2016A&A...591A..89M


Query : 2016A&A...591A..89M

2016A&A...591A..89M - Astronomy and Astrophysics, volume 591A, 89-89 (2016/7-1)

Chromospheric activity and evolutionary age of the Sun and four solar twins.

MITTAG M., SCHRODER K.-P., HEMPELMANN A., GONZALEZ-PEREZ J.N. and SCHMITT J.H.M.M.

Abstract (from CDS):

Aims. The activity levels of the solar-twin candidates HD 101364 and HD 197027 are measured and compared with the Sun, the known solar twin 18 Sco, and the solar-like star 51 Peg. Furthermore, the absolute ages of these five objects are estimated from their positions in the HR diagram and the evolutionary (relative) age compared with their activity levels.
Methods. To represent the activity level of these stars, the Mount Wilson S-indices were used. To obtain consistent ages and evolutionary advance on the main sequence, we used evolutionary tracks calculated with the Cambridge Stellar Evolution Code.
Results. From our spectroscopic observations of HD 101364 and HD 197027 and based on the established calibration procedures, the respective Mount Wilson S-indices are determined. We find that the chromospheric activity of both stars is comparable with the present activity level of the Sun and that of 18 Sco, at least for the period in consideration. Furthermore, the absolute age of HD 101364, HD 197027, 51 Peg, and 18 Sco are found to be 7.2, 7.1, 6.1, and 5.1Gyr, respectively.
Conclusions. With the exception of 51 Peg, which has a significantly higher metallicity and a mass higher by about 10% than the Sun, the present Sun and its twins compare relatively well in their activity levels, even though the other twins are somewhat older. Even though 51 Peg has a similar age of 6.1Gyr, this star is significantly less active. Only when we compare it on a relative age scale (which is about 20% shorter for 51 Peg than for the Sun in absolute terms) and use the higher-than-present long-term SMWO average of 0.18 for the Sun, does the S-index show a good correlation with evolutionary (relative) age. This shows that in the search for a suitably similar solar twin, the relative main-sequence age matters for obtaining a comparable activity level.

Abstract Copyright: © ESO, 2016

Journal keyword(s): stars: activity - stars: chromospheres - stars: late-type

Simbad objects: 53

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Number of rows : 53
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 * 44 And PM* 01 10 18.7404097416 +42 04 53.309986932   6.249 5.665     F8V 178 0
2 * tau Cet PM* 01 44 04.0831371922 -15 56 14.927607677 4.43 4.22 3.50 2.88 2.41 G8V 1197 1
3 * 64 Cet PM* 02 11 21.0787585632 +08 34 11.305868808   6.189 5.623 6.81   G0IV 117 0
4 HD 16673 SB* 02 40 12.4210104672 -09 27 10.335330216   6.294 5.790     F8VFe-0.4 233 0
5 HD 17925 RS* 02 52 32.1281856011 -12 46 10.968056223 7.48 6.91 6.05 5.34 4.89 K1V 496 0
6 * iot Per PM* 03 09 04.0193012009 +49 36 47.802053343 4.76 4.64   3.7   G0V 529 0
7 * eps Eri BY* 03 32 55.8444911587 -09 27 29.739493865 5.19 4.61 3.73 3.00 2.54 K2V 1837 1
8 HD 22072 PM* 03 34 08.3780792889 +17 49 58.182313637   7.06 6.16 5.6   K0.5IVFe-1 98 0
9 * del Eri * 03 43 14.9005379551 -09 45 48.210955899 5.13 4.46 3.54 2.82 2.32 K0+IV 576 0
10 * 50 Per RS* 04 08 36.6171573432 +38 02 23.058806100 7.78 5.97   5.2   F8V 213 0
11 HD 26923 PM* 04 15 28.8004060272 +06 11 12.698572488 6.910 6.860   5.9   G0IV 206 0
12 * 58 Eri BY* 04 47 36.2917029384 -16 56 04.040472552   6.14 5.50     G2.5IV-V 408 0
13 * m Tau ** 05 07 27.0055682766 +18 38 42.179768546 5.79 5.65   4.5   G4V 275 0
14 * 111 Tau BY* 05 24 25.4632701888 +17 23 00.726415944   5.52   4.7   F8V 327 0
15 HD 37394 BY* 05 41 20.3356800431 +53 28 51.808818686 7.58 7.07 6.23 5.54 5.11 K1 315 0
16 * chi01 Ori RS* 05 54 22.9829893 +20 16 34.222038 5.08 5.00 4.40 3.90 3.59 G0V 831 0
17 HD 41330 PM* 06 06 08.5350860383 +35 23 15.860287421   6.72   5.8   G0V 121 0
18 HD 42807 RS* 06 13 12.5028624208 +10 37 37.712484445   7.12   6.0   G5V 224 0
19 HD 43587 SB* 06 17 16.1297031648 +05 05 59.904745548 6.400 6.290   5.3   G0V 230 0
20 HD 45067 PM* 06 25 16.5462760045 -00 56 45.178443827   6.43 5.90     F9V 190 0
21 * alf CMi SB* 07 39 18.11950 +05 13 29.9552 0.82 0.79 0.37 -0.05 -0.28 F5IV-V+DQZ 1836 0
22 * pi.01 UMa BY* 08 39 11.7046112880 +65 01 15.263122512 6.33 6.26 5.64 5.12 4.79 G0.5V 548 0
23 * 5 LMi PM* 08 50 32.2228174512 +33 17 06.195898140   6.738 6.210     F7Vs 165 0
24 * 54 Cnc PM* 08 51 01.4644114368 +15 21 02.364115536   7.017 6.361     G1V 63 0
25 HD 82443 BY* 09 32 43.7594578944 +26 59 18.706023348   7.78   6.6   G9V(k) 237 1
26 HD 89744 PM* 10 22 10.5618854376 +41 13 46.309698444       5.4   F7V 320 1
27 HD 95735 Er* 11 03 20.1948195942 +35 58 11.576182057 10.030 8.960 7.520 5.99 4.79 M2+V 682 0
28 HD 97334 BY* 11 12 32.3503039560 +35 48 50.688978228   7.02   6.0   G2 271 0
29 * 89 Leo PM* 11 34 21.9489030480 +03 03 36.593787600   6.23   5.5   F5.5V 153 0
30 HD 101364 PM* 11 40 28.4839370424 +69 00 30.597806088   9.32 8.67     G5 69 0
31 * 61 UMa PM* 11 41 03.0162706212 +34 12 05.881605449 6.31 6.08 5.34 4.73 4.38 G8V 596 0
32 HD 103072 PM* 11 52 08.3372221698 +18 45 18.655396674   9.32   7.8   K2V 41 0
33 HD 106516 SB* 12 15 10.55731 -10 18 44.6354 6.44 6.57 6.11     F9VFe-1.7CH-0.7 404 0
34 * alf Com A PM* 13 09 59.285492 +17 31 45.85645   5.25 4.80     F5V 240 0
35 HD 115043 PM* 13 13 37.0081725552 +56 42 29.759356008   7.423 6.813     G1Va 250 0
36 * e Vir PM* 13 16 46.5148594512 +09 25 26.960139646   5.81   4.8   G0V 534 1
37 * 61 Vir PM* 13 18 24.3139864471 -18 18 40.297748582 5.710 5.440 4.740     G6.5V 643 1
38 * 14 Boo ** 14 14 05.1793499304 +12 57 33.996726108   6.08   5.2   F8V 167 0
39 * iot Vir PM* 14 16 00.8695049 -06 00 01.963348 4.64 4.60 4.08     F7III 348 0
40 V* EK Dra BY* 14 39 00.2104038120 +64 17 29.979649860   8.243 7.604     G1.5V 424 0
41 * ksi Boo A PM* 14 51 23.3884659504 +19 06 01.619801424   5.40 4.675     G7Ve 520 0
42 * eta CrB A * 15 23 12.230856 +30 17 17.56212   6.123 5.577     G2V 228 0
43 * chi Her PM* 15 52 40.5410491705 +42 27 05.462878877 5.19 5.19 4.62 4.14 3.82 F8VFe-2Hdel-1 492 0
44 * 18 Sco PM* 16 15 37.2702755653 -08 22 09.982125430   6.15 5.50     G2Va 556 0
45 HD 158614 SB* 17 30 23.79699 -01 03 46.4882 6.34 6.03 5.31 5.52   G9-IV-VHdel1 288 0
46 HD 159332 PM* 17 33 22.8242819328 +19 15 24.040331928   6.130 5.648     F4V 134 0
47 * b Aql PM* 19 24 58.1999714302 +11 56 39.888480530 6.35 5.93   4.7   G7IVHdel1 476 0
48 HD 190360 PM* 20 03 37.4050868074 +29 53 48.492435887   6.44   5.2   G7IV-V 425 1
49 HD 197027 PM* 20 41 54.6335853576 -27 12 57.415436208   9.80 9.15     G3V 66 0
50 * 61 Cyg A BY* 21 06 53.9395895022 +38 44 57.902349973 7.50 6.39 5.21 4.19 3.54 K5V 1005 0
51 * 15 Peg PM* 21 52 29.9168018496 +28 47 36.750679764 5.82 5.95 5.53     F2V 234 0
52 * sig Peg PM* 22 52 24.0744611045 +09 50 08.394417666   5.64   4.9   F6V 272 0
53 * 51 Peg PM* 22 57 27.9804852576 +20 46 07.797040104 6.39 6.16 5.46 4.97 4.61 G2IV 1133 1

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2023.01.27-12:57:47

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