1998ApJ...506..347B

Query : 1998ApJ...506..347B

1998ApJ...506..347B - Astrophys. J., 506, 347-359 (1998/October-2)

Stellar activity in coeval open clusters: Praesepe and the Hyades.

BARRADO Y NAVASCUES D., STAUFFER J.R. and RANDICH S.

Abstract (from CDS):

Randich & Schmitt found that the coronal activity of solar-type and low-mass stars in Praesepe is significantly lower than that of stars in the Hyades cluster. This result is quite surprising, since the Hyades and Praesepe have approximately the same age and metallicity and are often thought to have originated in the same giant molecular cloud complex. We have carried out several tests in order to find a possible explanation for this result. We have measured radial velocities of two groups of Praesepe stars (a dF-dK sample and a dM sample) and have measured Hα as a chromospheric activity index for the dM sample. Based on analyses of these data, we conclude that the Praesepe catalog used in the X-ray analysis does not contain a significant number of nonmembers and, thus, that membership problems do not seem to be the cause of the Randich & Schmitt result. The comparison of the Hα equivalent widths for the M dwarfs in Praesepe with those in the Hyades indicates that, at least for stars in this mass range, the Praesepe stars are as active or more active than their Hyades counterparts. The similarity of chromospheric emission allows us to reject differences in the rotational velocity distribution as the origin of the dissimilar Lx luminosity functions. We have also analyzed a few ROSAT PSPC pointings of Praesepe in order to obtain a new and independent estimate of the X-ray luminosities and upper limits for a small sample of Praesepe members. This analysis suggests that the previous ROSAT PSPC analysis produced slightly optimistic X-ray upper limits; however, the differences between the old and new upper limits are not large enough to explain the dichotomy in the X-ray properties of Praesepe and the Hyades. Therefore, our examination of the available data does not provide a clear reason to explain why the X-ray luminosity functions of the two clusters are different. Part of the explanation could be found in the binaries. Speculatively, these clusters could have different orbital period distributions, with more short-period binaries among the Hyades, which would show larger coronal activity.

Abstract Copyright: ∼

Journal keyword(s): Galaxy: Open Clusters and Associations: Individual: Name: Hyades - Galaxy: Open Clusters and Associations: Individual: Name: Praesepe - Stars: Activity - Stars: Chromospheres - Stars: Late-Type - X-Rays: Stars

CDS comments: Table 3: stars 'I563' and 'II626' not identified.

Simbad objects: 151

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Number of rows : 151
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 Cl Melotte 25 OpC 04 30 27.4 +16 46 43           ~ 3309 0
2 Cl* NGC 2632 HSHJ 14 ** 08 31 16.926720 +19 21 19.09512           M3V 14 0
3 Cl* NGC 2632 HSHJ 16 LM* 08 31 40.8996554160 +18 29 43.049626116           M2.8 21 0
4 Cl* NGC 2632 HSHJ 23 LM* 08 32 18.8963965128 +19 03 08.663852556           M3.0 21 0
5 Cl* NGC 2632 HSHJ 25 Er* 08 32 46.7952484680 +19 59 51.827581788           M3.4 32 0
6 Cl* NGC 2632 HSHJ 26 Er* 08 32 48.7755617208 +18 40 40.748072340           M3.5 26 0
7 Cl* NGC 2632 JS 669 Er* 08 33 24.6214909104 +19 52 57.803967804   21.25 18.24     M3.7 33 0
8 Cl* NGC 2632 JC 21 Er* 08 33 27.0042754296 +19 20 28.760518464   17.45 15.43     M1.4 21 0
9 Cl* NGC 2632 HSHJ 43 Er* 08 33 33.9434798424 +20 04 25.588493868           M2.3 33 0
10 Cl* NGC 2632 HSHJ 48 * 08 33 45.3 +19 39 16           ~ 2 0
11 Cl* NGC 2632 JC 27 * 08 33 50.7608899584 +19 46 58.622526192   18.01 15.75     M0.5 29 0
12 Cl* NGC 2632 JC 31 * 08 34 02.4574355376 +19 19 21.957590820   19.37 16.17     M2.3 19 0
13 Cl* NGC 2632 HSHJ 60 LM* 08 34 39.6995563128 +19 08 12.808186620           M4V 26 0
14 HIP 42106 Ro* 08 34 59.6263072027 +21 05 49.181111417   11.49 11.01     F8.9 54 0
15 Cl* NGC 2632 JS 83 * 08 35 14.5425406536 +20 47 41.929469232   11.32 10.71     ~ 3 0
16 Cl* NGC 2632 HSHJ 70 * 08 35 14.7710966513 +19 16 31.770423612           M2.9 26 0
17 Cl* NGC 2632 JS 84 * 08 35 16.9517807712 +19 54 53.356691952   19.56 17.03     M1.8 25 0
18 Cl* NGC 2632 JS 87 LM* 08 35 21.6911314848 +18 29 34.189987740   19.24 17.09     M1.8 25 0
19 BD+20 2119 SB* 08 35 28.0464246552 +20 11 46.829643468   10.96 10.48     F8 35 0
20 Cl* NGC 2632 JC 48 * 08 35 33.8700199446 +18 55 47.503258917   16.79 15.04     M0.2 33 0
21 Cl* NGC 2632 JC 49 * 08 35 35.7081065369 +18 59 44.600665676   17.19 15.32     K7.9 26 0
22 Cl* NGC 2632 JS 94 Er* 08 35 39.6720870076 +19 07 36.361719277   19.93 17.28     M3.1 37 0
23 Cl* NGC 2632 JS 95 Er* 08 35 40.1505882528 +18 42 28.352207484   19.95 17.34     M3.3 36 0
24 Cl* NGC 2632 HSHJ 87 LM* 08 35 47.2238439768 +18 08 29.901362748           M5V 30 0
25 Cl* NGC 2632 JS 99 * 08 35 50.8244000088 +18 53 43.613819340   19.93 17.20     ~ 15 0
26 Cl* NGC 2632 JS 103 Ro* 08 35 54.5494164654 +18 08 57.660895075   11.39 10.82     F7.2 40 0
27 Cl* NGC 2632 JS 102 Er* 08 35 56.9481873844 +20 49 34.732649951   12.64 11.85     K0V: 45 0
28 Cl* NGC 2632 HSHJ 94 * 08 35 59.1895094400 +18 18 29.637283500           M1.9 23 0
29 Cl* NGC 2632 JS 105 Er* 08 36 00.4739817912 +17 58 33.396782036   19.19 16.84     M1.9 34 0
30 Cl* NGC 2632 JS 111 Er* 08 36 08.9528233704 +19 09 30.906837000   20.41 17.54     M3.0 36 0
31 Cl* NGC 2632 JC 58 * 08 36 11.4268251007 +19 52 40.284389764   15.57       M0.0 42 0
32 Cl* NGC 2632 JS 124 Er* 08 36 19.0184905023 +18 55 08.541857682   19.46 16.97     M2.3 35 0
33 Cl* NGC 2632 JS 123 LM* 08 36 19.1544915816 +19 53 54.840360840   20.17 17.56     M3.0 38 0
34 Cl* NGC 2632 JS 126 Er* 08 36 21.8140912330 +20 12 19.683948061   19.55 16.98     M1.9 39 0
35 BD+19 2045 SB* 08 36 29.8499465304 +18 57 57.072527496   9.86 9.50     F6V 41 0
36 Cl* NGC 2632 JC 66 * 08 36 33.3841596140 +19 54 54.386181781   18.41 16.27     M1.8 39 0
37 Cl* NGC 2632 JS 146 Ro* 08 36 45.7211129244 +20 07 26.211643713   12.380 11.613     G5.0 55 0
38 Cl* NGC 2632 S 3 * 08 36 46.5740589816 +19 45 44.139618324   12.19 11.39     G 16 0
39 V* CD Cnc Er* 08 36 48.9550658814 +19 18 59.333997747           M1.8 44 0
40 Cl* NGC 2632 JS 158 Er* 08 36 55.9791781056 +19 35 57.002184960   19.55 17.19     M2.2 37 0
41 HD 73081 SB* 08 37 02.0306492832 +19 36 17.217520704   9.649 9.560     F6V 64 0
42 Cl* NGC 2632 JS 163 Er* 08 37 02.6781378782 +19 19 42.473065801   19.37 16.84     M2.1 33 0
43 Cl* NGC 2632 S 12 Ro* 08 37 11.4889240251 +19 48 13.243562709   12.008 11.286     G 75 0
44 Cl* NGC 2632 S 11 SB* 08 37 11.6693226912 +20 17 04.908313392   11.6 11.1     G0V 21 0
45 Cl* NGC 2632 S 13 Ro* 08 37 18.2937089595 +19 41 56.401130140   12.181 11.424     G5V 55 0
46 Cl* NGC 2632 S 14 Ro* 08 37 22.2266341992 +20 10 37.238981570   12.077 11.378     G 65 0
47 K2-95 * 08 37 27.0563032536 +18 58 36.021202824   19.86 17.27     M3V 77 0
48 Cl* NGC 2632 S 16 Ro* 08 37 27.5524241141 +19 37 03.262350678   12.416 11.616     G8V 62 0
49 BD+20 2130 * 08 37 27.9432532416 +19 33 45.180363780   10.35 9.79     F6V 55 0
50 Cl* NGC 2632 HSHJ 165 LM* 08 37 29.4101803056 +18 41 35.532349116           M2.6 18 0
51 Cl* NGC 2632 JC 104 * 08 37 32.2247624497 +18 53 02.334045781   18.22 16.13     M1.4 36 0
52 Cl* NGC 2632 JC 103 Er* 08 37 32.4309788197 +19 31 17.999827310   18.59 16.27     M1.9 38 0
53 Cl* NGC 2632 JC 106 Ro* 08 37 33.0780320188 +18 39 15.605227630   11.249 10.668     G0.0 56 0
54 Cl* NGC 2632 JC 105 Er* 08 37 33.7152424917 +19 18 39.564215974   18.06 16.59     M2.1 34 0
55 Cl* NGC 2632 JS 192 LM* 08 37 34.9719998664 +18 56 07.821273912   19.90 17.52     ~ 11 0
56 BD+19 2052 SB* 08 37 42.3624111120 +19 08 01.578264972   10.29 9.88     F4V 54 0
57 Cl* NGC 2632 JC 112 Ro* 08 37 46.4122408968 +19 35 57.469211340   13.252 12.305     K1V 62 0
58 Cl* NGC 2632 S 25 Ro* 08 37 46.6100294766 +19 26 18.046945074   11.243 10.635     F9V 80 0
59 Cl* NGC 2632 S 27 Er* 08 37 49.9835270928 +19 53 28.876614576   11.65 11.27 11.25   G8V 36 0
60 Cl* NGC 2632 S 29 Ro* 08 37 52.0886192625 +19 59 13.858487594   11.952 11.242     G5V 76 0
61 Cl* NGC 2632 JC 118 Er* 08 37 57.0347637421 +19 14 10.371671238   12.632 11.829     G8V 65 0
62 Cl* NGC 2632 JS 211 Ro* 08 38 07.5810781008 +19 59 16.341099072   12.969 12.061     K1.2 45 0
63 Cl* NGC 2632 JS 212 Ro* 08 38 08.0838379200 +20 26 22.339441163   12.432 11.684     G6.5 58 0
64 Cl* NGC 2632 S 38 Ro* 08 38 14.2659589872 +19 21 55.371324528   11.605 10.897     G5V 40 0
65 Cl* NGC 2632 JS 220 Ro* 08 38 14.9763996707 +20 34 04.157206391   11.89 10.87 11.32   G4.5 54 0
66 K2-100 Ro* 08 38 24.3002838928 +20 06 21.828057218   11.085 10.521     G2 141 0
67 Cl* NGC 2632 S 51 SB* 08 38 50.0070052173 +20 04 03.535888479   11.40 10.80     G0V 63 0
68 BD+20 2140 SB* 08 39 02.8283574888 +19 43 29.007147720   9.781 9.519 9.328   F7V 65 0
69 HD 73429 * 08 39 05.2331969928 +20 07 01.802473932   9.81 9.41     F5V 69 0
70 Cl* NGC 2632 RG 329 * 08 39 10.1433400116 +19 40 42.341782111   9.83 9.41     F4V 55 0
71 NGC 2632 4745 Ro* 08 39 10.9668686184 +18 10 33.558758616   10.86 10.27     F7.5 51 0
72 Cl* NGC 2632 JC 152 Ro* 08 39 12.1725466639 +19 06 56.206134373   11.129 10.568     F9V 79 0
73 Cl* NGC 2632 S 70 Ro* 08 39 14.9923040915 +20 12 38.776945040   11.54 10.86 11.19   G5V 58 0
74 Cl* NGC 2632 ANM 748 * 08 39 16.6434871556 +17 27 46.532319700   11.98 12.11     ~ 32 0
75 BD+19 2061 Ro* 08 39 24.9776363874 +19 27 33.640292958   11.066 10.461     G0V 89 0
76 BD+20 2146 Ro* 08 39 30.4201839168 +20 04 08.581687860   10.892 10.260     F8V 59 0
77 Cl* NGC 2632 S 79 Ro* 08 39 35.5396599646 +18 52 36.750952846   11.282 10.695     G 62 0
78 Cl* NGC 2632 S 83 Ro* 08 39 45.7489350539 +19 22 01.145101156   11.257 10.640     G1V 93 0
79 Cl* NGC 2632 KW 213 Er* 08 39 50.8363831685 +19 33 02.073309982   12.61 11.84     G6.1 51 0
80 Cl* NGC 2632 S 87 Ro* 08 39 52.3360004784 +19 18 45.497218727   10.742 10.217     F7V 81 0
81 HD 73641 * 08 39 58.0671687624 +19 12 05.870783088   9.92 9.54     F3V 93 0
82 NGC 2632 OpC 08 39 58.4 +19 36 33           ~ 1733 0
83 Cl* NGC 2632 KW 236 Ro* 08 39 59.830176 +19 34 00.31224   12.880 11.886 11.649   K 32 0
84 Cl* NGC 2632 JC 177 Ro* 08 39 59.9819394840 +19 34 40.475004204   13.861 12.855     K2.3 56 0
85 Cl* NGC 2632 S 97 Ro* 08 40 00.6247303944 +19 48 23.591711596   10.824 10.271     F6V 70 0
86 V* TX Cnc SB* 08 40 01.7039106928 +18 59 59.421095623   10.71 9.97 9.88 9.339 G0-G1V 254 0
87 Cl* NGC 2632 JC 187 Er* 08 40 05.7148238215 +19 01 30.666359943   13.720 12.706 12.150   K1V 54 0
88 Cl* NGC 2632 S 105 SB* 08 40 06.2752493400 +19 27 14.755630104   10.82 10.25     F6V 29 0
89 Cl* NGC 2632 S 104 Ro* 08 40 06.3564902093 +19 18 26.507970736   11.761 10.980     K4 62 0
90 Cl* NGC 2632 JC 190 Ro* 08 40 09.6806371620 +19 37 17.099047170   12.808 11.973     G9V 74 0
91 K2-102 Ro* 08 40 13.4534275080 +19 46 43.709186244   14.318 13.200     K3V 80 0
92 BD+20 2162 Ro* 08 40 17.623704 +19 47 15.23904   10.551 9.941 9.873   F8V 44 0
93 BD+20 2164 Ro* 08 40 22.3141782973 +20 06 24.323206447   10.42 9.98 9.97   F2III 68 0
94 Cl* NGC 2632 S 118 Ro* 08 40 22.7158598352 +19 27 53.156521224   11.303 10.673     F7.2 74 0
95 Cl* NGC 2632 S 128 Ro* 08 40 27.4367428022 +19 16 40.920833107   11.822 11.148     G3V 74 0
96 Cl* NGC 2632 S 126 Ro* 08 40 28.6411452639 +20 18 44.794197158   12.432 11.604     K 40 0
97 Cl* NGC 2632 S 131 Ro* 08 40 31.6863019661 +19 51 01.012583190   12.402 11.609     G9V 60 0
98 Cl* NGC 2632 S 129 Ro* 08 40 31.8436933055 +20 12 06.018714052   12.201 11.472     G5V 70 0
99 Cl* NGC 2632 JC 215 Ro* 08 40 33.4642580616 +19 38 00.935332332   13.094 12.198     K0.8 66 0
100 Cl* NGC 2632 JC 216 Er* 08 40 33.5986015948 +18 40 28.168343261   12.335 11.596     G5.4 45 0
101 Cl* NGC 2632 S 134 Ro* 08 40 39.9178822906 +19 40 09.192415392   11.580 10.859     G2V 61 0
102 Cl* NGC 2632 S 137 SB* 08 40 41.8979189208 +19 13 25.440770028   11.205 10.567     G0V 44 0
103 Cl* NGC 2632 S 138 Ro* 08 40 42.4813583883 +19 33 57.623817270   12.063 11.331     G4V 84 0
104 BD+19 2074 * 08 40 46.0852462728 +19 18 34.560605340   9.967 9.50     F4V 77 0
105 Cl* NGC 2632 S 145 Er* 08 40 47.6138605389 +18 54 11.925904963   12.159 11.426     G6.8 60 0
106 Cl* NGC 2632 S 143 Ro* 08 40 47.9832672792 +19 39 32.161833069   11.757 10.991     G2V 58 0
107 Cl* NGC 2632 S 144 Ro* 08 40 48.3236450266 +19 55 18.904927804   11.707 11.012     G2V 79 0
108 Cl* NGC 2632 S 148 Ro* 08 40 52.5239203352 +19 28 59.564290896   10.839 10.267     F8V 78 0
109 Cl* NGC 2632 JC 230 Ro* 08 40 56.6914326867 +19 44 05.184258675   13.095 12.198     K0.5 56 0
110 Cl* NGC 2632 JS 404 * 08 41 02.6230647467 +20 27 27.764231749   13.24 12.35     G8.5 49 0
111 BD+19 2076 SB* 08 41 07.363272 +19 04 16.38300     10.161 10.049   F7V 52 0
112 BD+19 2077 SB* 08 41 09.6035844072 +19 51 18.661416948   11.361 10.631     G7.6 60 0
113 BD+20 2176 Ro* 08 41 10.0219180608 +19 30 32.062108356   10.613 10.080     F7V 79 0
114 Cl* NGC 2632 S 155 SB* 08 41 10.3080648125 +19 49 07.006491032   12.268 11.495     G6.6 73 0
115 Cl* NGC 2632 JS 409 * 08 41 11.0531090904 +20 49 57.893568096   12.65 11.92     K0V: 13 0
116 BD+20 2181 Ro* 08 41 25.8429243867 +19 56 36.848107538   11.342 10.687     G0V 91 0
117 Cl* NGC 2632 S 169 Ro* 08 41 28.6832242439 +19 44 48.128029157   11.605 10.933     G1V 55 0
118 Cl* NGC 2632 KW 401 Er* 08 41 30.7065278468 +18 52 18.719809334   13.649 12.727     K3.1 49 0
119 Cl* NGC 2632 JC 258 Ro* 08 41 31.5377420083 +18 30 02.228589704   10.89 10.13     F5 51 0
120 Cl* NGC 2632 S 171 Ro* 08 41 33.8314096798 +19 58 08.719710567   12.503 11.678     G6.7 55 0
121 BD+20 2183 SB* 08 41 42.2956918488 +19 39 37.959407460   10.02 9.60     F6V 63 0
122 Cl* NGC 2632 JC 263 Er* 08 41 43.6896963643 +19 57 43.687711161   13.264 12.333     K1V 49 0
123 BD+20 2184 Ro* 08 41 43.8160475073 +20 13 36.752729096   10.988 10.431     G2 109 1
124 BD+19 2081 * 08 41 45.4929009104 +19 16 02.241278408   10.62 10.16     F7V 73 0
125 Cl* NGC 2632 JS 461 * 08 41 51.9884907672 +20 10 01.150897548   12.89 12.04     K0.0 49 0
126 Cl* NGC 2632 S 184 SB* 08 41 54.3796091961 +19 15 26.592416734   12.104 11.354 11.053   G8V 63 0
127 Cl* NGC 2632 S 186 Pu* 08 41 55.8711349195 +19 41 22.847148847   11.718 11.006 10.796   G2V 65 0
128 Cl* NGC 2632 JS 465 Ro* 08 41 59.2433467618 +20 55 07.164217236   11.83 11.43     G5V: 44 0
129 BD+20 2189 ** 08 42 20.1266735352 +20 02 11.677833168   10.26 9.77     F6V 44 0
130 Cl* NGC 2632 JS 737 Er* 08 42 22.6872746976 +20 07 06.325708296   12.99 12.10     ~ 19 0
131 BD+18 2020 * 08 42 36.8047549608 +18 23 19.832312040   10.536 10.079     G0V: 31 0
132 Cl* NGC 2632 JS 496 Ro* 08 42 40.2090814368 +19 07 59.111896584   12.976 12.111     K0.1 46 0
133 BD+20 2192 * 08 42 40.7205726329 +19 32 35.455346147   10.24 9.87     F2III 59 0
134 Cl* NGC 2632 S 199 Ro* 08 42 42.4975530214 +19 05 58.950946922   12.359 11.596     G5.8 61 0
135 BD+20 2193 * 08 42 44.4151509864 +19 34 47.877586608   10.13 9.73     F6V 52 0
136 Cl* NGC 2632 S 203 Ro* 08 43 00.5482617645 +20 20 16.103893959   12.147 11.384     G5V 59 0
137 BD+19 2087 SB* 08 43 05.9392105920 +19 26 15.288202896   10.52 9.93     F8V 54 0
138 HD 74186 SB* 08 43 07.0511295816 +19 04 06.083872140   10.09 9.56     F8V 59 0
139 Cl* NGC 2632 S 209 Ro* 08 43 10.7666575438 +19 31 34.634872830   12.583 11.769     G6.8 62 0
140 Cl* NGC 2632 S 213 Ro* 08 43 20.1954899736 +19 46 08.530884588   11.415 10.756     G0V 54 0
141 BD+22 1980 SB* 08 43 22.5712415206 +21 40 18.098313041   11.24 10.52     G3.7 53 0
142 BD+20 2196 SB* 08 43 35.5343894337 +20 11 22.517073545   10.59 10.03     F6V 63 0
143 BD+19 2089 SB* 08 43 48.1499799562 +18 48 02.696069912   10.66 10.19     F8 56 0
144 BD+20 2201 SB* 08 44 37.0335825691 +19 42 39.137636008   11.06 10.43     G0 43 0
145 BD+20 2204 SB* 08 45 04.2274842409 +20 21 27.868771716   10.865 10.296     F5 47 0
146 Cl* NGC 2632 ANM 1471 ** 08 45 13.097088 +19 41 12.79824   11.602 10.848 10.726   G5 28 0
147 BD+22 1985 Ro* 08 45 27.9427195505 +21 39 12.920560001   11.16 10.52     F6.6 56 0
148 Cl* NGC 2632 JS 612 * 08 45 50.5725271872 +19 37 05.964291660   11.71 11.19     ~ 4 0
149 Cl* NGC 2632 JS 638 Ro* 08 46 47.3215888426 +19 38 41.023743473   11.303 10.701     G8V: 46 0
150 V* FV Cnc CV* 08 48 01.7386823727 +18 40 37.643532001   11.12 10.60     G4 63 0
151 Cl* NGC 2632 JS 660 Ro* 08 48 27.8391788767 +18 20 43.894506999   12.05 11.34     G5.3 40 0

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