2002ApJ...578..486D

Query : 2002ApJ...578..486D

2002ApJ...578..486D - Astrophys. J., 578, 486-502 (2002/October-2)

Chandra observations of the Pleiades open cluster: X-ray emission from late B- to early F-type binaries.

DANIEL K.J., LINSKY J.L. and GAGNE M.

Abstract (from CDS):

We present the analysis of a 38.4 and 23.6 ks observation of the core of the Pleiades open cluster. The Advanced CCD Imaging Spectrometer on board the Chandra X-Ray Observatory detected 99 X-ray sources in a 17'x17' region, including 18 of 23 Pleiades members. Five candidate Pleiades members have also been detected, confirming their cluster membership. Fifty-seven sources have no optical or near-infrared counterparts to limiting magnitudes V=22.5 and J=14.5. The unidentified X-ray sources are probably background active galactic nuclei and not stars. The Chandra field of view contains seven intermediate-mass cluster members. Five of these, HII 980 (B6+G), HII 956 (A7+F6), HII 1284 (A9+K), HII 1338 (F3+F6), and HII 1122 (F4+K), are detected in this study. All but HII 1284 have high X-ray luminosity and soft X-ray spectra. HII 1284 has X-ray properties comparable to nonflaring K-type stars. Since all five stars are visual or spectroscopic binaries with X-ray properties similar to F-G stars, the late-type binary companions are probably producing the observed coronal X-ray emission. Strengthening this conclusion is the nondetection by Chandra of two A stars, HII 1362 (A7, no known companion) and HII 1375 (A0+A SB) with X-ray luminosity upper limits 27-54 times smaller than HII 980 and HII 956, the B6-A7 stars with cooler companions. Despite the low number statistics, the Chandra data appear to confirm the expectation that late B and A stars are not strong intrinsic X-ray sources. The ACIS spectra and hardness ratios suggest a gradual increase in coronal temperature with decreasing mass from F4 to K. M stars appear to have somewhat cooler coronae than active K stars.

Abstract Copyright: ∼

Journal keyword(s): Galaxy: Open Clusters and Associations: Individual: Name: Pleiades - Stars: Activity - Stars: Coronae - Stars: Early-Type - X-Rays: Stars

Nomenclature: Table 1: CXOP JHHMMSS.s+DDMMSS N=99.

Simbad objects: 103

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Number of rows : 103
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 Cl* Melotte 22 BPL 88 Er* 03 46 04.5633356639 +24 09 56.040778264         15.83 ~ 25 0
2 CXOP J034609.9+240541 X 03 46 09.92 +24 05 41.7           ~ 1 0
3 CXOP J034610.0+240954 X 03 46 10.01 +24 09 54.6           ~ 1 0
4 CXOP J034612.5+240347 X 03 46 12.60 +24 03 47.3           ~ 1 0
5 V* V1189 Tau BY* 03 46 12.8676359335 +24 03 15.754257358   15.59 14.22   12.48 M1.4 63 0
6 HD 23479 Er* 03 46 16.0035787584 +24 11 23.722659996   8.91 8.80 8.72 7.57 A7V 107 0
7 CXOP J034617.6+240110 X 03 46 17.61 +24 01 10.2           ~ 1 0
8 CXOP J034619.4+235628 X 03 46 19.42 +23 56 29.2           ~ 2 0
9 * 23 Tau Be* 03 46 19.5858871361 +23 56 54.092177220 3.70 4.12 4.18   4.16 B6IV(e) 432 2
10 CXOP J034620.1+240028 X 03 46 20.10 +24 00 28.8           ~ 1 0
11 CXOP J034620.8+235858 X 03 46 20.85 +23 58 58.5           ~ 1 0
12 CXOP J034623.4+240856 X 03 46 23.42 +24 08 56.9           ~ 1 0
13 V* V528 Tau Er* 03 46 23.4665085267 +24 01 51.397679361     18.50   15.10 ~ 34 0
14 CXOP J034623.6+235538 Q? 03 46 23.64 +23 55 38.9           ~ 1 0
15 Cl Melotte 22 OpC 03 46 24.2 +24 06 50           ~ 3433 0
16 CXOP J034624.3+235958 X 03 46 24.38 +23 59 58.5           ~ 1 0
17 CXOP J034624.8+240126 X 03 46 24.88 +24 01 27.0           ~ 1 0
18 V* OZ Tau Er* 03 46 25.3897599128 +24 09 36.475521778   17.09 16.05 15.59 13.37 M3.1 56 0
19 CXOP J034627.9+235532 Q? 03 46 27.95 +23 55 32.1           ~ 1 0
20 CXOP J034628.1+235753 X 03 46 28.13 +23 57 53.7           ~ 1 0
21 LAMOST J034629.03+235822.3 * 03 46 29.04 +23 58 22.2           ~ 2 0
22 CXOP J034629.1+240839 Q? 03 46 29.18 +24 08 39.9           ~ 1 0
23 CXOP J034629.5+240042 X 03 46 29.53 +24 00 42.8           ~ 1 0
24 CXOP J034630.0+235740 X 03 46 30.01 +23 57 40.1           ~ 1 0
25 Cl* Melotte 22 SRS 64413 Er* 03 46 30.2320249920 +24 05 07.660248468       16.411   ~ 3 0
26 CXOP J034630.3+240853 X 03 46 30.35 +24 08 53.7           ~ 1 0
27 CXOP J034630.5+235546 X 03 46 30.59 +23 55 46.9           ~ 1 0
28 CXOP J034630.8+241124 X 03 46 30.85 +24 11 24.1           ~ 1 0
29 V* PP Tau Y*O 03 46 31.1851066172 +24 07 02.431428754   15.60 14.21   12.39 M1.6 75 0
30 CXOP J034632.0+240746 X 03 46 32.01 +24 07 46.5           ~ 1 0
31 V* PQ Tau Er* 03 46 32.1220179264 +23 58 58.752905988   14.30       K7 19 0
32 CXOP J034632.4+240547 X 03 46 32.42 +24 05 47.7           ~ 1 0
33 CXOP J034634.0+240146 X 03 46 34.01 +24 01 46.0           ~ 1 0
34 CXOP J034634.8+240728 X 03 46 34.88 +24 07 28.8           ~ 1 0
35 Cl* Melotte 22 DH 458 Er* 03 46 35.5305948311 +24 01 35.525924494     19.00   15.40 MV 25 0
36 CXOP J034635.7+240754 X 03 46 35.73 +24 07 54.5           ~ 1 0
37 V* V448 Tau Y*O 03 46 35.9117232840 +23 58 01.275542652   15.42 14.02     M1.5 48 0
38 USNO-A2.0 1125-01262204 * 03 46 38.8236369984 +23 58 03.959776632   17.3       ~ 1 0
39 HD 23511 PM* 03 46 39.3335012425 +24 06 11.531508492   9.75 9.28   8.75 F5V 125 0
40 V* V814 Tau BY* 03 46 39.3864483531 +24 01 46.867039992   13.04 12.13   11.24 K3V 100 0
41 CXOP J034640.8+240746 X 03 46 40.89 +24 07 46.1           ~ 1 0
42 CXOP J034641.3+240426 X 03 46 41.33 +24 04 26.4           ~ 1 0
43 CXOP J034641.8+240351 X 03 46 41.88 +24 03 51.8           ~ 1 0
44 Cl* Melotte 22 DH 467 Er* 03 46 43.5895860823 +23 59 42.497999718   17.667 16.120   13.771 M2.8 43 0
45 CXOP J034643.6+240120 * 03 46 43.65 +24 01 20.5   19.7       ~ 1 0
46 CXOP J034644.0+235911 X 03 46 44.05 +23 59 11.5           ~ 1 0
47 CXOP J034644.1+240218 X 03 46 44.19 +24 02 18.6           ~ 1 0
48 CXOP J034644.5+240122 X 03 46 44.50 +24 01 22.2           ~ 1 0
49 CXOP J034646.0+235750 X 03 46 46.02 +23 57 50.3           ~ 1 0
50 CXOP J034646.6+240757 Q? 03 46 46.65 +24 07 57.6           ~ 1 0
51 CXOP J034647.2+240128 Q? 03 46 47.27 +24 01 28.7           ~ 1 0
52 CXOP J034647.9+240601 X 03 46 48.00 +24 06 01.9           ~ 1 0
53 CXOP J034648.1+240334 X 03 46 48.11 +24 03 34.1           ~ 1 0
54 CXOP J034648.5+240039 X 03 46 48.59 +24 00 39.5           ~ 1 0
55 CXOP J034649.1+240833 Q? 03 46 49.11 +24 08 33.0           ~ 1 0
56 [KRL2001] 21 PM* 03 46 51.4282819008 +24 06 16.285800132           ~ 12 0
57 CXOP J034651.4+235953 X 03 46 51.49 +23 59 54.0           ~ 1 0
58 CXOP J034652.0+240005 Q? 03 46 52.00 +24 00 05.2           ~ 1 0
59 CXOP J034652.1+240850 X 03 46 52.14 +24 08 50.7           ~ 1 0
60 CXOP J034652.8+240338 X 03 46 52.88 +24 03 38.9           ~ 1 0
61 CXOP J034652.9+240037 X 03 46 52.99 +24 00 37.6           ~ 1 0
62 CXOP J034653.0+235656 Q? 03 46 53.03 +23 56 56.4           ~ 1 0
63 CXOP J034653.6+240325 X 03 46 53.63 +24 03 25.2           ~ 1 0
64 Cl* Melotte 22 MHO 8 Er* 03 46 53.9572109375 +24 07 57.243630147     18.92     MV 25 0
65 UCAC4 571-008667 * 03 46 54.4235012304 +24 06 42.656259564   15.73 14.51 14.09   ~ 3 0
66 CXOP J034655.0+240033 X 03 46 55.02 +24 00 34.0           ~ 1 0
67 Cl* Melotte 22 DH 478 * 03 46 55.3101893022 +24 11 16.777819565     19.02   15.68 MV 31 0
68 CXOP J034655.3+240024 X 03 46 55.39 +24 00 24.5           ~ 1 0
69 CXOP J034655.7+240151 X 03 46 55.76 +24 01 51.5           ~ 1 0
70 Cl* Melotte 22 DH 480 * 03 46 55.7755673496 +23 56 24.215121456     18.40   14.70 M5 19 0
71 CXOP J034657.1+240337 X 03 46 57.10 +24 03 37.5           ~ 1 0
72 CXOP J034657.3+240612 X 03 46 57.35 +24 06 12.9           ~ 1 0
73 2MASS J03465825+2401415 Er* 03 46 58.2568973467 +24 01 41.478164358           M5 21 0
74 Cl* Melotte 22 DH 484 Er* 03 46 59.3116640184 +24 01 42.916021104   19.90 17.60   14.40 M4.1 41 0
75 CXOP J034659.9+240132 X 03 46 59.92 +24 01 32.1           ~ 1 0
76 CXOP J034700.7+241322 X 03 47 00.76 +24 13 22.3           ~ 1 0
77 CXOP J034701.2+240206 X 03 47 01.30 +24 02 06.0           ~ 1 0
78 CXOP J034701.5+241047 X 03 47 01.58 +24 10 47.5           ~ 1 0
79 Cl* Melotte 22 BPL 122 Er* 03 47 01.8400266336 +24 13 28.281607500     20.18   16.87 M 20 0
80 V* V535 Tau Y*O 03 47 03.5824795963 +24 09 34.870154100   15.93 14.58   12.72 M2.4 75 0
81 V* V1210 Tau gD* 03 47 04.2131220000 +23 59 42.773483436   8.67 8.38   8.02 F0V 121 0
82 CXOP J034704.7+235748 X 03 47 04.80 +23 57 48.3           ~ 1 0
83 CXOP J034705.4+240608 X 03 47 05.42 +24 06 08.7           ~ 1 0
84 CXOP J034705.9+235943 X 03 47 05.91 +23 59 43.5           ~ 1 0
85 CXOP J034707.5+241013 Q? 03 47 07.54 +24 10 13.7           ~ 1 0
86 Cl* Melotte 22 VM 21 Er* 03 47 09.1825214756 +24 03 07.822324545   18.33 16.52     ~ 31 0
87 CXOP J034709.6+240146 Q? 03 47 09.69 +24 01 46.6           ~ 1 0
88 CXOP J034710.1+240623 X 03 47 10.17 +24 06 23.5           ~ 1 0
89 V* QS Tau Er* 03 47 11.0206425648 +24 13 51.651060420   14.00 19.34   16.03 ~ 37 0
90 2MASS J03471124+2406465 X 03 47 11.2523156184 +24 06 46.477386972           ~ 1 0
91 CXOP J034711.7+240652 X 03 47 11.76 +24 06 52.9           ~ 1 0
92 Cl* Melotte 22 BPL 130 * 03 47 11.8075281312 +24 13 30.734361588     21.44   16.98 M 12 0
93 Cl* Melotte 22 DH 499 * 03 47 11.8585895352 +24 13 53.882810868     19.52   15.89 ~ 27 0
94 CXOP J034712.5+240112 X 03 47 12.53 +24 01 12.3           ~ 1 0
95 CXOP J034712.7+240812 X 03 47 12.74 +24 08 12.2           ~ 1 0
96 2MASS J03471316+2400453 * 03 47 13.1676740232 +24 00 45.325175076   18.60       ~ 7 0
97 HD 23608 SB* 03 47 16.5764110218 +24 07 41.906506002   9.15 8.72   8.09 F3V 82 0
98 CXOP J034716.9+241233 X 03 47 16.90 +24 12 33.5           ~ 1 0
99 V* V646 Tau Y*O 03 47 18.147480 +24 02 11.34420   15.35 14.03 13.69 12.14 M1.5Ve 54 0
100 V* V647 Tau dS* 03 47 19.3458598776 +24 08 20.815318464   8.51 8.26   7.97 A7Vs 164 0
101 * 24 Tau * 03 47 21.0386292336 +24 06 58.564163952 6.26 6.30 6.28   6.30 A0V 89 0
102 CXOP J034722.6+240010 X 03 47 22.65 +24 00 10.2           ~ 1 0
103 2MASS J03472534+2402570 Y*O 03 47 25.3424655936 +24 02 56.964658812     16.1   13.79 M3.1 34 0

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