The Color-Period Diagram and Stellar Rotational Evolution—new Rotation Period Measurements in the Open Cluster M34

Meibom, S.; Mathieu, Robert D.; Stassun, Keivan G.; Liebesny, Paul; Saar, Steven H.

doi:10.1088/0004-637x/733/2/115

Cited by 153 publications

(126 citation statements)

References 78 publications

(108 reference statements)

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“…This study also revealed a strong correlation between the saturated and non-saturated regimes of X-ray emission and the C and I rotation sequences observed in M 34 (Irwin et al 2006;James et al 2010;Meibom et al 2011). Using the CgI sequence classification of M 35 stars by M09, a second set of X-ray luminosity distributions was calculated assuming that C-sequence and gap stars emit X-rays at the R X,sat saturation level and that I-sequence stars emit X-rays in the non-saturated regime.…”

Section: Discussionsupporting

confidence: 64%

“…In a recent paper, Gondoin (2012;hereafter G12) reported a correlation between the saturated and non-saturated regime of X-ray emission and the C A&A 556, A14 (2013) and I rotation sequences that have been observed in M 34 from extensive rotation periods surveys (Irwin et al 2006;James et al 2010;Meibom et al 2011). Messier 34 sample stars also show a steep transition in X-ray to bolometric luminosity ratio between the C-sequence and gap stars that emit close to the 10 −3 saturation level, and the I-sequence stars, whose L X /L bol ratio is significantly lower for similar values of the Rossby number.…”

Section: Introductionmentioning

confidence: 95%

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X-ray emission regimes and rotation sequences in M 35

Gondoin

2013

A&A

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Context. Late-type stars in young open clusters show two kinds of dependence of their X-ray emission on rotation. They also tend to group into two main sub-populations that lie on narrow sequences in diagrams where their rotation periods are plotted against their (B − V) colour indices. A correlation between these two regimes of X-ray emission and the rotation sequences has been recently observed in the M 34 open cluster. Sun-like M 34 stars also show a drop of their X-ray to bolometric luminosity ratio by about one order of magnitude at a Rossby number of about 0.3. Aims. The present study looks for similar connections between X-ray activity and rotation in an other open cluster. The aim is to consolidate a model of X-ray activity evolution on the main sequence and to provide observational constraints on dynamo processes in the interiors of late-type stars. Methods. The paper compares XMM-Newton measurements of X-ray stellar emission in M 35 with X-ray luminosity distributions derived from rotation period measurements assuming either an X-ray regime transition at a critical Rossby number or a correlation between X-ray emission regimes and rotation sequences. Results. This second hypothesis could account for the low number of M 35 stars detected in X-rays. A model of X-ray activity evolution is proposed based on the correlation. One major output is that the transition from saturated to non-saturated X-ray emission occurs at Rossby numbers between about 0.13 and 0.4 for each star depending on its mass and initial period of rotation on the ZAMS. This prediction agrees with observations of stellar X-ray emission in M 34. It explains the large range of X-ray luminosities observed among Sun-like stars in young open clusters. Conclusions. I conclude that the correlation between X-ray emission regimes and rotation sequences could be a fundamental property of the early evolution of stellar magnetic activity on the main sequence. I argue that the angular momentum redistribution mechanism(s) responsible for the transition between rotation sequences could result in a changing mixture of dynamo processes occurring side by side, possibly including a turbulent dynamo at high rotation rate and an interface-type dynamo whose efficiency decreases progressively at later stage of stellar evolution when rotation dies away.

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Section: Discussionsupporting

confidence: 64%

Section: Introductionmentioning

confidence: 95%

X-ray emission regimes and rotation sequences in M 35

Gondoin

2013

A&A

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“…Detection was made of 189 X-ray sources that are listed in the XMM − Newton Serendipitous Source Catalog (Watson et al 2009). This list of X-ray sources was correlated with lists of M34 cluster members with known rotation periods established by Meibom et al (2011), Irwin et al (2006), and James et al (2010). In total, 41 single stars in the M34 open cluster have been found that have known rotational periods and detected X-ray emissions (Gondoin 2012).…”

Section: X-ray Observations Of the M34 Open Clustermentioning

confidence: 98%

“…Figure 1 (left) shows the rotational periods P of the sample stars as a function of their reddening corrected (B − V) 0 indices. The color-period diagram also displays the I and C rotational sequences of M34 along the form established by Barnes (2007) and Meibom et al (2011). The proximity of the M34 data points to these curves was used to determine their membership to the I sequence, to the C sequence or to the gap.…”

Section: X-ray Observations Of the M34 Open Clustermentioning

confidence: 99%

X-ray emission regimes and rotation sequences in the M34 open cluster

Gondoin¹

2013

Proc. IAU

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Abstract. I report on a correlation between the saturated and non-saturated regimes of Xray emission and the rotation sequences that have been observed in the M34 open cluster. An interpretation of this correlation in term of magnetic activity evolution in the early stage of evolution on the main sequence is presented. X-ray fluxes were derived from the source count rates using energy conversion factors (ECF) calculated in the 0.5-4.5 keV range (Gondoin 2006). The X-ray fluxes were converted into stellar X-ray luminosities assuming a distance of 470 pc (Jones & Prosser 1996). The X-ray luminosity distribution of the sample stars rolls off at luminosities lower than L X ≈ 10 29 erg s −1 , which provides a sensitivity limit estimate of the XMM − Newton observation. The mass of the sample stars ranges from 0.4 M to 1.3 M and reaches a maximum around 0.8 M . Their rotation periods are between 0.49 days and 11 days. X-ray observations of the M34 open clusterRecent studies have shown that stars tend to group into two main sub-populations that lie on narrow sequences in diagrams where the measured rotation periods of the members of a young stellar cluster are plotted against their B − V colors. Figure 1 (left) shows the rotational periods P of the sample stars as a function of their reddening corrected (B − V) 0 indices. The color-period diagram also displays the I and C rotational sequences of M34 along the form established by Barnes (2007) and Meibom et al. (2011). The proximity of the M34 data points to these curves was used to determine their membership to the I sequence, to the C sequence or to the gap. Figure 1 (right) displays the X-ray to bolometric luminosity ratio L X /L bol of the sample stars as a function of their Rossby number (Ro = P /τ c ) distinguishing members of the I sequence, of the C sequence and of the gap. Figure 1 shows a correlation between the X-ray activity regimes and the rotation sequences. Indeed, members of the C sequence have small Rossby numbers (Ro < 0.1), and an X-ray to bolometric luminosity level close to the 10 −3 saturation level. Members of the I sequence, in contrast, have larger Rossby numbers (Ro 0.17), and an X-ray to bolometric luminosity ratio significantly smaller than the saturation limit. Remarkably, 106at https://www.cambridge.org/core/terms. https://doi

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“…Among these properties are a cluster's turn-off age and average metallicity and also the lithium abundance and dispersion of its G dwarfs in order to relate eventual models to the Sun as a star. While space-based photometry is clearly superior for periodicities of various sorts, ground-based multi-band photometry and follow-up spectroscopy are essential in determining membership, abundances, and binarity (see, e.g., Meibom et al 2011;Milliman et al 2014). We have therefore used the A&A 580, A66 (2015) Herzog et al (1975) CoRoT satellite (Baglin et al 2006) in its sixth long run to observe selected and bona fide member stars of the open cluster IC 4756 that happened to be within the exoplanet field of view of the satellite.…”

Section: Introductionmentioning

confidence: 99%

Stellar rotation, binarity, and lithium in the open cluster IC 4756

Strassmeier

Weingrill

Granzer

et al. 2015

A&A

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Context. An important aspect in the evolutionary scenario of cool stars is their rotation and the rotationally induced magnetic activity and interior mixing. Stars in open clusters are particularly useful tracers for these aspects because of their known ages. Aims. We aim to characterize the open cluster IC 4756 and measure stellar rotation periods and surface differential rotation for a sample of its member stars. Methods. Thirty-seven cluster stars were observed continuously with the CoRoT satellite for 78 days in 2010. Follow-up highresolution spectroscopy of the CoRoT targets and deep Strömgren uvbyβ and Hα photometry of the entire cluster were obtained with our robotic STELLA facility and its echelle spectrograph and wide-field imager, respectively. Results. We determined high-precision photometric periods for 27 of the 37 CoRoT targets and found values between 0.155 and 11.4 days. Twenty of these are rotation periods. Twelve targets are spectroscopic binaries of which 11 were previously unknown; orbits are given for six of them. Six targets were found that show evidence of differential rotation with ΔΩ/Ω in the range 0.04−0.15. Five stars are non-radially pulsating stars with fundamental periods of below 1 d, two stars are semi-contact binaries, and one target is a micro-flaring star that also shows rotational modulation. Nine stars in total were not considered members because of much redder color(s) and deviant radial velocities with respect to the cluster mean. Hα photometry indicates that the cluster ensemble does not contain magnetically over-active stars. The cluster average metallicity is -0.08 ± 0.06 (rms) and its logarithmic lithium abundance for 12 G-dwarf stars is 2.39 ± 0.17 (rms). Conclusions. The cluster is 890 ± 70 Myrs old with an average turn-off mass of 1.8 M and a solar or slightly subsolar metallicity. The distance modulus is 8. m 02 and the average reddening E(b − y) = 0. m 16. The cluster is masked by a very inhomogeneous foreground and background dust distribution and our survey covered 38% of the cluster. The average lithium abundance and the rotation periods in the range 1.7 to 11.4 d are consistent with the cluster age.

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The Color-Period Diagram and Stellar Rotational Evolution—new Rotation Period Measurements in the Open Cluster M34

Cited by 153 publications

References 78 publications

X-ray emission regimes and rotation sequences in M 35

X-ray emission regimes and rotation sequences in M 35

X-ray emission regimes and rotation sequences in the M34 open cluster

Stellar rotation, binarity, and lithium in the open cluster IC 4756

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