2009A&A...505..299S


Query : 2009A&A...505..299S

2009A&A...505..299S - Astronomy and Astrophysics, volume 505, 299-306 (2009/10-1)

No first ionization potential fractionation in the active stars AR Piscium and AY Ceti.

SANZ-FORCADA J., AFFER L. and MICELA G.

Abstract (from CDS):

The comparison of coronal and photospheric abundances in cool stars is an essential question to resolve. In the Sun an enhancement of the elements with low first ionization potential (FIP) is observed in the corona with respect to the photosphere. Stars with high levels of activity seem to show a depletion of elements with low FIP when compared to solar standard values; however, the few cases of active stars in which photospheric values are available for comparison lead to confusing results, and an enlargement of the sample is mandatory for solving this longstanding problem. We calculate in this paper the photospheric and coronal abundances of two well known active binary systems, AR Psc and AY Cet, to get further insight into the complications of coronal abundances. Coronal abundances of 9 elements were calculated by means of the reconstruction of a detailed emission measure distribution, using a line-based method that considers the lines from different elements separately. Photospheric abundances of 8 elements were calculated using high-resolution optical spectra of the stars. The results once again show a lack of any FIP-related effect in the coronal abundances of the stars. The presence of metal abundance depletion (MAD) or inverse FIP effects in some stars could stem from a mistaken comparison to solar photospheric values or from a deficient calculation of photospheric abundances in fast-rotating stars. The lack of FIP fractionation seems to confirm that Alfven waves combined with pondermotive forces are dominant in the corona of active stars.

Abstract Copyright:

Journal keyword(s): stars: coronae - stars: abundances - stars: individual: AR Psc - X-rays: stars - line: identification - stars: individual: AY Cet

Simbad objects: 17

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Number of rows : 17
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 * 39 Cet RS* 01 16 36.2879453688 -02 30 01.328624496   6.310 5.428     G6III:eFe-2 257 0
2 HD 8357 XB* 01 22 56.7568636416 +07 25 09.332224320 8.530 8.160   6.8   G5 172 0
3 * eps Eri BY* 03 32 55.8444911587 -09 27 29.739493865 5.19 4.61 3.73 3.00 2.54 K2V 1947 1
4 V* YY Men Ro* 04 58 17.9369735112 -75 16 37.987856868   9.11 8.05     K1IIIp 125 0
5 * alf Aur SB* 05 16 41.35871 +45 59 52.7693 1.33 0.88 0.08 -0.52 -0.96 G3III: 1181 0
6 V* AB Dor TT* 05 28 44.8712165880 -65 26 55.199147208 8.259 7.856 6.999 6.496 5.993 K0V 1028 0
7 * alf CMi SB* 07 39 18.11950 +05 13 29.9552 0.82 0.79 0.37 -0.05 -0.28 F5IV-V+DQZ 1869 0
8 * ksi UMa B SB* 11 18 10.8360115405 +31 31 44.821690914   5.41 4.77 4.4   G2V 338 1
9 V* V851 Cen RS* 13 44 00.9212469648 -61 21 59.173175844   8.74 7.798   6.638 K0III 86 0
10 V* EK Dra BY* 14 39 00.2104038120 +64 17 29.979649860   8.243 7.604     G5VFe-0.7CH-1(k) 449 0
11 * alf Cen ** 14 39 36.50 -60 50 02.3   0.4 -0.1     G2V+K1V 956 0
12 * sig CrB RS* 16 14 40.85557 +33 51 30.9497           F6V+G0V 495 0
13 * 36 Oph ** 17 15 20.9839376 -26 36 10.157115           K2V+K1V 137 0
14 * 70 Oph ** 18 05 27.28518 +02 30 00.3558 5.40 4.89 4.03 3.38 2.92 K0-V 652 0
15 V* AR Lac RS* 22 08 40.8182089680 +45 44 32.107863120 7.09 6.83 6.11     K0IVe+G5IV 727 0
16 * lam And RS* 23 37 33.8427800830 +46 27 29.344721109 5.54 4.84 3.82 3.04 2.47 G8IVk 672 0
17 HD 224085 RS* 23 55 04.0520383542 +28 38 01.245426862 8.88 8.20   6.9   K2+IVeFe-1 732 0

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