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Ammonium salts are a reservoir of nitrogen on a cometary nucleus and possibly on some asteroids.

Authors :
Poch O
Istiqomah I
Quirico E
Beck P
Schmitt B
Theulé P
Faure A
Hily-Blant P
Bonal L
Raponi A
Ciarniello M
Rousseau B
Potin S
Brissaud O
Flandinet L
Filacchione G
Pommerol A
Thomas N
Kappel D
Mennella V
Moroz L
Vinogradoff V
Arnold G
Erard S
Bockelée-Morvan D
Leyrat C
Capaccioni F
De Sanctis MC
Longobardo A
Mancarella F
Palomba E
Tosi F
Source :
Science (New York, N.Y.) [Science] 2020 Mar 13; Vol. 367 (6483).
Publication Year :
2020

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 micrometers, which is ubiquitous across its surface. On the basis of laboratory experiments, we attribute this absorption band to ammonium salts mixed with dust on the surface. The depth of the band indicates that semivolatile 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.<br /> (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Details

Language :
English
ISSN :
1095-9203
Volume :
367
Issue :
6483
Database :
MEDLINE
Journal :
Science (New York, N.Y.)
Publication Type :
Academic Journal
Accession number :
32165559
Full Text :
https://doi.org/10.1126/science.aaw7462