Lunar occultations of Praesepe. II - Massachusetts

Peterson, D. M.; Baron, R. L.; Dunham, E. W.; Mink, Jessica; Aldering, G.; Klavetter, J. J.; Morgan, R.

doi:10.1086/115285

Cited by 6 publications

(11 citation statements)

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“…Surveys for multiple systems in Praesepe have been undertaken using lunar occulations (Peterson & White 1984;Peterson et al 1989), spectroscopy (Mermilliod et al 1990;Bolte 1991;Abt & Willmarth 1999;Mermilliod & Mayor 1999;Halbwachs et al 2003), speckle imaging (Mason et al 1993;Patience et al 2002), adaptive optics imaging (Bouvier et al 2001), and time-domain photometry (e.g., Pepper et al 2008). Spectroscopic binaries in Praesepe have also been identified through larger radial velocity (RV) surveys (Pourbaix et al 2004;Mermilliod et al 2009).…”

Section: Literature Identificationsmentioning

confidence: 99%

Poking the Beehive from Space: K2 Rotation Periods for Praesepe

Douglas

Agüeros

Covey

et al. 2017

ApJ

126

164

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We analyze K2 light curves for 794 low-mass (1 > ∼ M * > ∼ 0.1 M ⊙ ) members of the ≈650-Myr-old open cluster Praesepe, and measure rotation periods (P rot ) for 677 of these stars. We find that half of the rapidly rotating > ∼ 0.3 M ⊙ stars are confirmed or candidate binary systems. The remaining > ∼ 0.3 M ⊙ fast rotators have not been searched for companions, and are therefore not confirmed single stars. We found previously that nearly all rapidly rotating > ∼ 0.3 M ⊙ stars in the Hyades are binaries, but we require deeper binary searches in Praesepe to confirm whether binaries in these two co-eval clusters have different P rot distributions. We also compare the observed P rot distribution in Praesepe to that predicted by models of angular-momentum evolution. We do not observe the clear bimodal P rot distribution predicted by Brown (2014) for >0.5 M ⊙ stars at the age of Praesepe, but 0.25−0.5 M ⊙ stars do show stronger bimodality. In addition, we find that >60% of early M dwarfs in Praesepe rotate more slowly than predicted at 650 Myr by Matt et al. (2015), which suggests an increase in braking efficiency for these stars relative to solar-type stars and fully convective stars. The incompleteness of surveys for binaries in open clusters likely impacts our comparison with these models, since the models only attempt to describe the evolution of isolated single stars.

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Section: Literature Identificationsmentioning

confidence: 99%

Poking the Beehive from Space: K2 Rotation Periods for Praesepe

Douglas

Agüeros

Covey

et al. 2017

ApJ

126

164

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“…Needless to say, the CMD position does not adequately represent any of the component stars, and all are likely to be near the main sequence. Speckle interferometry (Mason et al 1993a;McAlister et al 1989;Hartkopf et al 1994Hartkopf et al , 1997Hartkopf et al , 2000Tokovinin 2017) and lunar occultation (Peterson et al 1989) probably show orbital motion of the third star, approximately 1.6 mag fainter with about 0. 1 angular separation.…”

Section: Discussionmentioning

confidence: 96%

“…Breger et al (2012) finds light variations with full amplitude of about 0.06 mag. No companion was detected during lunar occultations (Peterson & White 1984;Peterson et al 1989) or speckle interferometry (Mason et al 1993a). HD 73210 / KW 50: Abt & Willmarth (1999) derive a double-line spectroscopic orbit with a 12 day period for this star.…”

Section: Discussionmentioning

confidence: 98%

“…Although lunar occultations of Cnc have been observed several times (Peterson & White 1984;Peterson et al 1989), the system was not previously resolved. As we will see from the modeling below, this is largely due to a confluence of aggravating factors: a high inclination, an orientation of the orbit that strongly foreshortens the major axis, and a mostly north-south alignment of the minor axis (putting it fairly close to perpendicular to the ecliptic).…”

Section: Interferometrymentioning

confidence: 99%

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The Interferometric Binary Epsilon Cancri in Praesepe: Precise Masses and Age

Morales,

Sandquist,

Schaefer

et al. 2022

Preprint

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We observe the brightest member of the Praesepe cluster, Cnc, to precisely measure the characteristics of the stars in this binary system, en route to a new measurement of the cluster's age. We present spectroscopic radial velocity measurements and interferometric observations of the sky-projected orbit to derive the masses, which we find to be M 1 /M = 2.420 ± 0.008 and M 2 /M = 2.226 ± 0.004. We place limits on the color-magnitude positions of the stars by using spectroscopic and interferometric luminosity ratios while trying to reproduce the spectral energy distribution of Cnc. We re-examine the cluster membership of stars at the bright end of the color-magnitude diagram using Gaia data and literature radial velocity information. The binary star data are consistent with an age of 637 ± 19 Myr, as determined from MIST model isochrones. The masses and luminosities of the stars appear to select models with the most commonly used amount of convective core overshooting.

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“…Patience et al (2002) surveyed B through M stars and found a smaller binary fraction over the same separation range, but also had a smaller sample. Peterson et al (1984Peterson et al ( , 1989 identified several new Praesepe binaries from lunar occulation observations. In NGC 2264, there have been few dedicated binary studies.…”

Section: Introductionmentioning

confidence: 99%

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

Hillenbrand

Zhang

Riddle

et al. 2018

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We identify and roughly characterize 66 candidate binary star systems in the Pleiades, Praesepe, and NGC 2264 star clusters, based on robotic adaptive optics imaging data obtained using Robo-AO at the Palomar 60″ telescope. Only ∼10% of our imaged pairs were previously known. We detect companions at red optical wavelengths, with physical separations ranging from a few tens to a few thousands of au. A three-sigma contrast curve generated for each final image provides upper limits to the brightness ratios for any undetected putative companions. The observations are sensitive to companions with a maximum contrast of ∼6 m at larger separations. At smaller separations, the mean (best) raw contrast at 2″ is 3 8 (6 m ), at 1″ is 3 0 (4 5), and at 0 5 is 1 9 (3 m ). Pointspread function subtraction can recover nearly the full contrast in the closer separations. For detected candidate binary pairs, we report separations, position angles, and relative magnitudes. Theoretical isochrones appropriate to the Pleiades and Praesepe clusters are then used to determine the corresponding binary mass ratios, which range from 0.2 to 0.9 in = q m m 2 1 . For our sample of roughly solar-mass (FGK type) stars in NGC 2264 and sub-solarmass (K and early M-type) primaries in the Pleiades and Praesepe, the overall binary frequency is measured at ∼15.5%±2%. However, this value should be considered a lower limit to the true binary fraction within the specified separation and mass ratio ranges in these clusters, given that complex and uncertain corrections for sensitivity and completeness have not been applied.

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Lunar occultations of Praesepe. II - Massachusetts

Cited by 6 publications

References 0 publications

Poking the Beehive from Space: K2 Rotation Periods for Praesepe

Poking the Beehive from Space: K2 Rotation Periods for Praesepe

The Interferometric Binary Epsilon Cancri in Praesepe: Precise Masses and Age

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

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