J/ApJ/952/63 Gaia-Chandra members of 7-25Myr clusters with ZTF (Getman+, 2023)
Magnetic activity-rotation-age-mass relations in late-pre-main-sequence stars.
Getman K.V., Feigelson E.D., Garmire G.P.
<Astrophys. J., 952, 63 (2023)>
=2023ApJ...952...63G 2023ApJ...952...63G
ADC_Keywords: Stars, G-type; Stars, pre-main sequence; Photometry; Optical;
X-ray sources; Stars, masses; Stars, ages; Effective temperatures
Keywords: Pre-main sequence stars ; Stellar rotation ; Single x-ray stars ;
X-ray stars ; Protoplanetary disks ; Stellar magnetic fields
Abstract:
We study the four-dimensional relationships between magnetic activity,
rotation, mass, and age for solar-type stars in the age range 5-25Myr.
This is the late-pre-main-sequence (l-PMS) evolutionary phase when
rapid changes in a star's interior may lead to changes in the magnetic
dynamo mechanisms. We carefully derive rotational periods and spot
sizes for 471 members of several l-PMS open clusters using photometric
light curves from the Zwicky Transient Facility. Magnetic activity was
measured in our previous Chandra-based study, and additional
rotational data were obtained from other work. Several results emerge.
Mass-dependent evolution of rotation through the l-PMS phase agrees
with astrophysical models of stellar angular momentum changes,
although the data suggest a subpopulation of stars with slower initial
rotations than commonly assumed. There is a hint of the onset of
unsaturated tachoclinal dependency of X-ray activity on rotation, as
reported by Argiroffi+ (2016, J/A+A/589/A113), but this result is not
confidently confirmed. Both X-ray luminosity and starspot area
decrease approximately as t-1 for solar-mass stars, suggesting that
spot magnetic fields are roughly constant and l-PMS stars follow the
universal solar-scaling law between the X-ray luminosity and surface
magnetic flux. Assuming convective dynamos are dominant, theoretical
magnetic fluxes fail to reveal the universal law for l-PMS stars that
enter late Henyey tracks. Altogether we emerge with a few lines of
evidence suggesting that the transition from the turbulent to
solar-type dynamo occurs at the later stages of l-PMS evolution as
stars approach the zero-age main sequence.
Description:
We investigate activity-rotation-age-mass relations for the
Gaia-Chandra stellar members of the six 7-25Myr old clusters studied
in Paper I (Getman+ 2022, J/ApJ/935/43) that are accessible to the
Palomar 60 inch telescope used for the ZTF survey. These include the
7Myr old NGC 1502 (256 members from Table 4 in Paper I), 7Myr old
NGC2169 (104 members), 13Myr old NGC 869 (1370 members), and NGC 884
(1294 members) commonly known as h and χ Persei, 22Myr old NGC1960
(406 members), and 25Myr old NGC 2232 (117 members). Out of
3547 members of these clusters, 3410 have ZTF light curves with at
least 100 photometric observations that we examine in this study.
The Chandra X-ray and Gaia Early Data Release 3 (EDR3) data giving
cluster memberships are discussed in Paper I.
Table 1 here gives stellar properties and X-ray luminosities for a
subset of 471 stars from Paper I for which we obtain reliable
rotational periods from ZTF light curves (see Section 3). We then add
95 stellar members of the 5Myr old NGC 2362 open cluster for which
stellar rotational periods are obtained by Irwin+ (2008, J/MNRAS/384/675).
We extend our X-ray-rotation data sample (Section 2.1, Table 1) by
adding other stars in the 5-25Myr age range (mostly without Chandra
data) with previously reported rotation periods. These additional
stars include members of the NGC 2362 and NGC 869 (including many
members outside Chandra fields), Upper Sco (US), Upper Centaurus-Lupus
(UCL), and Lower Centaurus-Crux (LCC) subregions of the Sco-Cen
Association, and the Pleiades. See Section 2.2 and Table 3.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
t1pap1.dat 79 15 The 10 late-PMS open clusters from Paper I
(Getman+ 2022, J/ApJ/935/43) and the additional
clusters; table added by CDS
table1.dat 79 566 5-25Myr PMS stars with rotation and X-ray properties
table3.dat 84 3879 *Gaia-DR3 masses for stars with previously published
rotation periods
table4.dat 35 7924 New HRD statuses for l-PMS stars from Paper I
(Getman+ 2022, J/ApJ/935/43)
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Note on table3.dat: Only stars with e_B-R<0.1mag are included in this table
and corresponding Figure 11.
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-2014)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
J/ApJ/315/687 : X-Ray emission from solar-type stars: F & G (Maggio+, 1987)
J/A+A/397/147 : Activity-rotation relationship in stars (Pizzolato+ 2003)
J/MNRAS/384/675 : Monitoring low-mass stars in NGC 2362 (Irwin+ 2008)
J/MNRAS/383/1588 : VIc photometry of NGC 2547 low-mass stars (Irwin+, 2008)
J/ApJ/708/1760 : Flux estimations of faint X-ray sources (Getman+, 2010)
J/ApJ/743/48 : Stars with rot. periods & 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/MNRAS/430/1433 : NGC 2264 members periods with CoRoT (Affer+, 2013)
J/ApJS/209/32 : Probable young stars in the MYStIX project (Broos+, 2013)
J/A+A/560/A13 : Stellar rotation in h Per (Moraux+, 2013)
J/A+A/549/A18 : WASP-30 and J1219-39 light & velocity curves (Triaud+, 2013)
J/ApJ/787/108 : Age estimates for massive SFR stellar pop. (Getman+, 2014)
J/ApJS/211/24 : Rotation periods of Kepler MS stars (McQuillan+, 2014)
J/MNRAS/441/2361 : Stellar magnetism, age and rotation (Vidotto+, 2014)
J/A+A/589/A113 : PMS stars in h Per (Argiroffi+, 2016)
J/AJ/152/113 : Pleiades members with K2 LCs. I. Periods (Rebull+, 2016)
J/ApJS/229/28 : SFiNCs: X-ray, IR and membership catalogs (Getman+, 2017)
J/A+A/599/A49 : PMS stars evolutionary models (Kunitomo+, 2017)
J/AJ/155/196 : K2 LCs for members of USco & ρ Oph (Rebull+, 2018)
J/MNRAS/477/5191 : Galactic young stellar cluster lifetimes (Richert+, 2018)
J/A+A/631/A77 : Low-mass stellar models and isochrones (Amard+, 2019)
J/AJ/158/58 : Autoregressive planet search with Kepler (Caceres+, 2019)
J/MNRAS/487/2977 : Runaway stellar groups in the Orion A cloud (Getman+, 2019)
J/ApJ/870/32 : Kinematics in young star clusters & assoc. (Kuhn+, 2019)
J/AJ/160/44 : Upper Scorpius spectroscopy and photometry (Luhman+, 2020)
J/ApJ/893/67 : Smoothed amplitudes from Kepler, K2 and TESS (Morris, 2020)
J/AJ/159/273 : Taurus members & nonmembers with K2 data (Rebull+, 2020)
J/ApJ/916/32 : X-ray superflares from MYStIX & SFiNCs (Getman+, 2021)
J/ApJ/907/89 : Starspots's temp. and area in 337 KIC stars (Herbst+, 2021)
J/MNRAS/513/420 : NGTS Variability Study (Briegal+, 2022)
J/ApJ/935/43 : X-ray Sources Towards 10 Open Clusters (Getman+, 2022)
J/AJ/164/137 : Untangling the Galaxy. IV. TESS (Kounkel+, 2022)
J/AJ/164/251 : ZTF measured rot. period of 40553 M- or G-dwarfs (Lu+, 2022)
J/A+A/663/A142 : GAPS programme at TNG. XXXIV. (Maldonado+, 2022)
J/AJ/164/80 : Periods for UCL/LCC non/members (Rebull+, 2022)
J/A+A/662/A41 : Magnetic fields in 292 M dwarfs. (Reiners+, 2022)
J/MNRAS/519/5304 : Rossby numbers of convective stars (Landin+, 2023)
Byte-by-byte Description of file: t1pap1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Cluster Cluster identifier
10- 30 A21 --- OName Other cluster identifier
32 A1 --- f_Cluster [ia] Flag on Cluster (1)
34- 41 F8.4 deg GLON [134.6/351.5] Galactic longitude for the
cluster center
43- 50 F8.4 deg GLAT [-23.6/20] Galactic latitude for the cluster
center
52- 55 I4 --- Nm [104/1968]? Total number of cluster members
identified across entire Chandra fields
57- 60 I4 --- Nmcent [90/1291]? Stellar members located in the
central parts of the clusters
62- 65 I4 pc Dist [319/2552]? Median cluster distance from the Sun
67- 68 I2 pc e_Dist [1/34]? 68% bootstrap error on Dist
70- 72 F3.1 mag Av [0.2/2.1]? Cluster average extinction in visual
band
74- 75 I2 Myr Age [7/25]? Cluster age
77- 79 F3.1 Msun Mlim [0.4/1]? Mass completeness limits for our
cluster member samples
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Note (1): Flag on Cluster as follows:
i = NGC 2362 cluster, with rotation periods taken
from Irwin+ 2008, J/MNRAS/384/675
a = Additional cluster for late-PMS stars without X-ray measurements;
see Section 2.2 (and Table 3).
Coordinates for those clusters are taken from SIMBAD.
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Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/566] Sequential source number
5- 11 A7 --- Cluster Cluster identifier
13- 22 F10.6 deg RAdeg [34.4/110] Gaia DR3 Right Ascension (J2000)
24- 33 F10.6 deg DEdeg [-25.1/62.6] Gaia DR3 Declination (J2000)
35- 38 F4.2 [K] logTeff [3.48/4.3] Log effective temperature (1)
40- 43 F4.2 Msun Mass [0.27/6.5] Mass (1)
45- 49 F5.2 [Lsun] logLbol [-1.5/3.2] Log bolometric luminosity (1)
51- 55 F5.2 d PRot [0.2/32.51] Rotation period (2)
57- 61 F5.3 mag Amp [0.002/0.4] Peak-to-peak photometric
amplitude (3)
63- 67 F5.2 [10-7W] logLx [28.7/31.5]? Log Chandra 0.5-8keV X-ray
luminosity; erg/s
69- 73 F5.2 [10-7W] logLxup [28.47/30.4]? Upper log Chandra 0.5-8keV
X-ray luminosity limit; erg/s
75- 79 F5.1 d tau [6.2/403.7]? Convective turnover timescale (4)
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Note (1): Derived from the Gaia color-magnitude diagrams. For the stars 1-471,
these quantities are from Table 4 of Paper I
(Getman+ 2022, J/ApJ/935/43).
For the NGC 2362 members, these quantities are re-derived in the
current paper.
Note (2): For the stars 1-471, these are derived here from ZTF lightcurves;
values for NGC 2362 are taken from Irwin+ 2008, J/MNRAS/384/675
(<[IHA2008b] N2362-N-NNNNN> in Simbad)
Note (3): Of the spot rotational modulation from folded lightcurves.
Note (4): Integrated over the convective envelope based on the stellar mass,
age and rotation using models of Amard+ 2019A&A...631A..77A 2019A&A...631A..77A
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Cluster Cluster identifier
10- 19 F10.6 deg RAdeg [34.48/259] Gaia DR3 Right Ascension (J2000)
21- 30 F10.6 deg DEdeg [-72.7/57.3] Gaia DR3 Declination (J2000)
32- 37 F6.3 mag Gmag [5.8/20.1] Gaia DR3 G band magnitude
39- 43 F5.3 mag e_Gmag [0.003/0.03] Uncertainty in Gmag
45- 50 F6.3 mag B-R [-0.05/4.8] Gaia DR3 (Blue-Red) passband color
52- 56 F5.3 mag e_B-R [0.005/0.1] Uncertainty in B-R
58- 61 F4.2 [K] logTeff [3.4/4.24] Log effective temperature (1)
63- 66 F4.2 Msun Mass [0.06/5] Mass (1)
68- 72 F5.2 [Lsun] logLbol [-2.54/2.8] Log Bolometric luminosity (1)
74- 78 F5.2 d PRot [0.04/27.1] Rotation period (2)
80- 84 F5.3 mag Amp [0.002/0.6]? Peak-to-peak photometric
amplitude (3)
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Note (1): Estimated in this paper and derived from the Gaia
color-magnitude diagrams.
Note (2): Rotation periods are from:
NGC 2362 = Irwin et al. 2008, J/MNRAS/384/675
Upper Sco = Rebull et al. 2018, J/AJ/155/196
NGC 869 = Moraux et al. 2013, J/A+A/560/A13
UCL & LCC = Rebull et al. 2022, J/AJ/164/80
Pleiades = Rebull et al. 2016, J/AJ/152/113
For NGC 2362 and NGC 869, there is overlap between the current sample
and the X-ray-rotation sample given in Table 1.
Note (3): The amplitudes are only available for NGC 2362 and NGC 869.
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Cluster Cluster identifier
9- 18 F10.6 deg RAdeg [34.4/194] Gaia DR3 Right Ascension (J2000)
20- 29 F10.6 deg DEdeg [-61.8/62.6] Gaia DR3 Declination (J2000)
31- 35 F5.2 --- phHRD [1/13.54] Updated stellar evolutionary phase (1)
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Note (1): The l-PMS cluster distributions are compared to the well-studied
Pleiades ZAMS-MS stars. At a given cluster age, the mass strata
distinguish between stars of different evolutionary phases, such as
Hayashi versus Henyey tracks at 7Myr, 13Myr, and >20Myr. These
evolutionary phases, called phHRD here, are taken from the PARSEC 1.2S
mass tracks by Chen+ (2014MNRAS.444.2525C 2014MNRAS.444.2525C). See Section 4.
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History:
From electronic version of the journal
References:
Getman et al. Paper I. 2022ApJ...935...43G 2022ApJ...935...43G Cat. J/ApJ/935/43
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 27-Aug-2025