J/A+A/652/A60 Rotation periods for NGC 3532 (Fritzewski+, 2021)
Rotation periods for cool stars in the open cluster NGC 3532.
The transition from fast to slow rotation.
Fritzewski D.J., Barnes S.A., James D.J., Strassmeier K.G.
<Astron. Astrophys. 652, A60 (2021)>
=2021A&A...652A..60F 2021A&A...652A..60F (SIMBAD/NED BibCode)
ADC_Keywords: Stars, late-type; Stars, variable; Photometry; Clusters, open
Keywords: stars: rotation - stars: solar-type - starspots -
stars: variables: general -
open clusters and associations: individual: NGC 3532 -
techniques: photometric
Abstract:
A very rich cluster intermediate in age between the Pleiades (150Myr)
and the Hyades (600Myr) is needed to probe the rotational evolution,
especially the transition between fast and slow rotation that occurs
between the two ages.
We study the rich 300Myr-old open cluster NGC 3532 to probe this
important transition and to provide constraints on angular momentum
loss. Measuring the rotation periods builds on our prior work of
providing spectroscopic membership information for the cluster, and it
supports the chromospheric activity measurements of cluster stars that
we provide in a companion paper.
Using 42d-long photometric time series observations obtained with the
Yale 1m telescope at CTIO, we measured rotation periods for members of
NGC 3532 and compared them with the predictions of angular momentum
evolution models.
We directly measured 176 photometric rotation periods for the cluster
members.
An additional 113 photometric rotation periods were identified using
activity information, described fully in the companion paper,
resulting in a total sample containing 279 rotation periods for FGKM
stars in NGC 3532. The colour-period diagram constructed from this
rich data set shows a well-populated and structured slow rotator
sequence, and a fast rotator sequence evolved beyond zero-age main
sequence age whose stars are in transition from fast to slow rotation.
The slow rotator sequence itself is split into slightly slower and
faster rotators, a feature we trace to photometric binary status. We
also identify an extended slow rotator sequence extending to P∼32d,
apparently the analogue of the one we previously identified in NGC
2516. We compare our period distribution to rotational isochrones in
colour-period space and find that all considered models have certain
shortcomings. Using more detailed spin-down models, we evolve the
rotation periods of the younger NGC 2516 forward in time and find that
the spindown of the models is too aggressive with respect to the slow
rotators. In contrast, stars on the evolved fast rotator sequence are
not spun down strongly enough by these models. Our observations
suggest a shorter crossing time for the rotational gap, one we
estimate to be ∼80Myr for early-K dwarfs.
Description:
The table contains the rotation periods and photometric colours for
279 solar-like members of the open cluster NGC 3532. Each star is
cross-matched to Gaia DR2. The possible binarity status (from
photometry and astrometry) is given.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 121 279 Rotation periods and photometric colours for 279
solar-like members of the open cluster NGC 3532
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/AJ/141/115 : BV(RI)c photometry on NGC 3532 (Clem+ 2011)
J/A+A/622/A110 : Spectroscopic membership for NGC 3532 (Fritzewski+ 2019)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 20 A20 --- ID ID(s) from Fritzewski et al.
(2019A&A...622A.110F 2019A&A...622A.110F, Cat. J/A+A/622/A110)
22- 29 A8 --- --- [Gaia DR2]
31- 49 I19 --- GaiaDR2 Gaia DR2 designation
51- 56 I6 --- CLHW ID from Clem et al. (2011AJ....141..115C 2011AJ....141..115C,
Cat. J/AJ/141/115)
58- 66 F9.5 deg RAdeg Right ascension from Gaia DR2 (ICRS) at
Ep=2015.5 (Cat. I/345)
68- 76 F9.5 deg DEdeg Declination from Gaia DR2 (ICRS) at Ep=2015.5
78- 82 F5.3 mag (B-V)0 (B-V)_0 colour from Clem et al.
(2011AJ....141..115C 2011AJ....141..115C, Cat. J/AJ/141/115) (1)
84- 89 F6.3 mag Vmag V magnitude from Clem+ (2011AJ....141..115C 2011AJ....141..115C,
Cat. J/AJ/141/115)
91- 95 F5.3 mag (V-Ks)0 ? (V-Ks)_0 colour based on Vmag and
2MASS Ks (1)
97-103 F7.4 d Prot Rotation period
105-110 F6.4 d e_Prot uncertainty in rotation period
112-117 F6.4 mag P90 Variability amplitude
119 I1 --- Class [0/3] Classification of period (2)
121 I1 --- Binary [0/1] Binary status (1 for true)
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Note (1): Dereddened with E(B-V)=0.034, E(V-Ks)=0.095
(Fritzewski et al., 2019A&A...622A.110F 2019A&A...622A.110F, Cat. J/A+A/622/A110).
Note (2): Classes as follows:
0 = possible alias
1 = first class
2 = algorithmic periods
3 = activity-informed periods
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Acknowledgements:
Dario Fritzewski, dfritzewski(at)aip.de
(End) Patricia Vannier [CDS] 01-Jun-2021