J/A+A/587/A81 T Tauri stars X-ray/accretion anti correlation (Bustamante+, 2016)
X-ray deficiency on strongly accreting T Tauri stars.
Comparing Orion with Taurus.
Bustamante I., Merin B., Bouy H., Manara C., Ribas A., Rivere-Marichalar P.
<Astron. Astrophys. 587, A81 (2016)>
=2016A&A...587A..81B 2016A&A...587A..81B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, pre-main sequence ; X-ray sources ; Stars, masses
Keywords: planetary systems - X-ray stars - stars: pre-main sequence -
protoplanetary disks
Abstract:
Depending on whether a T Tauri star accretes material from its
circumstellar disk or not, different X-ray emission properties can be
found. The accretion shocks produce cool heating of the plasma,
contributing to the soft X-ray emission from the star. Using X-ray
data from the Chandra Orion Ultra-deep Project and accretion rates
that were obtained with the Hubble Space Telescope/WFPC2 photometric
measurements in the Orion Nebula Cluster, we studied the relation
between the accretion processes and the X-ray emissions of a coherent
sample of T Tauri sources in the region. We performed regression and
correlation analyses of our sample of T Tauri stars between the X-ray
parameters, stellar properties, and the accretion measurements. We
find that a clear anti-correlation is present between the residual
X-ray luminosity and the accretion rates in our samples in Orion that
is consistent with that found on the XMM-Newton Extended Survey of the
Taurus molecular cloud (XEST) study. A considerable number of
classified non-accreting sources show accretion rates comparable to
those of classical T Tauri Stars (CTTS). Our data do not allow us to
confirm the classification between classical and weak-line T Tauri
stars (WTTS), and the number of WTTS in this work is small compared to
the complete samples. Thus, we have used the entire samples as
accretors in our analysis. We provide a catalog with X-ray
luminosities (corrected from distance) and accretion measurements of
an Orion Nebula Cluster (ONC) T Tauri stars sample.
Description:
Stellar parameters and derived X-ray residual luminosities are
presented. Two different subsamples are shown in the table, depending
whether the accretion rates were computed using an excess in the U
band or using the equivalent width of the Halpha line. Three
different sources are used for these data: X-ray information from the
Chandra Orion Ultradeep Project (COUP), stellar information from
Manara et al. (2012, Cat. J/ApJ/755/154) and properties derived in
this work. For each source identification, coordinates and X-ray
luminosity (logarithmic) from COUP, identification, coordinates,
stellar mass, mass accretion rate and spectral type from Manara et al.
(2012, Cat. J/ApJ/755/154) and residual X-ray luminosity derived from
this work is given. This last parameter depends on the relations
between X-ray luminosity, stellar mass and mass accretion rate derived
in this work.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
sphalpha.dat 132 277 Stellar parameters of sources which mass accretion
rates were derived using the equivalent width
of the Hα line (table 4a)
sp2cd.dat 132 154 Stellar parameters of sources which mass accretion
rates were derived using excesses in the U band
(table 4b)
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See also:
J/ApJ/755/154 : Mass accretion rates from HST in the ONC (Manara+, 2012)
J/ApJS/160/319 : COUP: observations and source lists (Getman+, 2005)
Byte-by-byte Description of file: sphalpha.dat sp2cd.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- COUP Identification number from COUP catalog
6- 12 F7.4 deg RAdeg Right ascension (J2000) from COUP catalog
15- 21 F7.4 deg DEdeg Declination (J2000) from COUP catalog
23- 30 F8.5 [10-7W] logLX Logarithmic X-ray luminosity from
COUP catalog
32- 38 F7.5 [10-7W] e_logLX Logarithmic X-ray luminosity uncertainty
from COUP catalog
40- 43 I4 --- OM Identification number from Manara et al.
(2012, Cat. J/ApJ/755/154,
[MRD2012] NNNN in SImbad)
45- 51 F7.4 deg RA2deg Right ascension (J2000) from Manara et al.
(2012, Cat. J/ApJ/755/154)
54- 60 F7.4 deg DE2deg Declination (J2000) from Manara et al.
(2012, Cat. J/ApJ/755/154)
62- 69 F8.5 [Msun] logM* Logarithmic stellar mass from Manara et al.
(2012, Cat. J/ApJ/755/154)
71- 77 F7.5 [Msun] e_logM* Logarithmic stellar mass uncertainty from
Manara et al. (2012, Cat. J/ApJ/755/154)
79- 87 F9.5 [Msun/yr] logMacc Logarithmic mass accretion rate from
Manara et al. (2012, Cat. J/ApJ/755/154)
89- 95 F7.5 [Msun/yr] e_logMacc Logarithmic mass accretion rate uncertainty
from Manara et al. (2012, J/ApJ/755/154)
97- 98 A2 --- SpType MK spectral Type from Manara et al.
(2012, Cat. J/ApJ/755/154)
100-107 F8.5 --- RLXols Residual X-ray luminosity using the ordinary
least square method (logLX/LX(Macc))
109-115 F7.5 --- e_RLXols Residual X-ray luminosity uncertainty using
the ordinary least square method
117-124 F8.5 --- RLXout Residual X-ray luminosity using outlier
rejection method (logLX/LX(Macc))
126-132 F7.5 --- e_RLXout Residual X-ray luminosity uncertainty using
outlier rejection method
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Acknowledgements:
Ignacio Bustamante, ibustamante(at)cab.inta-csic.es
(End) Patricia Vannier [CDS] 15-Dec-2015