[en] High-resolution spectra of the CN B[SUP]2[/SUP] Sigma[SUP]+[/SUP]-X[SUP]2[/SUP] Sigma[SUP]+[/SUP] (0,0) band at 390 nanometers yield isotopic ratios for comets C/1995 O1 (Hale-Bopp) and C/2000 WM1 (LINEAR) as follows: 165 +/- 40 and 115 +/- 20 for [SUP]12[/SUP]C/[SUP]13[/SUP]C, 140 +/- 35 and 140 +/- 30 for [SUP]14[/SUP]N/[SUP]15[/SUP]N. Our N isotopic measurements are lower than the terrestrial [SUP]14[/SUP]N/[SUP]15[/SUP]N = 272 and the ratio for Hale-Bopp from measurements of HCN, the presumed parent species of CN. This isotopic anomaly suggests the existence of other parent(s) of CN, with an even lower N isotopic ratio. Organic compounds like those found in interplanetary dust particles are good candidates.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Arpigny, Claude ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO)
Jehin, Emmanuel ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image
Manfroid, Jean ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO)
Hutsemekers, Damien ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS)
Schulz, Rita; ESA/RSSD, ESTEC, Post Office Box 299, NL-2200 AG Noordwijk, Netherlands.
Stüwe, J. A.; Leiden Observatory, NL-2300 RA Leiden, Netherlands.
Zucconi, Jean-Marc; Observatoire de Besançon, F25010 Besançon Cedex, France.
Ilyin, Ilya; Astronomy Division, Post Office Box 3000, FIN 90014 University of Oulu, Finland.
Language :
English
Title :
Anomalous Nitrogen Isotope Ratio in Comets
Publication date :
01 September 2003
Journal title :
Science
ISSN :
0036-8075
eISSN :
1095-9203
Publisher :
American Association for the Advancement of Science, Washington, United States - District of Columbia
Material and methods are available as supporting material on Science online.
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Based on observations of comet Hale-Bopp made with the Nordic Optical Telescope, La Palma, Canary Islands, Spain. The WM1 observations were carried out at the ESO. We thank the director of the ESO VLT for approving our program for Director's Discretionary Time (ESO DDT 268.C-5570). We also thank the observatory staff astronomers who have carried out these observations. The authors are grateful to J. Aléon for useful discussions. C.A., J.M., and D.H. acknowledge financial support from the Belgian NFSR.
