2004MNRAS.352..325Z


Query : 2004MNRAS.352..325Z

2004MNRAS.352..325Z - Mon. Not. R. Astron. Soc., 352, 325-337 (2004/July-3)

Period and chemical evolution of SC stars.

ZIJLSTRA A.A., BEDDING T.R., MARKWICK A.J., LOIDL-GAUTSCHY R., TABUR V., ALEXANDER K.D., JACOB A.P., KISS L.L., PRICE A., MATSUURA M. and MATTEI J.A.

Abstract (from CDS):

The SC and CS stars are thermal-pulsing asymptotic giant branch stars with a C/O ratio close to unity. Within this small group, the Mira variable BH Cru recently evolved from spectral type SC (showing ZrO bands) to CS (showing weak C2). Wavelet analysis shows that the spectral evolution was accompanied by a dramatic period increase, from 420 to 540 d, indicating an expanding radius. The pulsation amplitude also increased. Old photographic plates are used to establish that the period before 1940 was around 490 d. Chemical models indicate that the spectral changes were caused by a decrease in stellar temperature, related to the increasing radius. There is no evidence for a change in C/O ratio. The evolution in BH Cru is unlikely to be related to an ongoing thermal pulse. Periods of the other SC and CS stars, including nine new periods, are determined. A second SC star, LX Cyg, also shows evidence for a large increase in period, and one further star shows a period inconsistent with a previous determination. Mira periods may be intrinsically unstable for C/O ~ 1; possibly because of a feedback between the molecular opacities, pulsation amplitude, and period. LRS spectra of 6 SC stars suggest a feature at λ > 15 µm, which resembles one recently attributed to the iron-sulphide troilite. Chemical models predict a large abundance of FeS in SC stars, in agreement with the proposed association.

Abstract Copyright: 2004 RAS

Journal keyword(s): stars: AGB and post-AGB - stars: fundamental parameters - stars: individual: BH Cru

Simbad objects: 31

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Number of rows : 31
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 V* WZ Cas C* 00 01 15.8567946264 +60 21 19.025920224 8.77 9.47 7.13     C-N7III: 315 0
2 V* TY Cas Mi* 00 36 59.3979390720 +63 08 01.809743388     13.20 11.57   M8 51 0
3 V* W Cas C* 00 54 53.8485356496 +58 33 49.148976420   11.32 11.32 9.32   C9,1e 137 0
4 V* Y Per C* 03 27 42.3911607264 +44 10 36.486741684   11.89 9.19 8.78   C5,3e_Ba5 103 0
5 V* R Dor AB* 04 36 45.59127 -62 04 37.7974 7.84 6.98 5.40 2.71 -0.44 M8III:e 346 0
6 V* R Ori S* 04 59 00.5594811144 +08 07 49.719678420   13.06 9.05     SC5-8e 70 0
7 V* GP Ori S* 05 02 48.0655541832 +15 19 12.661687128   11.95 12.20     SC7/8 95 0
8 V* S Ori Mi* 05 29 00.8923286472 -04 41 32.762469480   10.44 7.20     M6.5-7.5e 201 0
9 V* FU Mon S* 06 22 23.8515787464 +03 25 27.887405916 16.86 12.36 9.06     S6.5/7.5 120 1
10 V* V372 Mon S* 06 41 26.1306263952 -04 35 45.776587524   12.69 9.81     SC7/7.5 36 0
11 V* R CMi S* 07 08 42.6121220544 +10 01 26.458092084   9.65 7.25     SC4-7/10e 161 0
12 V* UX Vol S* 08 46 17.3591620800 -71 02 20.263048908   13.45 9.02 8.33   SC 22 0
13 V* AM Car C* 10 14 29.3498567640 -60 43 28.016873796   13.40 10.69     C 19 0
14 V* BH Cru C* 12 16 16.7900401416 -56 17 09.626993196   10.60 7.96     C8,2 80 1
15 V* UY Cen S* 13 16 31.8299380416 -44 42 15.757651800 14.09 10.03 7.13     S6/8 86 0
16 V* TT Cen S* 13 19 35.0158771776 -60 46 46.295369400     11.50     SC5:/8+ 55 0
17 V* R Hya Mi* 13 29 42.7801586466 -23 16 52.751628992 7.26 6.58 4.97 2.27 -0.15 M6-9e 488 0
18 V* T UMi Mi* 13 34 41.0716584144 +73 25 53.083879752   12.54 11.46     M6e 96 0
19 V* AM Cen S* 13 47 17.6163269400 -53 21 25.926046632   11.50 9.20 8.40   SC 42 0
20 V* R Cen Mi* 14 16 34.3193427192 -59 54 49.294904112   9.65 7.55 4.45 1.37 M4-6e 137 0
21 V* VY Aps S* 16 00 53.6192844792 -74 28 52.929975864   12.48 9.17     SC 24 0
22 V* RR Her C* 16 04 13.4079117672 +50 29 56.991501888   11.32 8.80     SC5.5-C71e 82 0
23 V* LQ Ara S* 16 51 41.3243239008 -61 01 20.323482996   12.83 10.30     SC 18 0
24 V* V3832 Sgr S* 18 29 00.8099833248 -24 36 39.424933692           SC 8 0
25 V* VX Aql S* 19 00 09.6081225960 -01 34 56.720264268   15.23 12.20 9.19   SC5/8e 71 0
26 V* R Aql OH* 19 06 22.2510922392 +08 13 48.012661776 8.06 7.69 6.09     M6.5-9e 564 2
27 V* S Lyr S* 19 13 11.8046954880 +26 00 27.853438788       11.35   SC 74 0
28 V* CM Cyg S* 19 58 34.2531008880 +52 05 45.787293744   10.0   10.43   S4/6.5e 25 0
29 V* CY Cyg S* 20 46 50.2447266864 +46 03 06.930770400   10.82 11.00     SC2_Zr0 57 0
30 V* LX Cyg C* 21 55 57.0262652688 +48 20 52.522680876   13.22 10.49 10.52   C 39 1
31 V* RZ Peg Mi* 22 05 52.9706535288 +33 30 24.810555528   11.40 7.60 7.89   SC5-9/9-e 159 0

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