2003ApJ...585..993R


Query : 2003ApJ...585..993R

2003ApJ...585..993R - Astrophys. J., 585, 993-1006 (2003/March-2)

A Far Ultraviolet Spectroscopic Explorer survey of coronal forbidden lines in late-type stars.

REDFIELD S., AYRES T.R., LINSKY J.L., AKE T.B., DUPREE A.K., ROBINSON R.D. and YOUNG P.R.

Abstract (from CDS):

We present a survey of coronal forbidden lines detected in Far Ultraviolet Spectroscopic Explorer (FUSE) spectra of nearby stars. Two strong coronal features, Fe XVIII λ974 and Fe XIX λ1118, are observed in 10 of the 26 stars in our sample. Various other coronal forbidden lines, observed in solar flares, also were sought but not detected. The Fe XVIII feature, formed at logT=6.8 K, appears to be free of blends, whereas the Fe XIX line can be corrupted by a C I multiplet. FUSE observations of these forbidden iron lines at spectral resolution λ/Δλ∼15,000 provides the opportunity to study dynamics of hot coronal plasmas. We find that the velocity centroid of the Fe XVIII feature deviates little from the stellar rest frame, confirming that the hot coronal plasma is confined. The observed line widths generally are consistent with thermal broadening at the high temperatures of formation and show little indication of additional turbulent broadening. The fastest rotating stars, 31 Com, α Aur Ab, and AB Dor, show evidence for excess broadening beyond the thermal component and the photospheric vsini. The anomalously large widths in these fast-rotating targets may be evidence for enhanced rotational broadening, consistent with emission from coronal regions extending an additional ΔR∼0.4-1.3R*above the stellar photosphere, or represent the turbulent broadening caused by flows along magnetic loop structures. For the stars in which Fe XVIII is detected, there is an excellent correlation between the observed Röntgensatellit (ROSAT) 0.2-2.0 keV soft X-ray flux and the coronal forbidden line flux. As a result, Fe XVIII is a powerful new diagnostic of coronal thermal conditions and dynamics that can be utilized to study high-temperature plasma processes in late-type stars. In particular, FUSE provides the opportunity to obtain observations of important transition region lines in the far-UV, as well as simultaneous measurements of soft X-ray coronal emission, using the Fe XVIII coronal forbidden line.

Abstract Copyright:

Journal keyword(s): Line: Profiles - Stars: Coronae - Stars: Late-Type - Ultraviolet: Stars - X-Rays: Stars

Simbad objects: 28

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Number of rows : 28
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#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-1 508 0
2 * 47 Cas PM* 02 05 07.4242273 +77 16 52.824198   5.590 5.268     F0V 112 1
3 * eps Eri BY* 03 32 55.8444911587 -09 27 29.739493865 5.19 4.61 3.73 3.00 2.54 K2V 1806 1
4 HD 22468 RS* 03 36 47.2911034958 +00 35 15.938962144 7.09 6.79 5.90 5.4   K2:Vnk 1147 0
5 V* V1228 Tau dS* 03 47 24.0779661960 +24 35 18.510029196   7.89 7.71 7.5 7.45 A4V 87 0
6 * alf Tau LP? 04 35 55.23907 +16 30 33.4885 4.32 2.40 0.86 -0.37 -1.31 K5+III 1216 1
7 * alf Aur SB* 05 16 41.35871 +45 59 52.7693 1.33 0.88 0.08 -0.52 -0.96 G3III: 1159 0
8 V* AB Dor TT* 05 28 44.8712165880 -65 26 55.199147208 8.259 7.856 6.999 6.496 5.993 K0V 976 0
9 * alf Ori s*r 05 55 10.30536 +07 24 25.4304 4.38 2.27 0.42 -1.17 -2.45 M1-M2Ia-Iab 1567 0
10 * alf Car * 06 23 57.10988 -52 41 44.3810 -0.49 -0.59 -0.74 -0.96 -1.13 A9II 436 0
11 * alf CMi SB* 07 39 18.11950 +05 13 29.9552 0.82 0.79 0.37 -0.05 -0.28 F5IV-V+DQZ 1822 0
12 * bet Gem PM* 07 45 18.94987 +28 01 34.3160 3.00 2.14 1.14 0.39 -0.11 K0IIIb 1075 1
13 * d UMa RS* 09 34 28.8594727848 +69 49 49.226541888 5.67 5.34 4.57 3.91 3.50 G5III-IV 286 0
14 * mu. Vel ** 10 46 46.17877 -49 25 12.9244 4.16 3.59 2.69 2.01 1.52 G6III 177 0
15 V* TW Hya TT* 11 01 51.9053285064 -34 42 17.033218380   11.94 10.50 10.626 9.18 K6Ve 1745 1
16 * 31 Com Ro* 12 51 41.9201696640 +27 32 26.565016812 5.81 5.61 4.94 4.39 4.04 G0IIIp 417 1
17 NAME Proxima Centauri Er* 14 29 42.9461331854 -62 40 46.164680672 14.21 12.95 11.13 9.45 7.41 M5.5Ve 1137 0
18 V* EK Dra BY* 14 39 00.2104038120 +64 17 29.979649860   8.243 7.604     G1.5V 410 0
19 * alf Cen B PM* 14 39 35.06311 -60 50 15.0992 2.89 2.21 1.33     K1V 963 1
20 * alf Cen A SB* 14 39 36.49400 -60 50 02.3737 0.96 0.72 0.01     G2V 1206 0
21 V* V856 Sco Ae* 16 08 34.2870044544 -39 06 18.325711332 7.66 7.41 7.05 6.92   A7IIIne_sh 370 0
22 * alf TrA * 16 48 39.89508 -69 01 39.7626   3.33 1.88     K2III_Ba1 234 0
23 * bet Dra * 17 30 25.9616959 +52 18 04.999351 4.43 3.79 2.81 2.12 1.64 G2Ib-IIa 402 0
24 * alf Aql dS* 19 50 46.99855 +08 52 05.9563 1.07 0.98 0.76 0.62 0.49 A7Vn 848 0
25 V* AU Mic LM* 20 45 09.5324974119 -31 20 27.237889841   10.05 8.627 9.078 6.593 M1VeBa1 1006 0
26 * alf Aqr * 22 05 47.0359315 -00 19 11.456766 4.65 3.90 2.94 2.27 1.76 G2Ib 428 0
27 * ups Peg PM* 23 25 22.7828725585 +23 24 14.762916815 5.15 5.01 4.40 3.86 3.54 F8III 247 0
28 V* OU And Ro* 23 49 40.9595121216 +36 25 31.013370732   6.69 5.90     G1IIICaIIem 135 0

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2022.07.06-09:02:10

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