Astrophys. J., 589, 509-525 (2003/May-3)
Chandra observations of associates of η Carinae. I. Luminosities.
EVANS N.R., SEWARD F.D., KRAUSS M.I., ISOBE T., NICHOLS J., SCHLEGEL E.M. and WOLK S.J.
Abstract (from CDS):
The region around the η Carinae Nebula has three OB associations, which contain a Wolf-Rayet star and several massive O3 stars. An early Chandra ACIS-I image was centered on η Car and includes Trumpler 16 and part of Trumpler 14. The Chandra image confirms the well-known result that O and very early B stars are X-ray sources with LX≃10–7Lbolover an X-ray luminosity range of about 100. Two new, anomalously strong X-ray sources have been found among the hot star population: Tr 16-244, a heavily reddened O3 I star, and Tr 16-22, a heavily reddened O8.5 V star. Two stars have an unusually large LX/Lbol: HD 93162, a Wolf-Rayet star (and possible binary), and Tr 16-22, a possible colliding-wind binary. In addition, a population of sources associated with cool stars is detected. In the color-magnitude diagram, these X-ray sources sit above the sequence of field stars in the Carina arm. The OB stars are on average more X-ray-luminous than the cool star X-ray sources. X-ray sources among A stars have X-ray luminosities similar to those of cooler stars and may be due to cooler companions. Upper limits are presented for B stars that are not detected in X-rays. These upper limits are also the upper limits for any cool companions that the hot stars may have. Hardness ratios are presented for the most luminous sources in bands 0.5-0.9, 0.9-1.5, and 1.5-2.04 keV. The available information on the binary nature of the hot stars is discussed, but binarity does not correlate with X-ray strength in a simple way.
Galaxy: Open Clusters and Associations: Individual: Name: Trumpler 14 - Galaxy: Open Clusters and Associations: Individual: Name: Trumpler 16 - X-Rays: Stars
VizieR on-line data:
<Available at CDS (J/ApJ/589/509): tab12.dat tab34.dat table5.dat tab68.dat table7.dat>
Tables 1, 2: [ESK2003] NNN N=154 among (Nos 1-167). Table 7: [ESK2003] NotDetected NN N=23 among (Nos 1-32).
Status at CDS:
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