2001A&A...370..157S


C.D.S. - SIMBAD4 rel 1.7 - 2020.08.09CEST06:47:58

2001A&A...370..157S - Astronomy and Astrophysics, volume 370, 157-169 (2001/4-4)

ROSAT all-sky survey of W Ursae Majoris stars and the problem of supersaturation.

STEPIEN K., SCHMITT J.H.M.M. and VOGES W.

Abstract (from CDS):

From ROSAT all-sky survey (RASS) data we obtained X-ray fluxes for 57 W UMa type contact systems. In our sample we detected three stars which are the shortest period main sequence binaries ever found as X-ray sources. For stars with (B-V)0<0.6 the normalized X-ray flux decreases with a decreasing color index but for (B-V)0>0.6 a plateau is reached, similar to the saturation level observed for single, rapidly rotating stars. The X-ray flux of W UMa stars is about 4-5 times weaker than that of the fastest rotating single stars. Because early type, low activity variables have longer periods, an apparent period-activity relation is seen among our stars, while cool stars with (B-V)0>0.6 and rotation periods between 0.23 and 0.45 days do not show any such relation. The lower X-ray emission of the single, ultra fast rotators (UFRs) and W UMa stars is interpreted as the result of a decreased coronal filling factor. The physical mechanisms responsible for the decreased surface coverage differs for UFRs and W UMa systems. For UFRs we propose strong polar updrafts within a convection zone, driven by nonuniform heating from below. The updrafts should be accompanied by large scale poleward flows near the bottom of the convective layer and equatorward flows in the surface layers. The flows drag dynamo generated fields toward the poles and create a field-free equatorial region with a width depending on the stellar rotation rate. For W UMa stars we propose that a large scale horizontal flow embracing both stars will prevent the magnetic field from producing long-lived structures filled with hot X-ray emitting plasma. The decreased activity of the fastest rotating UFRs increases the angular momentum loss time scale of stars in a supersaturated state. Thus the existence of a period cutoff and a limiting mass of W UMa stars can be naturally explained.

Abstract Copyright:

Journal keyword(s): stars: activity - (stars:) binaries: eclipsing - stars: coronae - stars: late type - stars: rotation - X-rays: stars

CDS comments: Several 1RXS J... do not exist in the RASS catalogue. Some are replaced by existing 1RXS, the others are renamed RX J...

Simbad objects: 122

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Number of rows : 122

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 V* AQ Tuc EB* 00 17 21.5138001102 -71 54 56.848760060   10.44 10.12     F3/5(+A) 57 0
2 V* CN And WU* 00 20 30.5420869255 +40 13 33.803422638   10.24 9.706     F5V 111 0
3 V* BH Cas EB* 00 21 21.3765858027 +59 09 05.413691241   13.26 12.77     K4V 44 0
4 V* V523 Cas EB* 00 40 06.2678868929 +50 14 15.516158313       10.405   K4V 150 0
5 V* CW Cas EB* 00 45 52.7049598333 +63 05 08.453600159   12.10 11.31     G8V 93 0
6 V* ER Cep EB* 00 50 27.6926266264 +85 15 08.487204979 17.145 16.635 15.809 15.175 14.804 ~ 56 0
7 V* AD Phe WU* 01 16 38.0705633402 -39 42 31.333170513   11.06 10.47     ~ 33 0
8 V* AQ Psc WU* 01 21 03.5556896246 +07 36 21.618400049   9.20 8.69   8.053 F8 52 0
9 V* AE Phe WU* 01 32 32.9321973079 -49 31 41.290852285   8.75 8.15     G4V 113 0
10 V* GW Cep EB* 01 45 58.6221078692 +80 04 55.325040324   11.72 11.21     G3 60 0
11 V* TW Cet EB* 01 48 54.1434549440 -20 53 34.595492634   11.25 10.61   9.787 G5+G8 84 0
12 V* VY Cet EB* 01 49 33.6922704694 -19 37 29.252171890   12.09 11.48 11.006   ~ 28 0
13 NGC 752 OpC 01 57 41 +37 47.1           ~ 538 0
14 V* QX And EB* 01 57 57.7817802186 +37 48 22.450045733   11.91 11.43 11.23   F5 91 0
15 V* SS Ari EB* 02 04 18.4070835062 +24 00 02.292158581   11.00 10.15     G0 103 0
16 V* UX Eri EB* 03 09 52.7437514915 -06 53 33.510267719   11.61 10.97     F9V 79 0
17 V* V524 Per BY* 03 18 58.6912098352 +48 50 42.354407877     13.609     K5 15 0
18 Cl Melotte 20 OpC 03 26 42 +48 48.0           ~ 752 0
19 V* GK Per No* 03 31 12.0096626899 +43 54 15.467450081   10.2 14.0     K1IV 866 0
20 Cl Melotte 22 OpC 03 47 00 +24 07.0           ~ 2990 0
21 V* BV Eri EB* 03 51 53.3423789055 -10 31 49.466329635   8.69       F2V 46 0
22 V* RU Eri bL* 03 54 43.7742877243 -14 56 06.649923251   9.86 9.39     F3V 41 0
23 V* YY Eri WU* 04 12 08.8494411846 -10 28 09.993813939   9.08 8.41   7.673 G3/K0+(F/G) 204 0
24 V* SY Hor WU* 04 14 18.3595269051 -46 26 57.110128490   11.96 11.36 11.114 10.251 ~ 18 0
25 V* AO Cam EB* 04 28 13.6470237835 +53 02 44.465212969   11.23 10.51     G0V 87 0
26 V* RZ Tau EB* 04 36 37.6612742555 +18 45 17.794204502   10.79 10.19     F5 132 0
27 V* UZ Oct WU* 04 43 35.9619560492 -84 48 39.925541263   9.72 9.21     ~ 29 0
28 V* AP Dor WU* 05 06 45.0919973349 -59 03 03.455782184   9.76 9.37     F5V 27 0
29 V* ER Ori EB* 05 11 14.5046439527 -08 33 24.601331471   10.02 9.46     G1V: 169 0
30 V* RS Col Ce* 05 15 31.2444185062 -28 45 02.127028814   10.27 9.67     G0V 38 0
31 V* RW Dor WU* 05 18 32.5454675242 -68 13 32.777407023   11.85 11.16 8.66 10.111 G4/5V 72 0
32 V* TY Men RR* 05 26 49.7267905252 -81 35 07.207190402   8.51 8.26   7.913 A3/4V 58 0
33 V* V781 Tau WU* 05 50 13.1257943382 +26 57 43.362139205   9.28 8.67   7.976 G0 93 0
34 V* TY Pup WU* 07 32 46.2312584822 -20 47 31.076324950   8.99 8.60     F3V 73 0
35 V* HI Pup WU* 07 33 38.2099558859 -50 07 25.042300452   11.09 10.54     ~ 25 0
36 V* FG Hya WU* 08 27 03.9413981176 +03 30 52.329514882   10.62 10.04   9.401 G0 171 0
37 V* TX Cnc EB* 08 40 01.7039481625 +18 59 59.422657649   10.71 9.97 9.88   G0-G1V 203 0
38 V* BU Vel EB* 08 40 06.2923988882 -42 49 43.378848085   11.08 10.78     F0 30 0
39 NGC 2632 OpC 08 40 24 +19 40.0           ~ 1232 0
40 IC 2391 OpC 08 40 32 -53 02.0           ~ 717 0
41 V* AD Cnc EB* 08 46 20.1002033642 +10 20 07.363744039   13.80 13.06     K0V 81 0
42 NGC 2682 OpC 08 51 18 +11 48.0           ~ 2037 0
43 Cl* NGC 2682 SAND 1036 EB* 08 51 28.1469824237 +11 49 27.498107329 13.262 13.27 12.809   12.184 F3 65 0
44 Cl* NGC 2682 SAND 1282 EB* 08 51 37.8473687335 +11 50 57.092630015 13.964 13.89 13.333   12.634 F7V 141 0
45 V* DF Hya EB* 08 55 02.2431734260 +06 05 37.587085714   11.45 10.80     G0 60 0
46 V* UV Lyn EB* 09 03 24.1260387911 +38 05 54.597326087   10.23 9.56     G0 90 0
47 V* S Ant EB* 09 32 18.3865325173 -28 37 39.967890838   6.77 6.45     F3V 128 0
48 V* W UMa WU* 09 43 45.4704899627 +55 57 09.066718574   8.54 7.75     G2Vn 632 1
49 V* AA UMa EB* 09 46 59.2851785172 +45 45 56.389509471   11.48 11.71     G0 72 0
50 V* RT LMi EB* 09 49 48.3190737270 +34 27 15.425664421   12.11 11.35 10.99   F7V 63 0
51 V* XY Leo WU* 10 01 40.4149118298 +17 24 32.578710513   10.66 9.68   8.474 K0V 259 0
52 V* XZ Leo WU* 10 02 34.1961100316 +17 02 47.142539645   10.79 10.37     A5 91 0
53 V* Y Sex WU* 10 02 47.9689716565 +01 05 40.183887562   10.38 9.95 9.875   F3/5V 98 0
54 V* UZ Leo WU* 10 40 33.1851453182 +13 34 00.856206822   10.13 9.75     F2 125 0
55 IC 2602 OpC 10 42 58 -64 24.0           ~ 551 0
56 V* AM Leo WU* 11 02 10.8845725849 +09 53 42.658542812   9.86 9.33   8.417 F8Vn 177 0
57 V* AP Leo WU* 11 05 05.0210506008 +05 09 06.407478312   10.07 9.57   8.849 F8V 110 0
58 V* AW UMa WU* 11 30 04.3159101276 +29 57 52.677255375   7.27   6.7   F0 265 1
59 V* TV Mus WU* 11 39 57.7650431238 -64 48 59.218089690   11.48 10.75   9.712 F2 63 0
60 V* V752 Cen EB* 11 42 48.0813388953 -35 48 57.503249188   9.88 9.30 9.697   F7/G0(V) 71 0
61 V* CE Leo EB* 11 44 24.2553681651 +23 21 22.850397594     12.39     K 82 0
62 V* AG Vir WU* 12 01 03.5038236924 +13 00 30.018273805   8.78 8.52     A7V 151 0
63 V* EH Hya WU* 12 04 50.9662614249 -33 09 22.466907843     14.33     ~ 17 0
64 V* W Crv EB* 12 07 34.3572506786 -13 08 59.016512619   11.95 11.28     ~ 71 0
65 V* TY UMa EB* 12 09 02.4999496149 +56 01 53.953473867   12.42 11.59     F8+F0 75 0
66 V* CC Com WU* 12 12 06.0377635998 +22 31 58.684494436   13.09 11.42   10.085 K4/5V 195 0
67 HD 106400 WU* 12 14 20.99618 +11 49 09.3870   9.94 9.22 9.37 8.390 G8V 216 0
68 V* RW Com EB* 12 33 00.2841958714 +26 42 58.362399221   12.33 11.682 10.929   G8e 143 0
69 V* RZ Com EB* 12 35 05.0595716847 +23 20 14.030368274   11.09 10.57     G0Vn 177 0
70 V* RV Crv bL* 12 37 40.7106798062 -19 34 40.034437690   9.13 8.76     F0V 59 0
71 V* SX Crv WU* 12 40 15.0428795155 -18 48 00.939139142   9.56 9.108   8.412 F7V 74 0
72 V* BI CVn EB* 13 03 16.4093211549 +36 37 00.645296050   10.99 10.31     F9V 78 0
73 V* XY Boo EB* 13 49 11.5668982802 +20 11 24.591106089   10.71 10.54     F5V 136 0
74 HD 120734 EB* 13 51 55.7389560858 -36 37 24.833755638   9.13 8.54   7.771 G0V+G0V 63 0
75 V* TU Boo EB* 14 04 58.0475314650 +30 00 01.588837705   12.22 11.61 12.09   G3 68 0
76 V* V759 Cen EB* 14 10 41.2606316489 -47 46 08.388230489   8.11 7.54     G0V 51 0
77 V* RR Cen EB* 14 16 57.2205732062 -57 51 15.655885175 7.70 7.65 7.29     A9/F0V 133 0
78 V* VW Boo EB* 14 17 26.0324383137 +12 34 03.449790911   11.33 10.55   9.777 G5 98 0
79 V* CK Boo EB* 14 35 03.7594697546 +09 06 49.375637476   9.61 9.029   8.414 F7/8V 119 0
80 V* V677 Cen EB* 14 42 34.6428635653 -40 27 16.018950525   11.47 10.85   10.00 ~ 25 0
81 V* GR Vir WU* 14 45 20.2633088053 -06 44 04.130465519   8.54 8.00   7.34 G2/3V 121 0
82 V* AC Boo EB* 14 56 28.3365272776 +46 21 44.072652819   10.74 10.23     F8Vn 118 0
83 V* TY Boo EB* 15 00 46.9394774048 +35 07 54.743547575   12.03 11.39 11.38   G3+G7 121 0
84 * i Boo EB* 15 03 47.29565 +47 39 14.6228   5.41 4.76     G0Vn 523 0
85 * i Boo B SB* 15 03 47.5145615709 +47 39 16.128926807   6.82 6.004     G9: 53 1
86 V* TZ Boo EB* 15 08 09.1344964536 +39 58 12.864002715   10.60       G2Vn 189 0
87 V* BW Dra WU* 15 11 50.0992475613 +61 51 41.230539303   9.39   8.3   B0 117 2
88 V* BV Dra WU* 15 11 50.3595172449 +61 51 25.282913496   8.54   7.7   F9V+F8V 143 2
89 V* AU Ser WU* 15 56 49.4688123911 +22 16 01.590194012   11.76 11.04 10.93   G4V 93 0
90 V* CM Dra BY* 16 34 20.3299130309 +57 09 44.365524588   14.50 12.87 10.85 9.26 M4.5V 404 0
91 V* V502 Oph WU* 16 41 20.8609964438 +00 30 27.383882425   9.15 8.50   7.865 G2V+F9V 173 0
92 V* AK Her WU* 17 13 57.8235712254 +16 21 00.617382214   9.04 8.51   7.874 F8Vv 246 0
93 V* V535 Ara EB* 17 38 05.5503137405 -56 49 17.291674231   7.69 7.36     A8V 85 0
94 V* V566 Oph WU* 17 56 52.4104254187 +04 59 15.324800914   8.03 7.58     F5V 237 0
95 V* V508 Oph WU* 17 58 48.6178959241 +13 29 46.282169772   11.25 10.65     G5 98 0
96 OGLE BW3 V38 EB* 18 04 44.2034110073 -30 09 05.505472642     18.300   16.3335 ~ 39 0
97 V* FS CrA WU* 18 06 12.1976739073 -37 31 29.638446615           ~ 16 0
98 V* V839 Oph EB* 18 09 21.2653297696 +09 09 03.605427060   9.62 9.03   8.286 F8V 129 0
99 V* FG Sct WU* 18 45 03.6522533220 -06 06 15.514973295           ~ 23 0
100 * eps CrA EB* 18 58 43.3840785329 -37 06 26.377252402   5.19 4.83     F4VFe-0.8+ 190 0
101 V* V803 Aql EB* 19 00 44.1854268626 -07 28 53.972949617           ~ 33 0
102 V* OO Aql EB* 19 48 12.6527583988 +09 18 32.374120037   10.26 9.49   8.762 G5V 215 1
103 V* CV Cyg WU* 19 54 20.9059486857 +38 02 49.972219764       10.60 10.320 F8III 56 0
104 V* V700 Cyg EB* 20 31 05.2475490142 +38 47 00.458769161   12.36 11.14     G2V 60 0
105 V* ST Ind WU* 20 35 23.8073509083 -48 19 19.783723134   11.83 11.12     ~ 17 0
106 V* VW Cep EB* 20 37 21.6248469581 +75 36 01.889162699   8.13   7.0   G8V+K0V 523 0
107 V* MW Pav EB* 20 46 27.7482468407 -71 56 58.465629949   9.15 8.79     F3IV/V 60 0
108 V* LS Del WU* 20 57 10.2862992640 +19 38 59.243423876   9.178 8.722 8.3 8.054 G5 63 0
109 V* BI Vul WU* 21 22 48.0350460134 +27 01 39.845571725           ~ 44 0
110 V* V1073 Cyg WU* 21 25 00.3572317438 +33 41 14.937113872   8.78 8.38     A1VpSi: 127 0
111 V* DK Cyg EB* 21 35 02.6694770300 +34 35 45.398785963   10.98 10.56     A6V 128 0
112 V* BX Peg EB* 21 38 49.3905754055 +26 41 34.205957391     10.890     G4.5 126 0
113 V* RW PsA WU* 22 09 46.9306309253 -27 04 01.518519563   11.93 11.16     ~ 33 0
114 V* BB Peg EB* 22 22 56.8918060653 +16 19 27.858385096   11.69 11.17     F8V 105 0
115 V* EM Lac WU* 22 23 54.7819593951 +54 01 09.270291922   12.20       ~ 39 0
116 V* SW Lac WU* 22 53 41.6541327083 +37 56 18.604271966   9.65 8.51     K0Vv 349 0
117 V* AB And EB* 23 11 32.0860884375 +36 53 35.107206154   10.62 9.50     G5+G5V 251 0
118 V* WZ Cep EB* 23 22 24.1932513922 +72 54 56.832888411   11.97 11.48     F5 64 0
119 V* VZ Psc WU* 23 27 48.3882787476 +04 51 23.935673863   11.39 10.274 10.090 8.926 K4/5V 97 0
120 V* BK And RR* 23 35 06.0326911269 +41 06 10.470713506   12.20 12.88     ~ 31 0
121 V* EL Aqr EB* 23 47 18.3455361182 -08 05 12.097350816   10.91 10.41     F 34 0
122 V* U Peg WU* 23 57 58.4767547238 +15 57 10.083936262   10.26 9.63   8.970 G2V 235 0

    Equat.    Gal    SGal    Ecl

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2020.08.09-06:47:58

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