J/AJ/162/153 X-ray properties of A,B-types, T-Tauri stars & YSOs (Nunez+, 2021)
Characterizing the X-ray emission of intermediate-mass pre-main-sequence stars.
Nunez E.H., Povich M.S., Binder B.A., Townsley L.K., Broos P.S.
<Astron. J., 162, 153-153 (2021)>
=2021AJ....162..153N 2021AJ....162..153N (SIMBAD/NED BibCode)
ADC_Keywords: Stars, A-type; Stars, B-type; Stars, pre-main sequence; YSOs;
X-ray sources; Stars, masses; Extinction
Keywords: Young stellar objects; Pre-main sequence stars; T Tauri stars
Single x-ray stars
Abstract:
We use X-ray and infrared observations to study the properties of
three classes of young stars in the Carina Nebula: intermediate-mass
(2-5M☉) pre-main-sequence stars (IMPS; i.e., intermediate-mass T
Tauri stars), late-B and A stars on the zero-age main sequence (AB),
and lower-mass T Tauri stars (TTS). We divide our sources among these
three subclassifications and further identify disk-bearing young
stellar objects versus diskless sources with no detectable infrared
(IR) excess emission using IR (1-8µm) spectral energy distribution
modeling. We then perform X-ray spectral fitting to determine the
hydrogen-absorbing column density (NH), absorption-corrected X-ray
luminosity (LX), and coronal plasma temperature (kT) for each
source. We find that the X-ray spectra of both IMPS and TTS are
characterized by similar kT and NH, and on average
LX/Lbol∼4x10-4. IMPS are systematically more luminous in X-rays
(by ∼0.3dex) than all other subclassifications, with median
LX=2.5x1031erg/s, while AB stars of similar masses have X-ray
emission consistent with TTS companions. These lines of evidence
converge on a magnetocoronal flaring source for IMPS X-ray emission, a
scaled-up version of the TTS emission mechanism. IMPS therefore
provide powerful probes of isochronal ages for the first ∼10Myr in the
evolution of a massive stellar population, because their intrinsic,
coronal X-ray emission decays rapidly after they commence evolving
along radiative tracks. We suggest that the most luminous (in both
X-rays and IR) IMPS could be used to place empirical constraints on
the location of the intermediate-mass stellar birth line.
Description:
The Chandra Carina Complex Project (CCCP) covered 1.42deg2 of the
Great Nebula in Carina with the Chandra X-ray Observatory
(Chandra/ACIS-I detector), revealing >10000 young stellar members as
X-ray point sources. In this paper we fit thermal plasma models to 370
of the brightest CCCP X-ray sources.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 236 370 X-ray and IR source properties
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See also:
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
II/293 : GLIMPSE Source Catalog (I + II + 3D) (IPAC 2008)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/ApJS/194/2 : Chandra Carina Complex Project (CCCP) catalog (Broos+, 2011)
J/ApJS/209/32 : Probable young stars in the MYStIX project (Broos+, 2013)
J/ApJ/787/108 : Age estimates massive SFR stellar populations (Getman+, 2014)
J/A+A/603/A81 : Trumpler 14 and 16 in the Carina nebula (Damiani+, 2017)
J/A+A/622/A72 : Intermediate-mass T Tau stars spectra (Villebrun+, 2019)
J/A+A/624/A137 : Stellar models and isochrones (Haemmerle+, 2019)
J/A+A/648/A34 : KMOS O-type star detection in Tr 16-SE (Preibisch+, 2021)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- ID IAU source identifier;
CXOGNC JHHMMSS.ss+DDMMSS.s (1)
20- 44 A25 --- MIR Spitzer MIR Vela-Carina source name
46- 55 F10.6 deg RAdeg [160/163] Right Ascension (J2000)
57- 66 F10.6 deg DEdeg [-61/60] Declination (J2000)
68- 71 A4 --- Class Temperature-Mass classification (2)
73 A1 --- YSO YSO source code; Section 2.1
75 A1 --- Frozen NH frozen to mean IR AV code; Section 2.5
77- 88 A12 --- Dof C-Statistic/Degrees of Freedom (3)
90- 96 F7.2 ct Full The 0.5-8keV net counts
98 I1 --- Var [0/2] Variable code (4)
100-109 F10.5 --- Area [1.23/1137] Average aperture area
(0.492arcsec2)
111-115 F5.2 arcmin Theta [0.22/10.2] Chandra off axis angle
117-120 F4.2 Msun Mass [0.19/8.88] Mass from SED
122-126 F5.3 Msun e_Mass [0.005/3] Weighted uncertainty in Mass
128-133 F6.3 10+22/cm2 NH [0.07/33] XSPEC hydrogen absorbing column
135-140 F6.3 10+22/cm2 b_NH [0.08/24.1]? 90% lower confidence on NH
142-146 F5.3 10+22/cm2 B_NH [0.22/9.76]? 90% upper confidence on NH
148 A1 --- AVSED AV from SED code; Section 3.1
150-157 F8.2 mag AV [0/69259]? Mean on extinction AV (5)
159-166 F8.2 mag b_AV [-1.6/69259]? Weighted lower bound on AV
168-177 F10.2 mag B_AV [1.2/1.04e+6]? Weighted upper bound on AV
179-179 A1 --- 2TMod Source fit with 2 temperature plasma model?
181-185 F5.2 keV kT [0.69/10.1] The plasma temperature (6)
187-190 F4.2 keV b_kT [0.29/5.35]? 90% lower confidence on kT
192-195 F4.2 keV B_kT [1.01/8.7]? 90% upper confidence on kT
197-204 E8.2 mW/m2 FxHc [6.9e-16/2.1e-12] Hard 2-8keV band
absorption corrected flux ; in erg/s/cm2
206-213 E8.2 mW/m2 FxTc [4.9e-15/3.1e-12] Total 0.5-8keV band
absorption corrected flux ; in erg/s/cm2
215-219 F5.2 [10-7W] logLxHc [29.7/33.2] log hard 2-8keV band absorption
corrected luminosity; in erg/s
221-225 F5.2 [10-7W] e_logLxHc [30/34] Uncertainty in logLxHc; in erg/s
227-231 F5.2 [Lsun] logLb [-0.03/3.61] log bolometric luminosity from
IR SED
233-236 F4.2 [Lsun] e_logLb [0/1.6] Weighted uncertainty in logLb
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Note (1): Prefix is CXOGNC J(Chandra X-ray) Observatory Great Nebula in Carina.
Note (2): Classes as follows:
AB = late-B and A-type (35 occurrences)
IMPS = pre-main-sequence stars (54 occurrences)
RIMP = partially radiative IMPS (23 occurrences)
TTS = T Tauri stars (176 occurrences)
unc = unclassified (82 occurrences)
Note (3): For X-ray spectral fit.
Note (4): Code as follows:
0 = non-variable (216 occurrences)
1 = possible variable (51 occurrences)
2 = definite variable (103 occurrences)
Note (5): When AvSED=y, Av from SED fit displayed. Else, AV from NIR estimate
is displayed.
Note (6): When 2TMod=y, kT2 is displayed.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 20-Jan-2022