Maqola

Titanium Carbide Nanocrystals in Circumstellar Environments

Gert von HeldenDepartment of Molecular and Laser Physics, University of Nijmegen, Toernooiveld 1, NL-6525 ED Nijmegen, NetherlandsA. M.TielensSRON/Kapteyn Institute, University of Groningen, Landleven 12, NL-9700 AV Groningen, NetherlandsDeniz van HeijnsbergenDepartment of Molecular and Laser Physics, University of Nijmegen, Toernooiveld 1, NL-6525 ED Nijmegen, NetherlandsMichael A. DuncanDepartment of Chemistry, University of Georgia, Athens, GA 30602, USAS. HonyAstronomical Institute, University of Amsterdam, Kruislaan 403, NL-1098 SJ Amsterdam, NetherlandsL. B. F. M. WatersAstronomical Institute, University of Amsterdam, Kruislaan 403, NL-1098 SJ Amsterdam, NetherlandsGerard MeijerDepartment of Molecular and Laser Physics, University of Nijmegen, Toernooiveld 1, NL-6525 ED Nijmegen, Netherlands

2000en

ABI

Annotatsiya

Meteorites contain micrometer-sized graphite grains with embedded titanium carbide grains. Although isotopic analysis identifies asymptotic giant branch stars as the birth sites of these grains, there is no direct observational identification of these grains in astronomical sources. We report that infrared wavelength spectra of gas-phase titanium carbide nanocrystals derived in the laboratory show a prominent feature at a wavelength of 20.1 micrometers, which compares well to a similar feature in observed spectra of postasymptotic giant branch stars. It is concluded that titanium carbide forms during a short (approximately 100 years) phase of catastrophic mass loss (>0.001 solar masses per year) in dying, low-mass stars.

Hali tarjima qilinmagan

Identifikatorlar

DOI: 10.1126/science.288.5464.313

Iqtiboslar va manbalar

2 ta iqtibos0 ta foydalanilgan manba

Koʻrsatkichlar — AkademScholar