2000ApJ...538..777E


Query : 2000ApJ...538..777E

2000ApJ...538..777E - Astrophys. J., 538, 777-782 (2000/August-1)

Settling onto the main sequence: ROSAT observations of h and χ Persei.

EVANS N.R. and SEWARD F.D.

Abstract (from CDS):

We have studied X-rays from the double cluster h and χ Per with an 11 ks ROSAT position-sensitive proportional counter (PSPC) observation. Emission is concentrated toward the two cluster centers. Whether the emission is diffuse emission or from a population of unresolved faint sources is uncertain because the resolution is poor at the distance of the clusters (2.4 kpc). Twenty-three sources were found with an X-ray luminosity of logL=31.5 ergs.s–1 or greater. These sources were found in the cluster nuclei, between the clusters, and in a halo around the cluster pair. The ROSAT PSPC error circle is too large for the identification of X-ray sources with individual optical objects. However, because of a lack of correlation between X-ray sources and B stars, we conclude that the X-rays are produced by late spectral type pre-main-sequence stars. The X-ray sources are brighter than all but the very brightest sources in the younger Orion Nebula cluster, which makes them important in tracing the final stages approaching the main sequence.

Abstract Copyright: ∼

Journal keyword(s): open clusters and associations: individual (χ Persei, h Persei) - Stars: Formation - Stars: Pre-Main-Sequence - X-Rays: Stars

Nomenclature: Table 1: [ES2000] NN (Nos 1-26).

Simbad objects: 35

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Number of rows : 35
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 1RXS J021639.3+564406 X 02 16 40 +56 44.1           ~ 1 0
2 [ES2000] 3 X 02 17 40 +57 15.2           ~ 1 0
3 * chi Per * 02 18 04.5845635872 +57 30 58.759401204   7.036 6.0230     G7.0III 179 1
4 [ES2000] 23 X 02 18 10 +56 51.6           ~ 1 0
5 [ES2000] 2 X 02 18 16 +57 13.7           ~ 1 0
6 [ES2000] 8 X 02 18 31 +56 59.1           ~ 1 0
7 [ES2000] 1 X 02 18 36 +57 10.8           ~ 1 0
8 [ES2000] 7 X 02 18 48 +57 01.4           ~ 1 0
9 [ES2000] 9 X 02 18 56 +57 06.9           ~ 1 0
10 NGC 869 OpC 02 18 57.0 +57 08 02           ~ 504 0
11 [ES2000] 10 X 02 18 57 +57 08.4           ~ 1 0
12 [ES2000] 13 X 02 18 59 +57 08.2           ~ 1 0
13 [ES2000] 11 X 02 19 08 +57 08.1           ~ 1 0
14 [ES2000] 6 X 02 19 25 +56 59.8           ~ 1 0
15 [ES2000] 5 X 02 19 41 +57 06.2           ~ 1 0
16 [ES2000] 12 X 02 19 51 +57 00.0           ~ 1 0
17 [ES2000] 4 X 02 20 08 +57 07.4           ~ 1 0
18 [ES2000] 14 X 02 20 38 +57 08.7           ~ 1 0
19 [ES2000] 15 X 02 20 53 +57 04.9           ~ 1 0
20 [ES2000] 16 X 02 21 11 +57 01.0           ~ 1 0
21 [ES2000] 17 X 02 21 33 +57 08.4           ~ 1 0
22 [ES2000] 21 X 02 21 51 +56 54.4           ~ 1 0
23 HD 14434 Em* 02 21 52.4121560832 +56 54 18.032028876 7.87 8.65 8.49 8.29 8.20 O5.5Vnn((f))p 198 0
24 [ES2000] 22 X 02 21 55 +56 43.3           ~ 1 0
25 [ES2000] 19 X 02 21 56 +57 06.0           ~ 1 0
26 [ES2000] 20 X 02 22 04 +57 06.8           ~ 1 0
27 [ES2000] 18 X 02 22 04 +57 06.9           ~ 1 0
28 NGC 884 OpC 02 22 15.7 +57 08 59           ~ 503 0
29 [ES2000] 26 X 02 23 30 +56 54.6           ~ 1 0
30 Cl Melotte 20 MGr 03 26 50.6 +48 51 48           ~ 928 0
31 Cl Melotte 22 OpC 03 46 38.0 +24 10 41           ~ 3679 0
32 NAME Ori Region reg 05 35 17.30 -05 23 28.0           ~ 623 0
33 IC 2391 OpC 08 41 17.5 -53 03 00           ~ 871 0
34 IC 2602 OpC 10 42 55.9 -64 25 22           ~ 735 0
35 NAME Chamaeleon Region SFR 11 55 -78.0           ~ 887 0

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