2018A&A...616A.154G


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.10CEST03:13:35

2018A&A...616A.154G - Astronomy and Astrophysics, volume 616A, 154-154 (2018/8-1)

Magnetic activity evolution on Sun-like stars.

GONDOIN P.

Abstract (from CDS):


Context. Characterising the time evolution of magnetic activity on Sun-like stars is important not only for stellar physics but also for determining the environment in which planets evolve.
Aims. In recent decades, many surveys of open clusters have produced extensive rotation periods measurements on Sun-like stars of different ages. The present study uses this information with the aim to improve the description of their magnetic activity evolution.
Methods. I present a method that infers the long-term evolution of Ca II chromospheric (R'HK) and X-ray coronal (LX) emission on solar mass stars by combining a best fit parametric model of their rotation evolution with empirical rotation-activity relationships.
Results. The inferred scenario reproduces the high chromospheric and coronal emission levels around R'HK~=10–4 and LX~=1030erg/s that are observed on pre-main sequence (PMS) stars. At the end of the PMS contraction phase around the age of ∼30Myr, the slowest rotating stars experience a rapid transition of their magnetic activity to more moderate levels around R'HK~=4x10–5 and L5~=1029erg/s. This transition occurs later on more rapidly rotating stars, up to an age of ∼600Myr for the fastest rotators. After this brief episode of large magnetic activity decay, the average chromospheric and coronal emission levels of solar-mass stars decrease steadily converging towards similar values (R'HK~=10–5 and LX~=1027erg/s) by the age of the Sun. Conclusion. The study suggests that solar mass stars in open clusters with ages between ∼30 and ∼600Myr exhibit bimodal distributions of their R'HK chromospheric activity indices and coronal X-ray to bolometric luminosity ratios that can be traced back to their rotation evolution. This conclusion is consistent with available measurements of activity indices from Sun-like stars in nearby open clusters.

Abstract Copyright: © ESO 2018

Journal keyword(s): open clusters and associations: general - stars: activity - stars: chromospheres - stars: coronae - stars: solar-type - Sun: evolution

Simbad objects: 13

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Number of rows : 13

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NGC 869 OpC 02 19 00 +57 07.7           ~ 426 0
2 Cl Melotte 20 OpC 03 26 42 +48 48.0           ~ 750 0
3 Cl Melotte 22 OpC 03 47 00 +24 07.0           ~ 2979 0
4 Cl Melotte 25 OpC 04 26 54.00 +15 52 00.0           ~ 2654 0
5 M 37 OpC 05 52 18 +32 33.2   6.19 5.6     ~ 332 2
6 NGC 2168 OpC 06 08 54 +24 20.0           ~ 457 0
7 NGC 2323 OpC 07 02 47.5 -08 20 16           ~ 154 0
8 NGC 2362 OpC 07 18 41 -24 57.3     4.1     ~ 361 0
9 NGC 2547 OpC 08 09 52.360 -49 10 35.01           ~ 310 0
10 NGC 2632 OpC 08 40 24 +19 40.0           ~ 1224 0
11 NGC 2682 OpC 08 51 18 +11 48.0           ~ 2032 0
12 NGC 6811 OpC 19 37 17 +46 23.3   7.47 6.8     ~ 250 0
13 NGC 6819 OpC 19 41 18 +40 11.2   8.21 7.3     ~ 465 0

    Equat.    Gal    SGal    Ecl

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2020.07.10-03:13:35

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