2011A&A...531A..88U


Query : 2011A&A...531A..88U

2011A&A...531A..88U - Astronomy and Astrophysics, volume 531A, 88-88 (2011/7-1)

The evolutionary state of Miras with changing pulsation periods.

UTTENTHALER S., VAN STIPHOUT K., VOET K., VAN WINCKEL H., VAN ECK S., JORISSEN A., KERSCHBAUM F., RASKIN G., PRINS S., PESSEMIER W., WAELKENS C., FREMAT Y., HENSBERGE H., DUMORTIER L. and LEHMANN H.

Abstract (from CDS):

Miras are long-period variables thought to be in the asymptotic giant branch (AGB) phase of evolution. In about one percent of known Miras, the pulsation period is changing. It has been speculated that this changing period is the consequence of a recent thermal pulse in these stars. We aim to clarify the evolutionary state of these stars, and to determine in particular whether or not they are in the thermally-pulsing (TP-)AGB phase. One important piece of information that has been neglected so far when determining the evolutionary state is the presence of the radio-active s-process element technetium (Tc). We obtained high-resolution, high signal-to-noise-ratio optical spectra of a dozen prominent Mira variables with changing pulsation period to search for this indicator of TPs and dredge-up. We also use the spectra to measure lithium (Li) abundances. Furthermore, we establish the evolutionary states of our sample stars by means of their present-day periods and luminosities. Among the twelve sample stars observed in this programme, five were found to show absorption lines of Tc. BH Cru is found to be a carbon-star, its period increase in the past decades possibly having stopped by now. We report a possible switch in the pulsation mode of T UMi from Mira-like to semi-regular variability in the past two years. R Nor, on the other hand, is probably a fairly massive AGB star, which could be true for all meandering Miras. Finally, we assign RU Vul to the metal-poor thick disk with properties very similar to the short-period, metal-poor Miras. We conclude that there is no clear correlation between period change class and Tc presence. The stars that are most likely to have experienced a recent TP are BH Cru and R Hya, although their rates of period change are quite different.

Abstract Copyright:

Journal keyword(s): stars: AGB and post-AGB - stars: oscillations - stars: evolution - stars: abundances

VizieR on-line data: <Available at CDS (J/A+A/531/A88): stars.dat sp/*>

Simbad objects: 25

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Number of rows : 25
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 6367 1
2 V* Y Per C* 03 27 42.3911607264 +44 10 36.486741684   11.89 9.19 8.78   C5,3e_Ba5 99 0
3 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 16147 1
4 V* S Ori Mi* 05 29 00.8923286472 -04 41 32.762469480   10.44 7.20     M6.5-7.5e 194 0
5 V* Z Tau S* 05 52 24.8532067728 +15 47 43.764061776     10.11 13.87   S7.51e 53 0
6 V* S Sex Mi* 10 34 56.0418882216 -00 20 33.473845032   11.63 8.20     M4-5e 56 0
7 V* BH Cru C* 12 16 16.7900401416 -56 17 09.626993196   10.60 7.96     C8,2 75 1
8 V* TT Cen S* 13 19 35.0158771776 -60 46 46.295369400     11.50     SC5:/8+ 52 0
9 V* R Hya Mi* 13 29 42.7818674 -23 16 52.774679 7.26 6.58 4.97 2.27 -0.15 M6-9e 473 0
10 V* T UMi Mi* 13 34 41.0716584144 +73 25 53.083879752   12.54 11.46     M6e 93 0
11 V* W Hya Mi* 13 49 02.0018313132 -28 22 03.532006894   8.97 7.70     M7.5-9e 623 0
12 * alf Boo RG* 14 15 39.67207 +19 10 56.6730 2.46 1.18 -0.05 -1.03 -1.68 K1.5IIIFe-0.5 2232 0
13 V* R Cen Mi* 14 16 34.3193427192 -59 54 49.294904112   9.65 7.55 4.45 1.37 M4-6e 133 0
14 V* R Nor Mi* 15 35 57.3542919 -49 30 28.681746   10.27 8.806 10.86   M3-7 74 0
15 V* S Her S* 16 51 53.9188877832 +14 56 30.763623732   9.69 6.40     M4-7.5Se 132 0
16 V* W Dra Mi* 18 05 34.6341947904 +65 57 21.594044988     10.80     M3-4 66 0
17 V* T Her Mi* 18 09 06.2110690224 +31 01 16.203768384   10.03 6.80     M2.5-8e 132 0
18 V* V2652 Sgr Mi* 18 12 48.4973760768 -33 19 26.900223996           ~ 10 0
19 V* R Aql OH* 19 06 22.2510922392 +08 13 48.012661776 8.06 7.69 6.09     M6.5-9e 548 0
20 V* RS Cyg C* 20 13 23.6616874008 +38 43 44.470030872 13.26 9.36 6.50 4.38 2.82 C-N5.5 176 0
21 V* V441 Cyg S* 20 27 08.1147520512 +36 33 06.503128128   12.04 9.80     S4,6 46 0
22 V* RU Vul LP* 20 38 52.6874269680 +23 15 31.176869868   10.86 9.18     M4e 43 1
23 V* T Cep Mi* 21 09 31.7834766408 +68 29 27.231070884 9.15 8.82 7.33     M6-9e 373 0
24 V* LX Cyg C* 21 55 57.0262652688 +48 20 52.522680876   13.22 10.49     C 36 1
25 NAME Galactic Bulge reg ~ ~           ~ 3894 0

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2022.08.07-20:52:01

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