2005A&A...431..329L


Query : 2005A&A...431..329L

2005A&A...431..329L - Astronomy and Astrophysics, volume 431, 329-338 (2005/2-3)

Fine structure of the chromospheric activity in Solar-type stars - The Hα line.

LYRA W. and PORTO DE MELLO G.F.

Abstract (from CDS):

A calibration of Hα as both a chromospheric diagnostic and an age indicator is presented, complementing the works previously done on this subject (Herbig, 1985ApJ...289..269H]; Pasquini & Pallavicini, 1991A&A...251..199P). The chromospheric diagnostic was built with a statistically significant sample, covering nine years of observations, and including 175 solar neighborhood stars. Regarding the age indicator, the presence of stars for which very accurate ages are determined, such as those belonging to clusters and kinematic groups, lends confidence to our analysis. We also investigate the possibility that stars of the same age might have gone through different tracks of chromospheric decay, identifying - within the same age range - effects of metallicity and mass. These parameters, however, as well as age, seem to be significant only for dwarf stars, losing their meaning when we analyze stars in the subgiant branch. This result suggests that, in these evolved stars, the emission mechanism cannot be magnetohydrodynamical in nature, in agreement with recent models (Fawzy et al., 2002A&A...386..994F, and references therein). The Sun is found to be a typical star in its Hα chromospheric flux, for its age, mass and metallicity. As a byproduct of this work, we developed an automatic method to determine temperatures from the wings of Hα, which means the suppression of the error inherent to the visual procedure used in the literature.

Abstract Copyright:

Journal keyword(s): stars: activity - stars: atmospheres - stars: chromospheres - techniques: spectroscopic - Galaxy: solar neighbourhood - line: formation

Simbad objects: 34

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Number of rows : 34
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 * 9 Cet BY* 00 22 51.7884553555 -12 12 33.969921319 7.29 7.05 6.39     G2.5V 487 0
2 * bet Hyi PM* 00 25 45.07036 -77 15 15.2860 3.52 3.41 2.79 2.28 1.94 G0V 590 0
3 * tau Cet PM* 01 44 04.0831371922 -15 56 14.927607677 4.43 4.22 3.50 2.88 2.41 G8V 1249 1
4 V* EZ Cet BY* 01 49 23.3488631760 -10 42 13.083858540 7.49 7.386 6.754 6.392 6.04 G3V 172 0
5 * zet01 Ret PM* 03 17 46.1634549490 -62 34 31.152456644 6.24 6.18 5.54 5.00 4.66 G2.5VHdel1 294 0
6 * zet02 Ret ** 03 18 12.8188824117 -62 30 22.904711032   5.814 5.228     G1V 362 0
7 Cl Melotte 22 OpC 03 46 24.2 +24 06 50           ~ 3411 0
8 HD 282975 Y*O 03 46 37.6798897555 +23 47 15.790663787 11.533 10.8 10.0   9.43 G6V 86 0
9 BD+23 527 Er* 03 46 53.7464379963 +23 35 00.796614675 11.607 11.1 10.6   9.85 G0V 92 0
10 V* V1046 Tau Er* 03 46 54.9177933516 +24 47 46.825737223   11.5 10.6   9.79 G5 80 0
11 HD 26913 BY* 04 15 25.7871375264 +06 11 58.751401236 7.790 7.580 6.920 6.554 6.195 G8V 217 0
12 HD 26923 PM* 04 15 28.8004060272 +06 11 12.698572488 6.910 6.860   5.9   G0IV 213 0
13 HD 27685 SB* 04 22 44.7200401380 +16 47 27.158550607 8.730 8.495 7.821 7.456 7.104 G4V 159 0
14 HD 27859 BY* 04 24 28.3269703416 +16 53 10.202918748   8.382 7.790     G2V 223 0
15 HD 28099 BY* 04 26 40.1217122952 +16 44 48.885808416 8.98 8.78 8.12 7.56 7.23 G2+V 417 0
16 HD 28344 BY* 04 28 48.2984108040 +17 17 07.685984400 8.57 8.456 7.837 7.498 7.180 G2V 281 0
17 Cl Melotte 25 OpC 04 29 47.3 +16 56 53           ~ 3050 0
18 HD 28992 BY* 04 34 35.3100676992 +15 30 16.642906992   8.530 7.898 7.556 7.226 ~ 208 0
19 HD 32147 PM* 05 00 48.9993452248 -05 45 13.224327192 8.27 7.27 6.21 5.36 4.87 K3+V 457 1
20 * chi01 Ori RS* 05 54 22.9829893 +20 16 34.222038 5.08 5.00 4.40 3.90 3.59 G0V 848 0
21 V* V1386 Ori PM* 06 06 40.4780487600 +15 32 31.578871020 8.016 7.565   6.2   K0V 166 0
22 HD 76151 PM* 08 54 17.9470964696 -05 26 04.054298491 6.89 6.67 6.00     G2V 530 0
23 * alf Cen A SB* 14 39 36.49400 -60 50 02.3737 0.96 0.72 0.01     G2V 1270 1
24 NAME Ursa Major Cluster ClG 15 08.8 +67 07           ~ 409 0
25 * nu.02 Lup PM* 15 21 48.1499105161 -48 19 03.469906910 6.35 6.30 5.65     G3/5V 292 1
26 * 18 Sco PM* 16 15 37.2702755653 -08 22 09.982125430   6.15 5.50     G2Va 599 0
27 HD 147513 PM* 16 24 01.2911377368 -39 11 34.729913940 6.17 6.02 5.376     G5V 347 1
28 HD 154931 PM* 17 08 21.4135278528 +04 25 28.170498036   7.87   6.9   G0V 68 0
29 HD 161612 PM* 17 47 57.5496960470 -34 01 07.948899796   7.91 7.20     G8V 120 0
30 HD 165185 PM* 18 06 23.7195191736 -36 01 11.230597272 6.64 6.57 5.95 5.58   G1V 167 0
31 * b Aql PM* 19 24 58.1999714302 +11 56 39.888480530 6.35 5.93   4.7   G7IVHdel1 487 0
32 * del Pav PM* 20 08 43.6088716052 -66 10 55.442769229 4.78 4.32 3.56 2.95 2.61 G8IV 389 0
33 HD 194640 PM* 20 27 44.2430551737 -30 52 04.244023567   7.35 6.62     G8V 111 0
34 * phi02 Pav PM* 20 40 02.6374808954 -60 32 56.018592211   5.63 5.121     G0VFe-0.8CH-0.5 174 1

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