1999ApJ...513L..87S


Query : 1999ApJ...513L..87S

1999ApJ...513L..87S - Astrophys. J., 513, L87-L90 (1999/March-1)

The SiC problem: astronomical and meteoritic evidence.

SPECK A.K., HOFMEISTER A.M. and BARLOW M.J.

Abstract (from CDS):

Presolar grains of silicon carbide, found in meteorites and interpreted as having had an origin around carbon stars from their isotopic composition, have all been found to be of the β-SiC polytype. Yet, to date, fits to the 11.3 µm SiC emission band of carbon stars had been obtained only for α-SiC grains. We present thin-film infrared (IR) absorption spectra that were measured in a diamond-anvil cell for both the α- and β-polymorphs of synthetic SiC, and we compare the results with previously published spectra that were taken using the KBr matrix method. We find that our thin-film spectra have positions nearly identical to those obtained previously from finely ground samples in KBr. Hence, we show that this discrepancy has arisen from inappropriate ``KBr corrections'' having been made to laboratory spectra of SiC particles dispersed in KBr matrices. We refitted a sample of carbon star mid-IR spectra, using laboratory data with no KBr correction applied, and show that β-SiC grains fitted the observations while α-SiC grains did not. The discrepancy between meteoritic and astronomical identifications of the SiC type is therefore removed. This work shows that the diamond-anvil cell, thin-film method can be used to produce mineral spectra that are applicable to cosmic environments without further manipulation.

Abstract Copyright:

Journal keyword(s): Infrared: ISM: Lines and Bands - Infrared: Stars - Methods: Laboratory - Stars: Carbon

Simbad objects: 28

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Number of rows : 28
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 IRAS 02152+2822 C* 02 18 06.0449013192 +28 36 45.346478742           C-rich 49 0
2 V* R For C* 02 29 15.3081251463 -26 05 55.647016467   12.94 7.50     C4,3e 185 0
3 RAFGL 341 C* 02 33 00.34296 +58 02 06.2340           C-rich 51 0
4 RAFGL 5076 C* 02 38 07.069 +54 35 16.23           C 17 0
5 IRAS 02408+5458 Mi* 02 44 25.2 +55 11 15           ~ 21 0
6 LEE 259 C* 03 26 29.5050382299 +47 31 48.463099623           N 170 0
7 RAFGL 5102 C* 03 48 19.3122107756 +44 42 06.210576191           C-rich 31 0
8 IRC +40070 C* 03 52 14.3521736066 +39 52 50.772229237       12.15   C-rich 42 0
9 V* R Lep C* 04 59 36.3480393629 -14 48 22.511432606 15.06 13.51 7.76 4.90 3.42 C7,6e 323 0
10 V* UU Aur C* 06 36 32.8375658812 +38 26 43.833646997   7.89 5.25 3.31 1.90 C-N5- 294 1
11 IRC +10216 C* 09 47 57.40632 +13 16 43.5648     10.96     C9,5e 2205 0
12 V* RW LMi C* 10 16 02.2834693816 +30 34 18.977096332       15.27   C4,3e 384 0
13 V* V Hya C* 10 51 37.2614060865 -21 15 00.339641553   12.23 6.80     C-N:6 344 0
14 WOS 31 s?r 11 58 10.9338870903 -63 24 46.737553010     15.7     M3 10 2
15 V* Y CVn C* 12 45 07.8257032577 +45 26 24.898861195 14.03 7.41 4.87 3.12 1.74 C-N5 466 0
16 RAFGL 2155 C* 18 26 05.83560 +23 28 46.6932         17.63 C-rich 80 0
17 Case 176 C* 18 42 24.8714797393 -02 17 27.091013289   16.56 13.49 15.53 10.79 C 71 0
18 V* V Aql C* 19 04 24.1548619887 -05 41 05.434251344   11.09 6.90     C-N5 207 0
19 IRC -10502 C* 19 20 18.1188934440 -08 02 12.080226785       13.22 10.59 C5,4e 69 0
20 RAFGL 2477 S* 19 56 48.4420056358 +30 44 02.609739938   17.9 14.8 14.1   M6SIII 54 1
21 RAFGL 2494 C* 20 01 09.0488458825 +40 55 39.036558501           C 65 0
22 V* V Cyg C* 20 41 18.2688237607 +48 08 28.886946369   14.05 7.70     C7,4eJ 297 0
23 RAFGL 2699 C* 21 04 14.5270005345 +53 21 04.761679777     15.40     C8,3e 41 0
24 RAFGL 5625S C* 21 33 22.795 +56 44 34.52           C 55 0
25 IRAS 21489+5301 C* 21 50 44.90 +53 15 27.9           C-rich 38 0
26 RAFGL 3068 C* 23 19 12.60744 +17 11 33.1332           C 257 0
27 RAFGL 3099 C* 23 28 17.1148783705 +10 54 37.400631176           C-rich 89 0
28 IRC +40540 C* 23 34 27.5215563443 +43 33 01.299562617     15.12     C8,3.5eJ 173 0

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2021.09.22-15:43:31

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