J/ApJ/660/1462 Abundances of ONC X-ray PMS stars (Maggio+, 2007)
Coronal abundances in Orion nebula cluster stars.
Maggio A., Flaccomio E., Favata F., Micela G., Sciortino S.,
Feigelson E.D., Getman K.V.
<Astrophys. J., 660, 1462-1479 (2007)>
=2007ApJ...660.1462M 2007ApJ...660.1462M
ADC_Keywords: Clusters, open; X-ray sources ; Stars, pre-main sequence ;
Photometry ; Abundances
Keywords: stars: activity - stars: coronae - stars: late-type - X-rays: stars
Abstract:
Following the Chandra Orion Ultradeep Project (COUP) observation, we
have studied the chemical composition of the hot plasma in a sample of
146 X-ray-bright pre-main-sequence stars in the Orion Nebula Cluster
(ONC). We report measurements of individual element abundances for a
subsample of 86 slightly absorbed and bright X-ray sources, using
low-resolution X-ray spectra obtained from the Chandra ACIS
instrument.
Description:
The COUP data were obtained in 2003 January with the Advanced CCD
Imaging Spectrometer (ACIS) on board the Chandra X-Ray Observatory by
combining six consecutive observations of the Orion Nebula Cluster
(ONC) with the same aim point and roll angle. The resulting data set
has a total exposure time of ∼838ks (9.7days), distributed over
13.2days.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 84 146 Properties of Sample Stars
table2.dat 82 86 Spectral Analysis Results
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See also:
J/ApJS/160/319 : COUP: observations and source lists (Getman+, 2005)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 A1 --- S [HL] (L)ow- or (H)igh-Absorption Sample
3- 6 I4 --- COUP COUP number (Cat. J/ApJS/160/319)
8- 21 A14 --- SpType Spectral type
23- 26 F4.2 solMass Mass ?=- Stellar Mass
28- 31 F4.2 [yr] Age ?=- Stellar Age (log scale)
33- 36 F4.2 mag AV ?=- Absorption in V band
38- 42 F5.2 mag D(I-K) ?=- Δ(I-K) near-infrared excess
44- 48 F5.1 0.1nm EW ?=- Ca II equivalent width
50- 54 F5.2 mag Vmag ?=- V magnitude
56- 60 F5.2 mag Imag ?=- I magnitude
62- 66 F5.2 mag Jmag ?=- J magnitude
68- 72 F5.2 mag Hmag ?=- H magnitude
74- 78 F5.2 mag Ksmag ?=- Ks magnitude
80- 84 F5.2 mag Lmag ?=- L magnitude
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- COUP COUP number (Cat. J/ApJS/160/319)
6- 8 F3.1 10+21cm-2 NH Interstellar absorption H column density
10- 12 F3.1 keV T1 ?=- Plasma temperature of the first component
14- 16 F3.1 keV T2 Plasma temperature of the second component
18- 21 F4.1 keV T3 Plasma temperature of the third component
23- 25 F3.1 m-5 k1 ?=- Volume emission measure for the first
component, divided by 4πD2 (1)
27- 30 F4.1 m-5 k2 ?=- Volume emission measure for the second
component, divided by 4πD2 (1)
32- 34 F3.1 m-5 k3 ?=- Volume emission measure for the third
component, divided by 4πD2 (1)
36- 38 F3.1 Sun O O abundance (in solar units)
40- 42 F3.1 Sun Ne Ne abundance (in solar units)
44- 46 F3.1 Sun Mg Mg abundance (in solar units)
48- 50 F3.1 Sun Si Si abundance (in solar units)
52- 54 F3.1 Sun S S abundance (in solar units)
56- 58 F3.1 Sun Ar Ar abundance (in solar units)
60- 62 F3.1 Sun Ca Ca abundance (in solar units)
64- 66 F3.1 Sun Fe Fe abundance (in solar units)
68- 70 F3.1 Sun Ni Ni abundance (in solar units)
72- 74 F3.1 --- Rchi2 Reduced χ2
76- 78 I3 --- DOF Degrees of freedom
80- 82 F3.1 10-16W/m2 fX Absorbed source X-ray flux, in the 2-8keV
(hard) band, in 10-13erg/cm2/s
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Note (1): the volume emission measure is EM = n2V, where
n is the electron number density and V the volume;
D is the source distance. The result is in 10-10cm-5.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 13-Mar-2009