad spectral reflectance feature around 3.2 µm, which is ubiquitous across its surface. Based on laboratory experiments, we attribute this absorption band to ammonium salts mixed with dust on the surface. The depth of the band indicates that semi-volatile ammonium salts are a substantial reservoir of nitrogen in the comet, potentially dominating over refractory organic matter and more volatile species. Similar absorption features appear in the spectra of some asteroids, implying a compositional link between asteroids, comets and the parent interstellar cloud.
- Keywords
- spectroscopy, grating spectrometer, gonio radiometer, bidirectional reflection, bidirectional reflectance spectra, near-IR, molecular solid, organic matter, ice, water ice, ammonium salts, ammonium formate, ammonium citrate, ammonium chloride, ammonium carbamate, ammonium sulfate, lactic acid, pyrrhotite, 67P/Churyumov-Gerasimenko, comet 67P, Themis, Cybele, Europa, Himalia, Bononia, Jupiter Trojans, Ceres, asteroids, comets, Solar System
- Content
- numerical model, sample, spectral data, experimental physics, planetary sciences, chemistry, remote sensing
- Document type
- article
- Publication state
- published
- Comments
- None
- Experiment/Spectra
-
- Vis-NIR bidirectional reflection spectrum of graphite powder at 296 K
- Vis-NIR bidirectional reflection spectrum of ammonium sulfate (67 wt%) mixed with graphite powder at 296 K
- Vis-NIR bidirectional reflection spectrum of ammonium formate (67 wt%) mixed with graphite powder at 296 K
- Vis-NIR bidirectional reflection spectrum of ammonium chloride (67 wt%) mixed with graphite powder at 296 K
- Vis-NIR bidirectional reflection spectrum of pyrrhotite sub-micrometer size grains in a sublimate residue at 173 K
- Vis-NIR bidirectional reflection spectrum of ammonium chloride (9 wt%) mixed with pyrrhotite sub-micrometer size grains in a sublimate residue at 173 K
- Vis-NIR bidirectional reflection spectrum of ammonium sulfate (9 wt%) mixed with pyrrhotite sub-micrometer size grains in a sublimate residue at 173 K
- Vis-NIR bidirectional reflection spectrum of ammonium sulfate (23 wt%) mixed with pyrrhotite sub-micrometer size grains in a sublimate residue at 173 K
- Vis-NIR bidirectional reflection spectrum of ammonium formate (17 wt%) mixed with pyrrhotite sub-micrometer size grains in a sublimate residue at 173 K
- Vis-NIR bidirectional reflection spectrum of ammonium formate (17 wt%) mixed with pyrrhotite sub-micrometer size grains in a sublimate residue at 173 K (duplicate)
- Vis-NIR bidirectional reflection spectrum of ammonium carbamate (17 wt%) mixed with pyrrhotite sub-micrometer size grains in a sublimate residue at 173 K
- Vis-NIR bidirectional reflection spectrum of ammonium citrate (23 wt%) mixed with pyrrhotite sub-micrometer size grains in a sublimate residue at 173 K