Robo-AO Discovery and Basic Characterization of Wide Multiple Star Systems in the Pleiades, Praesepe, and NGC 2264 Clusters

Hillenbrand, Lynne A.; Zhang, Celia; Riddle, Reed; Baranec, Christoph; Ziegler, Carl; Law, Nicholas M.; Stauffer, J. R.

doi:10.3847/1538-3881/aaa01e

Cited by 13 publications

(11 citation statements)

References 68 publications

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“…To estimate our completeness we use the work of Hillenbrand et al (2018) as a comparison survey. This work searched for companions to Pleiades and Praesepe members using adaptive optics.…”

Section: Completenessmentioning

confidence: 99%

“…While most of their companions were at projected separations of less than an arcsecond and undetected by us, we recovered two of the four companions to stars that were in both our member selections and Hillenbrand et al ( 2018)'s sample which had separations of 1.0-1.5 arcseconds, two of the three with 1.5-2.0 arcsecond separations and all three of the companions wider than that. Some of the Hillenbrand et al (2018) targets did not appear in our sample as they fell outside our sky search area for each cluster, had no astrometric solution in Gaia or were not selected as members by our algorithm. For companions from Hillenbrand et al (2018) that are wider than two arcseconds we do not recover four Pleiades systems.…”

Section: Completenessmentioning

confidence: 99%

“…Some of the Hillenbrand et al (2018) targets did not appear in our sample as they fell outside our sky search area for each cluster, had no astrometric solution in Gaia or were not selected as members by our algorithm. For companions from Hillenbrand et al (2018) that are wider than two arcseconds we do not recover four Pleiades systems. Both components in all of these systems are excluded as Pleiades members due to their parallaxes with three (s5035799, HII 659 and s5197248) having proper motions that lie outside our cluster distribution.…”

Section: Completenessmentioning

confidence: 99%

“…We found that three of the objects (s5035799, HII 659 and s5197248) had proper motions that lay outside the proper motion distribution of Pleiades members found by Deacon & Hambly (2004) while obviously DH 800 was selected as a Pleiades member. This suggests that the absence of three wide Pleiades binaries from Hillenbrand et al (2018) is likely due to those binaries being field interlopers or objects in the kinematic outskirts of the cluster which we exclude from our Pleiades member sample rather than any bias we have against selecting wide binary components as cluster members. The additional proper motion information of Gaia only serves to further refine the input member list that was available to Hillenbrand et al (2018), it does not call the existence of any of their binaries into question.…”

Section: Completenessmentioning

confidence: 99%

“…Binary stars in clusters can be identified by their overluminosity (Stauffer 1984;Rubenstein & Bailyn 1997;Khalaj & Baumgardt 2013;Sheikhi et al 2016), lunar occultation (Richichi et al 2012), radial velocity techniques (Neill Reid & Mahoney 2000) or by direct imaging (Bouvier et al 1997;Patience et al 2002;Garcia et al 2015;Hillenbrand et al 2018). However these studies are typically limited to relatively close separations with only the direct imaging surveys going out to separations of a few hundred AU.…”

Section: Introductionmentioning

confidence: 99%

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Wide binaries are rare in open clusters

Deacon

Kraus

2020

Monthly Notices of the Royal Astronomical Society

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The population statistics of binary stars are an important output of star formation models. However, populations of wide binaries evolve over time due to interactions within a system’s birth environment and the unfolding of wide, hierarchical triple systems. Hence, the wide binary populations observed in star-forming regions or OB associations may not accurately reflect the wide binary populations that will eventually reach the field. We use Gaia DR2 data to select members of three open clusters, Alpha Per, the Pleiades, and Praesepe and to flag cluster members that are likely unresolved binaries due to overluminosity or elevated astrometric noise. We then identify the resolved wide binary population in each cluster, separating it from coincident pairings of unrelated cluster members. We find that these clusters have an average wide binary fraction in the 300–3000 au projected separation range of 2.1$\pm ^{0.4}_{0.2}$ per cent increasing to 3.0$\pm ^{0.8}_{0.7}$ per cent for primaries with masses in the 0.5–1.5 M⊙ range. This is significantly below the observed field wide binary fraction, but shows some wide binaries survive in these dynamically highly processed environments. We compare our results with another open cluster (the Hyades) and two populations of young stars that likely originated in looser associations (young moving groups and the Pisces-Eridanus stream). We find that the Hyades also has a deficit of wide binaries while the products of looser associations have wide binary fractions at or above field level.

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“…To estimate our completeness we use the work of Hillenbrand et al (2018) as a comparison survey. This work searched for companions to Pleiades and Praesepe members using adaptive optics.…”

Section: Completenessmentioning

confidence: 99%

Section: Completenessmentioning

confidence: 99%

Section: Completenessmentioning

confidence: 99%

Section: Completenessmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Wide binaries are rare in open clusters

Deacon

Kraus

2020

Monthly Notices of the Royal Astronomical Society

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The lithium-rotation connection in the 125 Myr-old Pleiades cluster

Bouvier

Barrado

Moraux

et al. 2018

A&A

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Context. The evolution of lithium abundance over a star's lifetime is indicative of transport processes operating in the stellar interior. Aims. We revisit the relationship between lithium content and rotation rate previously reported for cool dwarfs in the Pleiades cluster. Methods. We derive new LiI 670.8 nm equivalent width measurements from high-resolution spectra obtained for low-mass Pleiades members. We combine these new measurements with previously published ones, and use the Kepler/K2 rotational periods recently derived for Pleiades cool dwarfs to investigate the lithium-rotation connection in this 125 Myr-old cluster. Results. The new data confirm the correlation between lithium equivalent width and stellar spin rate for a sample of 51 early K-type members of the cluster, where fast rotating stars are systematically lithium-rich compared to slowly rotating ones. The correlation is valid for all stars over the (J-K s ) color range 0.50-0.70 mag, corresponding to a mass range from about 0.75 to 0.90 M , and may extend down to lower masses. Conclusions. We argue that the dispersion in lithium equivalent widths observed for cool dwarfs in the Pleiades cluster reflects an intrinsic scatter in lithium abundances, and suggest that the physical origin of the lithium dispersion pattern is to be found in the pre-main sequence rotational history of solar-type stars.

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A 5D view of the α Per, Pleiades, and Praesepe clusters

Lodieu

Garrido

Smart

et al. 2019

A&A

109

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Aims. Our scientific goal is to provide revised membership lists of the α Per, Pleiades, and Praesepe clusters exploiting the second data release of Gaia and produce five-dimensional maps (α, δ, π, µ α cosδ, µ δ ) of these clusters. Methods. We implemented the kinematic method combined with the statistical treatment of parallaxes and proper motions to identify astrometric member candidates of three of the most nearby and best studied open clusters in the sky. Results. We cross-correlated the Gaia catalogue with large-scale public surveys to complement the astrometry of Gaia with multiband photometry from the optical to the mid-infrared. We identified 517, 1248, and 721 bona-fide astrometric member candidates inside the tidal radius of the α Per, the Pleiades, and Praesepe, respectively. We cross-matched our final samples with catalogues from previous surveys to address the level of completeness. We update the main physical properties of the clusters, including mean distance and velocity as well as core, half-mass, and tidal radii. We infer updated ages from the white dwarf members of the Pleiades and Praesepe. We derive the luminosity and mass functions of the three clusters and compare them to the field mass function. We compute the positions in space of all member candidates in the three regions to investigate their distribution in space. Conclusions. We provide updated distances and kinematics for the three clusters. We identify a list of members in the α Per, Pleiades, and Praesepe clusters from the most massive stars all the way down into the hydrogen-burning limit with a higher confidence and better astrometry than previous studies. We produce complete 5D maps of stellar and substellar bona-fide members in these three regions. The photometric sequences derived in several colour-magnitude diagrams represent benchmark cluster sequences at ages from 90 to 600 Myr. We note the presence of a stream around the Pleiades cluster extending up to 40 pc from the cluster centre.

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Robo-AO Discovery and Basic Characterization of Wide Multiple Star Systems in the Pleiades, Praesepe, and NGC 2264 Clusters

Cited by 13 publications

References 68 publications

Wide binaries are rare in open clusters

Wide binaries are rare in open clusters

The lithium-rotation connection in the 125 Myr-old Pleiades cluster

A 5D view of the α Per, Pleiades, and Praesepe clusters

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