2007MNRAS.377..945S

Query : 2007MNRAS.377..945S

2007MNRAS.377..945S - Mon. Not. R. Astron. Soc., 377, 945-956 (2007/May-3)

An XMM-Newton view of the young open cluster NGC 6231 - III. Optically faint X-ray sources.

SANA H., RAUW G., SUNG H., GOSSET E. and VREUX J.-M.

Abstract (from CDS):

We discuss the properties of the X-ray sources with faint optical counterparts in the very young open cluster NGC 6231. From their positions in the Hertzsprung-Russell diagram, we find that the bulk of these objects probably consists of low-mass pre-main-sequence (PMS) stars with masses in the range 0.3-3.0 M☉. The age distribution of these objects indicates that low-mass star formation in NGC 6231 started more than 10Myr ago and culminated in a starburst-like event about 1-4Myr ago when the bulk of the low-mass PMS stars as well as the massive cluster members formed. We find no evidence for a spatial age gradient that could point towards a sequential star formation process. Only a few X-ray sources have counterparts with a reddening exceeding the average value of the cluster or with infrared colours indicating the presence of a moderate near-IR excess. The X-ray spectra of the brightest PMS sources are best fitted by rather hard thermal plasma models and a significant fraction of these sources display flares in their light curve. The X-ray brightest flaring sources have decay times between 2 and 16ks. The X-ray selected PMS stars in NGC 6231 have logLX/Lbol values that increase strongly with decreasing bolometric luminosity and can reach a saturation level (logLX/Lbol∼ -2.4) for non-flaring sources and even more extreme values during flares.

Abstract Copyright: 2007 The Authors. Journal compilation © 2007 RAS

Journal keyword(s): stars: pre-main-sequence - Open clusters and associations: individual: NGC 6231 - X-rays: individual: NGC 6231 - X-rays: stars

Simbad objects: 38

goto Full paper

goto View the references in ADS

Number of rows : 38
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 NAME Sco OB 1 As* 16 53.5 -41 57           ~ 222 0
2 2XMM J165334.4-414423 X 16 53 34.4 -41 44 23           ~ 5 0
3 [SGR2006] 43 X 16 53 34.52 -41 58 58.2           ~ 3 0
4 2MASS J16533586-4138072 Y*? 16 53 35.8653361104 -41 38 07.307598768           ~ 5 0
5 [SGR2006] 100 X 16 53 48.33 -41 40 08.6   18.8   17.4   ~ 3 0
6 XMMU J165354.7-415303 X 16 53 54.61 -41 53 03.6           ~ 3 0
7 NGC 6231 256 * 16 53 58.04 -41 52 20.1 16.600 16.104 14.988   13.617 ~ 6 0
8 2MASS J16535872-4146434 Y*? 16 53 58.729 -41 46 43.44   19.571 18.153   16.057 ~ 4 0
9 Cl* NGC 6231 SBL 279 Y*O 16 53 59.5861851384 -41 48 01.777743504 16.799 16.010 14.772   13.443 ~ 9 0
10 2MASS J16540011-4147396 Y*? 16 54 00.1177966368 -41 47 39.589417392 13.289 13.279 12.925   12.367 B 9 0
11 Cl* NGC 6231 SBL 304 Y*O 16 54 01.8086489760 -41 43 34.418432604 17.485 16.842 15.680   14.196 ~ 10 0
12 V* V1200 Sco gD* 16 54 04.9315146528 -41 56 45.691087488 17.541 16.930 15.713   14.225 ~ 10 0
13 XMMU J165406.0-414509 X 16 54 05.8414317504 -41 45 08.202359304           ~ 3 0
14 2MASS J16540640-4145432 Y*? 16 54 06.3934019832 -41 45 43.304847876   18.018 16.592   14.754 ~ 6 0
15 2MASS J16540710-4150000 Y*? 16 54 07.1063502912 -41 49 59.976087348 14.321 13.909 13.287   12.463 ~ 8 0
16 [SGR2006] 258 X 16 54 07.36 -41 51 56.9           ~ 3 0
17 NGC 6231 314 Be* 16 54 08.779 -41 51 49.47 12.600 12.613 12.216   11.639 Be 8 0
18 2MASS J16541081-4139177 * 16 54 10.8079743312 -41 39 17.690937660           ~ 3 0
19 Cl* NGC 6231 SBL 405 Y*? 16 54 11.5053349920 -41 50 05.954921700 16.919 16.530 15.513   14.277 ~ 7 0
20 Cl* NGC 6231 MG 200 * 16 54 12.39 -41 51 22.7 12.999 13.078 12.754   12.260 ~ 4 0
21 Cl* NGC 6231 SS 95 Y*? 16 54 13.1368344000 -41 45 05.543454456 13.639 13.574 13.230   12.761 ~ 11 0
22 NGC 6231 OpC 16 54 14.4 -41 48 53           ~ 562 0
23 2MASS J16541514-4150210 Y*? 16 54 15.146 -41 50 21.03 17.385 16.801 15.572   14.097 ~ 5 0
24 2MASS J16541736-4148294 Y*? 16 54 17.3634089088 -41 48 29.394925740 13.250 12.914 12.424   11.679 ~ 9 0
25 Cl* NGC 6231 SBL 550 Y*? 16 54 23.8739156976 -41 50 16.141912548 17.048 16.463 15.370   13.927 ~ 8 0
26 USNO-B1.0 0481-00503587 X 16 54 29.24 -41 50 47.7   13.0   14.9   ~ 3 0
27 2MASS J16543187-4151076 Y*? 16 54 31.8737507424 -41 51 07.556393232   19.765 18.331   16.301 ~ 6 0
28 2MASS J16543204-4151549 Y*? 16 54 32.043 -41 51 54.95   18.703 17.242   15.423 ~ 5 0
29 V* V1213 Sco gD* 16 54 33.3548087280 -41 56 32.458697880 16.897 16.291 14.960   13.538 ~ 12 0
30 2MASS J16544261-4149582 Y*O 16 54 42.6109625256 -41 49 58.584865296           ~ 8 0
31 2MASS J16544525-4152446 Y*? 16 54 45.2528303712 -41 52 44.686679340 14.439 14.163 13.590   12.800 ~ 10 0
32 2MASS J16545054-4202003 Y*? 16 54 50.5382896512 -42 02 00.319231536           ~ 4 0
33 2MASS J16545664-4201566 * 16 54 56.6329198848 -42 01 56.607387240   14.5   13.4   ~ 3 0
34 VPHAS J165512.2-414630.2 Y*? 16 55 12.1747062120 -41 46 29.989710480           ~ 5 0
35 NGC 6383 OpC 17 34 41.6 -32 34 27           ~ 168 0
36 HD 159176 Be* 17 34 42.4921337376 -32 34 53.995451196 4.88 5.74 5.70 7.19   O7V 261 0
37 M 8 OpC 18 03 37 -24 23.2           ~ 644 1
38 NGC 6530 OpC 18 04 31 -24 21.5           ~ 443 0

To bookmark this query, right click on this link: simbad:objects in 2007MNRAS.377..945S and select 'bookmark this link' or equivalent in the popup menu