2003ApJS..145..147S


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.15CET00:03:46

2003ApJS..145..147S - Astrophys. J., Suppl. Ser., 145, 147-179 (2003/March-0)

The structure of stellar coronae in active binary systems.

SANZ-FORCADA J., BRICKHOUSE N.S. and DUPREE A.K.

Abstract (from CDS):

A survey of 28 stars (22 active binary systems, plus six single stars or wide binaries for comparison) using extreme ultraviolet spectra has been conducted to establish the structure of stellar coronae in active binary systems from the emission measure distribution (EMD), electron densities, and scale sizes. Observations obtained by the Extreme Ultraviolet Explorer satellite (EUVE) during 9 years of operation are included for the stars in the sample. EUVE data allow a continuous EMD to be constructed in the range logTe(K)∼5.6-7.4, using iron emission lines. These data are complemented with IUE observations to model the lower temperature range [logTe(K)∼4.0-5.6]. Inspection of the EMD shows an outstanding narrow enhancement, or ``bump'' peaking around logTe(K)∼6.9 in 25 of the stars, defining a fundamental coronal structure. The emission measure per unit stellar area decreases with increasing orbital (or photometric) periods of the target stars; stars in binaries generally have more material at coronal temperatures than slowly rotating single stars. High electron densities (Ne≳1012 cm–3) are derived at ∼logTe(K)∼7.0 for some targets, implying small emitting volumes.

The observations suggest the magnetic stellar coronae of these stars are consistent with two basic classes of magnetic loops: solar-like loops with maximum temperature around logTe(K)∼6.3 and lower electron densities (Ne≳109-1010.5 cm–3), and hotter loops peaking around logTe(K)∼6.9 with higher electron densities (Ne≳1012 cm–3). For the most active stars, material exists at much higher temperatures [logTe(K)≥6.9] as well. However, current ab initio stellar loop models cannot reproduce such a configuration. Analysis of the light curves of these systems reveals signatures of rotation of coronal material, as well as apparent seasonal (i.e., year-to-year) changes in the activity levels.

Abstract Copyright:

Journal keyword(s): Stars: Coronae - Stars: Flare - Ultraviolet: Stars - X-Rays: Stars

Simbad objects: 30

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Number of rows : 30

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 * bet Cet PM* 00 43 35.37090 -17 59 11.7827 3.90 3.02 2.01 1.29 0.78 G9.5IIICH-1 495 0
2 * 39 Cet RS* 01 16 36.2882494986 -02 30 01.329588503   6.310 5.428     G6III:eFe-2 242 0
3 HD 8357 XB* 01 22 56.7569725665 +07 25 09.324761789 8.530 8.160   6.8   G5 155 0
4 V* CC Eri BY* 02 34 22.5662436236 -43 47 46.871752741 11.305 10.201 8.865 7.926 6.992 K7V 247 0
5 V* VY Ari RS* 02 48 43.7283572894 +31 06 54.592580835   7.72   6.4   G9 205 0
6 V* UX Ari RS* 03 26 35.3764089427 +28 42 54.211100955 7.76 7.28 6.37     K0IV 658 0
7 * eps Eri BY* 03 32 55.8449634 -09 27 29.731165 5.19 4.61 3.73 3.00 2.54 K2V 1659 1
8 HD 22468 RS* 03 36 47.2911034958 +00 35 15.938962144 7.09 6.63   5.4   K2:Vnk 1117 0
9 * alf Aur SB* 05 16 41.35871 +45 59 52.7693 1.33 0.88 0.08 -0.52 -0.96 G3III: 1133 0
10 HD 36705 TT* 05 28 44.8916324761 -65 26 55.289846904 8.259 7.856 6.999 6.496 5.993 K0V 910 0
11 * alf Gem A SB* 07 34 35.863 +31 53 17.79     1.9     A1.5IV+ 379 0
12 * alf CMi SB* 07 39 18.11950 +05 13 29.9552 0.82 0.79 0.37 -0.05 -0.28 F5IV-V+DQZ 1742 0
13 V* BF Lyn BY* 09 22 25.9436108516 +40 12 03.806653234   8.62   7.1   K2.5Vke 115 0
14 V* LQ Hya BY* 09 32 25.5684079124 -11 11 04.687410738 9.316 8.761 7.891 7.288 6.815 K1Vp 394 0
15 V* DH Leo RS* 10 00 01.7102607868 +24 33 10.098116028   9.47 7.982 7.3 6.898 K0Vk 152 0
16 * ksi UMa B SB* 11 18 10.8360115405 +31 31 44.821690914   5.38 4.729 4.4   G2V 326 2
17 V* BH CVn RS* 13 34 47.8087874928 +37 10 56.694070527 5.43 5.38 4.98 4.57 4.27 A6m 316 0
18 * alf Cen ** 14 39 29.71993 -60 49 55.9990   0.4 -0.1     G2V+K1V 792 0
19 * alf Cen B PM* 14 39 35.06311 -60 50 15.0992 2.89 2.21 1.33     K1V 865 1
20 * alf Cen A SB* 14 39 36.49400 -60 50 02.3737 0.96 0.72 0.01     G2V 1110 0
21 * sig CrB RS* 16 14 40.85557 +33 51 30.9497           F6V+G0V 473 0
22 HD 155555 RS* 17 17 25.5047544575 -66 57 03.732827572 7.795 7.499 6.723   6.39 K1Vp 247 2
23 V* BY Dra BY* 18 33 55.7719224141 +51 43 08.903033617 10.22 9.23   8.733   K4Ve+K7.5Ve 592 0
24 V* V478 Lyr RS* 19 07 32.3867188674 +30 15 16.176365783   8.54   7.3   G6V 114 0
25 HD 200391 Ae* 21 02 25.9068825509 +27 48 26.439773330   7.93 7.374   6.624 G0V+G5V 334 0
26 V* AR Lac RS* 22 08 40.8180372773 +45 44 32.104045703 7.09 6.83 6.11     K0IVe+G5IV 693 0
27 V* FK Aqr BY* 22 38 45.5745793091 -20 37 16.086999376 11.714 10.595 9.083 8.073 6.876 M0Vep 250 0
28 * sig Peg PM* 22 52 24.0744875405 +09 50 08.386917893   5.64   4.9   F6V 250 0
29 * lam And RS* 23 37 33.8426114 +46 27 29.337984 5.54 4.84 3.82 3.04 2.47 G8IVk 638 0
30 HD 224085 RS* 23 55 04.0516465022 +28 38 01.248194500 8.88 8.20   6.9   K2+IVeFe-1 675 0

    Equat.    Gal    SGal    Ecl

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2019.11.15-00:03:46

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