J/ApJ/935/43 X-ray Sources Towards 10 Open Clusters (Getman+, 2022)
Evolution of X-Ray Activity in <25 Myr Old Pre-main Sequence Stars.
Getman K.V., Feigelson E.D., Garmire G.P., Broos P.S., Kuhn M.A.,
Preibisch T., Airapetian V.S.
<Astrophys. J., 935, 43 (2022)>
=2022ApJ...935...43G 2022ApJ...935...43G
ADC_Keywords: X-ray sources; Star Forming Region; Stars, pre-main sequence
Keywords: Pre-main sequence stars ; Planetary atmospheres ; Protoplanetary
disks ; Stellar x-ray flares ; Single x-ray stars ; X-ray
stars
Abstract:
Measuring the evolution of X-ray emission from pre-main-sequence (PMS)
stars gives insight into two issues: the response of magnetic dynamo
processes to changes in the interior structure, and the effects of
high-energy radiation on protoplanetary disks and primordial planetary
atmospheres. We present a sample of 6003 stars with ages 7-25Myr in 10
nearby open clusters from Chandra X-ray and Gaia-EDR3 surveys.
Combined with previous results in large samples of younger (≲5Myr)
stars in MYStIX and SFiNCs star-forming regions, mass- stratified
activity-age relations are derived for the early phases of stellar
evolution. X-ray luminosity (LX) is constant during the first few Myr,
possibly due to the presence of extended X-ray coronas insensitive to
temporal changes in stellar size. LX then decays during the 7-25Myr
period, more rapidly as stellar mass increases. This decay is
interpreted as decreasing efficiency of the α2 dynamo as
radiative cores grow and a solar-type αΩ dynamo emerges.
For more massive 3.5-7M☉ fully radiative stars, the X-ray emission
plummets-indicating the lack of an effective magnetic dynamo. The
findings provide improved measurements of high-energy radiation
effects on circumstellar material, first for the protoplanetary disk
and then for the atmospheres of young planets. The observed X-ray
luminosities can be so high that an inner Earth-mass rocky,
unmagnetized planet around a solar-mass PMS star might lose its
primary and secondary atmospheres within a few (several) million
years. PMS X-ray emission may thus have a significant impact on the
evolution of early-planetary atmospheres and the conditions promoting
the rise of habitability.
Description:
All observations were performed using Chandra's Advanced CCD Imaging
Spectrometer imaging array (ACIS-I). Numerous 17x17' images from four
contiguous CCD chips were aimed at the centers of these clusters. All
but three observations were taken in Very Faint Timed Exposure mode;
ObsIDs 9912, 9913, and 12021 were taken in Faint mode.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 74 14222 X-ray Sources Towards 10 Open Clusters
table3.dat 98 10534 Gaia-EDR3 Properties Of Non-X-ray And X-ray Sources
Towards 10 Open Clusters
table4.dat 67 7924 Stellar Properties Of Non-X-ray And X-ray Members
Of 10 Open Clusters
table6.dat 93 40041 Stellar Properties of MYStIX and SFiNCs Members
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See also:
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
I/354 : StarHorse2, Gaia EDR3 photo-astrometric distances (Anders+, 2022)
J/ApJ/315/687 : X-Ray emission from solar-type stars F and G (Maggio+, 1987)
J/ApJ/574/258 : Xray-emitting young stars in Orion nebula (Feigelson+, 2002)
J/A+A/397/147 : Activity-rotation relationship in stars (Pizzolato+ 2003)
J/ApJS/160/319 : COUP; observations and source lists (Getman+, 2005)
J/A+A/468/353 : XMM-Newton Extended Survey of Taurus (Guedel+, 2007)
J/ApJ/708/1760 : Flux estimations of faint X-ray sources (Getman+, 2010)
J/ApJ/743/48 : Stars with rotation per & X-ray luminosities (Wright+, 2011)
J/A+A/539/A64 : X-ray data for IC 348 young stars (Alexander+, 2012)
J/ApJ/747/51 : Lagoon Nebula stars. I. Rotation periods (Henderson+, 2012)
J/ApJS/209/32 : Probable young stars in the MYStIX project (Broos+, 2013)
J/ApJS/209/27 : MYStIX; the Chandra X-ray sources (Kuhn+, 2013)
J/ApJ/787/109 : Age estimates for NGC 2024 and ONC stars (Getman+, 2014)
J/ApJ/787/108 : Age estimates massive SFR star populations (Getman+, 2014)
J/MNRAS/441/2361 : Stellar magnetism, age and rotation (Vidotto+, 2014)
J/ApJ/802/60 : Structure of young stellar clusters. II. (Kuhn+, 2015)
J/A+A/589/A113 : PMS stars in h Per (Argiroffi+, 2016)
J/ApJS/229/28 : SFiNCs; X-ray, IR and membership catalogs (Getman+, 2017)
J/A+A/605/A85 : NGC 3293 Chandra X-ray observation (Preibisch+, 2017)
J/A+A/620/A55 : Magnetic flaring from PMS stars spectra (Flaccomio+, 2018)
J/MNRAS/476/1213 : Ages for stars in 19 clusters (Getman+, 2018)
J/MNRAS/477/298 : Young star clusters nearby molecular clouds (Getman+, 2018)
J/AJ/156/271 : The stellar membership of the Taurus SFR (Luhman, 2018)
J/MNRAS/477/5191 : Galactic young stellar cluster lifetimes (Richert+, 2018)
J/MNRAS/487/2977 : Runaway stellar groups in the Orion A cloud (Getman+, 2019)
J/ApJ/870/32 : Kinematics young star clusters & associations (Kuhn+, 2019)
J/ApJS/244/28 : 3rd MSFRs Omnibus X-ray Catalog (MOXC3) (Townsley+, 2019)
J/A+A/633/A99 : Gaia DR2 open clusters Milky Way. II (Cantat-Gaudin+, 2020)
J/A+A/640/A1 : Portrait Galactic disc (Cantat-Gaudin+, 2020)
J/AJ/160/44 : Upper Scorpius spectroscopy and photometry (Luhman+, 2020)
J/A+A/648/A121 : X-ray activity and accretion in the ONC (Flaischlen+, 2021)
J/ApJ/916/32 : X-ray superflares PMS stars MYStIX & SFiNCs (Getman+, 2021)
J/A+A/649/A3 : Gaia EDR3 photometric passbands (Riello+, 2021)
J/A+A/661/A29 : First eROSITA study of nearby M dwarfs (Magaudda+, 2022)
J/AJ/163/68 : Fiducial stellar spectrum of HD 63433 (Zhang+, 2022)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Region Region
9- 26 A18 --- CXOU IAU Designation, CXOU JHHMMSS.ss±DDMMSS.s
28- 37 F10.6 deg RAdeg [34/194] Right Ascension (J2000)
39- 48 F10.6 deg DEdeg [-62/63] Declination, decimal degrees (J2000)
50- 55 F6.1 ct Cnet [0.1/2182] Net counts, (0.5-8)keV band
57- 60 F4.1 ct e_Cnet [1/48] Uncertainty (average of upper and
lower 1σ) on Cnet
62- 67 F6.3 ph/cm2/s PFlux [-7.645/-3.719] log, apparent photometric
flux, (0.5-8)keV band (1)
69- 71 F3.1 keV ME [0.5/7.7] Background-corrected median photon
energy, (0.5-8)keV band
73- 74 I2 --- Group [5/10] Source Class (2)
--------------------------------------------------------------------------------
Note (1): log of apparent photometric flux as the ratio of the net counts to
the mean Auxiliary Response File value (product of the local effective
area and quantum efficiency) and exposure time.
Note (2): Class as follows:
5 = Chandra-Gaia stars with their parallax confidence intervals intercepting
the PlxSpread band and their proper motion positions lying inside the
Rcl,pm circle, shown in panels a-d of Figure 2 and 3. Gaia photometry
indicates that the Group 5 objects are mainly cluster members with
masses > 0.5 Msun;
6 = Chandra-Gaia stars with their parallax confidence intervals intercepting
the PlxSpread band and their proper motion positions lying outside the
Rcl,pm circle, shown in panels a-d of Figure 2 and 3. Gaia photometry
indicates that the Group 6 objects include both < 2 Msun cluster members
and stellar contaminants;
7 = Chandra-Gaia stars with their lower error-bar on parallax being above
the PlxSpread band (Figure 2-3; panels d for Group 7). Group 7 is
predominantly foreground stars;
8 = Chandra-Gaia stars with their upper error-bar on parallax being below
the PlxSpread band (Figure 2-3; panels d for Group 8). Group 8 is
predominantly background stars;
9 = Group 9 comprises Chandra-Gaia sources without astrometry information.
Some may be very low-mass cluster members and some may be contaminants;
10 = Group 10 incorporates Chandra sources without Gaia counterparts.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Region Region
9- 18 F10.6 deg RAdeg [34/194] Right Ascension, Gaia EDR3,
decimal degrees (J2000 at Epoch=2000)
20- 29 F10.6 deg DEdeg [-62/63] Declination, Gaia EDR3,
decimal degrees (J2000 at Epoch=2000)
31- 31 I1 --- Group [1/8] Source Class (1)
33- 38 F6.3 mas plx [-8.83/9.28] Gaia EDR3 parallax
40- 44 F5.3 mas e_plx [0.009/3] Uncertainty in plx
46- 52 F7.3 mas/yr pmRA [-86.6/32.7] Proper motion in RA, Gaia EDR3
54- 58 F5.3 mas/yr e_pmRA [0.008/3] Uncertainty in pmRA
60- 66 F7.3 mas/yr pmDE [-32.2/29.1] Proper motion in DE, Gaia EDR3
68- 72 F5.3 mas/yr e_pmDE [0.009/3] Uncertainty in pmDE
74- 79 F6.3 mag Gmag [5.48/21.04]? Gaia EDR3 G-band magnitude
81- 85 F5.3 mag e_Gmag [0.003/0.058]? Uncertainty in Gmag
87- 92 F6.3 mag BP-RP [-0.684/4.627]? Gaia BP - RP color
94- 98 F5.3 mag e_BP-RP [0.005/5.564]? Uncertainty in BP-RP
--------------------------------------------------------------------------------
Note (1): Class as follows:
1 = non-Chandra Gaia sources with proper motion uncertainties of e_pm <
0.2 mas/yr and whose proper motion values lie inside the Rcl,pm circle
and their parallax confidence intervals intercept the PlxSpread band
(Figure 2-3; panels e-h). Group 1 stars are typically higher mass (> 1
? 2 Msun) cluster members;
2 = non-Chandra Gaia sources with proper motion uncertainties of 0.2 <
e_pm < 0.4 mas/yr and whose proper motion values lie inside the Rcl,pm
circle and their parallax confidence intervals intercept the PlxSpread
band (Figure 2-3; panels e-h). Many Group 2 stars are lower mass (< 1
M sun) cluster members;
3 = non-Chandra Gaia sources with proper motion uncertainties of e_pm >
0.4 mas/yr whose proper motion values lie inside the Rcl,pm circle and
their parallax confidence intervals intercept the PlxSpread band
(Figure 2-3; panels e-h). Group 3 stars include both low mass (< 0.5 ?
0.8 Msun) cluster member candidates and foreground and background
contaminants;
5 = Chandra-Gaia stars with their parallax confidence intervals intercepting
the PlxSpread band and their proper motion positions lying inside the
Rcl,pm circle, shown in panels a-d of Figure 2 and 3. Gaia photometry
indicates that the Group 5 objects are mainly cluster members with
masses > 0.5 Msun;
6 = Chandra-Gaia stars with their parallax confidence intervals intercepting
the PlxSpread band and their proper motion positions lying outside the
Rcl,pm circle, shown in panels a-d of Figure 2 and 3. Gaia photometry
indicates that the Group 6 objects include both < 2 Msun cluster members
and stellar contaminants;
7 = Chandra-Gaia stars with their lower error-bar on parallax being above
the PlxSpread band (Figure 2-3; panels d for Group 7). Group 7 is
predominantly foreground stars;
8 = Chandra-Gaia stars with their upper error-bar on parallax being below
the PlxSpread band (Figure 2-3; panels d for Group 8). Group 8 is
predominantly background stars;
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Region Region
9- 18 F10.6 deg RAdeg [34/194] Right Ascension, Gaia EDR3,
decimal degrees (J2000 at Epoch=2000)
20- 29 F10.6 deg DEdeg [-62/63] Declination, Gaia EDR3,
decimal degrees (J2000 at Epoch=2000)
31- 31 I1 --- Group [1/6] Source Class (1)
33- 36 F4.2 [K] logTeff [3.43/4.46] log, Stellar effective temperature
(2)
38- 42 F5.2 Msun Mstar [0.14/21.34] Stellar mass (2)
44- 48 F5.2 [Lsun] logLbol [-2.04/5.04] log, bolometric luminosity (2)
50- 54 F5.2 [10-7W] logLX [28.6/31.57]? Log, X-ray luminosity, erg/s
56- 60 F5.2 [10-7W] logLXup [28.46/31.06]? Log, upper limit X-ray
luminosity, erg/s
62- 62 I1 --- F1 [0/1] Cluster center flag (3)
64- 65 I2 --- Ph [1/14] HR diagram flag (4)
67- 67 I1 --- F2 [0/1] Gaia photometric consistency flag (5)
--------------------------------------------------------------------------------
Note (1): Source class as follows:
1 = non-Chandra Gaia sources with proper motion uncertainties of e_pm <
0.2 mas/yr and whose proper motion values lie inside the Rcl,pm circle
and their parallax confidence intervals intercept the PlxSpread band
(Figure 2-3; panels e-h). Group 1 stars are typically higher mass (> 1
? 2 Msun) cluster members;
2 = non-Chandra Gaia sources with proper motion uncertainties of 0.2 <
e_pm < 0.4 mas/yr and whose proper motion values lie inside the Rcl,pm
circle and their parallax confidence intervals intercept the PlxSpread
band (Figure 2-3; panels e-h). Many Group 2 stars are lower mass (< 1
M sun) cluster members;
5 = Chandra-Gaia stars with their parallax confidence intervals intercepting
the PlxSpread band and their proper motion positions lying inside the
Rcl,pm circle, shown in panels a-d of Figure 2 and 3. Gaia photometry
indicates that the Group 5 objects are mainly cluster members with
masses > 0.5 Msun;
6 = Chandra-Gaia stars with their parallax confidence intervals intercepting
the PlxSpread band and their proper motion positions lying outside the
Rcl,pm circle, shown in panels a-d of Figure 2 and 3. Gaia photometry
indicates that the Group 6 objects include both < 2 Msun cluster members
and stellar contaminants.
Note (2): Stellar effective temperature, mass, and bolometric luminosity
derived from the Gaia color-magnitude diagrams (Figure 4a,c).
Note (3): Flag indicating whether the star is located inside (= 0) or outside
(= 1) the spatial circle around the cluster center depicted in Figures 2i
and 3i.
Note (4): The evolutionary status of the star on the Hertzsprung?Russell
diagram based on the predictions of the PARSEC 1.2S evolutionary models:
1 = Hayashi track;
2 or 3 = Henyey track;
≥ 4 - ZAMS and beyond.
Note (5): Flag indicating sources with inconsistency (= 1) between the
Gaia G-band, and BP and RP photometry.
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Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Region Region
14- 32 A19 --- CXOU IAU Designation, CXOU JHHMMSS.ss±DDMMSS.s (1)
34- 43 F10.6 deg RAdeg [0/347] Right Ascension, decimal degrees (J2000)
45- 54 F10.6 deg DEdeg [-62/76] Declination, decimal degrees (J2000)
56- 58 F3.1 keV ME [0.5/7.5]? X-ray median energy, (0.5-8) keV band
60- 64 F5.1 mag AVmag [-24.3/71.2]? Visual extinction
66- 69 F4.1 Myr Age [0.1/16.2]? Stellar age (2)
71- 74 F4.2 [K] logTeff [3.41/4.78]? log, Stellar effective temperature
(3)
76- 80 F5.1 Msun Mstar [0.1/329.7]? Stellar mass (3)
82- 86 F5.2 [Lsun] logLbol [-1.78/6.93]? log, bolometric luminosity (3)
88- 91 F4.1 [10-7W] logLX [27.4/33.7]? log, X-ray luminosity, (0.5-8)keV
band, erg/s
93- 93 I1 --- Evol [1/5]? Evolutionary phase (4)
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Note (1): Source?s IAU designation. This identifier is used in the
MYStIX and SFiNCs member tables of Broos+, 2013, J/ApJ/209/32 and
Getman+, 2017, J/ApJS/229/28G.
Note (2): Stellar age estimated from the AgeJX chronometer,
Getman+, 2014, J/ApJ/787/108G.
Note (3): Stellar effective temperature, mass, and bolometric luminosity
derived from JHK color-magnitude diagrams,
Getman & Feigelson, 2021, J/ApJ/916/32.
Note (4): The evolutionary status of the star on the Hertzsprung?Russell
diagram based on PARSEC 1.2S model tracks (Figure 1) --
1 = Hayashi track;
2 or 3 = Henyey track;
≥4 = ZAMS.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 05-Jun-2024