Absolute Properties of the Low-Mass Eclipsing Binary Cm Draconis

Morales, J. C.; Ribas, I.; Jordi, C.; Torres, Guillermo; Gallardo, José; Guinan, E. F.; Charbonneau, David; Wolf, M.; Latham, David W.; Anglada-Escudé, G.; Bradstreet, D. H.; Everett, Mark E.; O’Donovan, Francis T.; Mandushev, Georgi; Mathieu, Robert D.

doi:10.1088/0004-637x/691/2/1400

Cited by 170 publications

(241 citation statements)

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“…Searches for planet-mass objects from the light time effect were first proposed for low-mass eclipsing binaries by Doyle et al (1998) and have been performed in-depth on the system CM-Draconis, with ambiguous results to date (Deeg et al 2000(Deeg et al , 2008Morales et al 2009). They were soon followed by several studies of timing effects in transiting planet systems: TrES-1 , HD 189 733 (Miller-Ricci et al 2008b), HD 209 458 (Agol & Steffen 2007;Miller-Ricci et al 2008a), GJ 436 (Alonso et al 2008;Bean & Seifahrt 2008) and CoRoT1b (Bean 2009).…”

Section: Introductionmentioning

confidence: 99%

Transit timing analysis of the exoplanets TrES-1 and TrES-2

Deeg

Alonso

Belmonte

et al. 2009

A&A

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Aims. The aim of this work is a detailed analysis of transit light curves from TrES-1 and TrES-2, obtained over a period of three to four years, in order to search for variabilities in observed mid-transit times and to set constraints on the presence of additional third bodies. Methods. Using the IAC 80 cm telescope, we observed transits of TrES-1 and TrES-2 over several years. Based on these new data and previously published work, we studied the observed light curves and searched for variations in the difference between observed and calculated (based on a fixed ephemeris) transit times. To model possible transit timing variations, we used polynomials of different orders, simulated O-C diagrams corresponding to a perturbing third mass, and we used sinusoidal fits. For each model we calculated the χ 2 residuals and the false alarm probability (FAP).Results. For TrES-1, we can exclude planetary companions (>1 M ⊕ ) in the 3:2 and 2:1 MMRs having high FAPs based on our transit observations from the ground. Likewise, a light time effect caused, e.g., by a 0.09 M mass star at a distance of 7.8 AU is possible. As for TrES-2, we find a better ephemeris of T c = 2 453 957.63512(28) + 2.4706101(18) × Epoch and a good fit for a sine function with a period of 0.2 days, compatible with a moon around TrES-2 and an amplitude of 57 s, but it is not a uniquely low χ 2 value that would indicate a clear signal. In both cases, TrES-1 and TrES-2, we are able to put upper constraints on the presence of additional perturbers masses. We also conclude that any sinusoidal variations that might be indicative of exomoons need to be confirmed with higher statistical significance by further observations, noting that TrES-2 is in the field-of-view of the Kepler Space Telescope.

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Section: Introductionmentioning

confidence: 99%

Transit timing analysis of the exoplanets TrES-1 and TrES-2

Deeg

Alonso

Belmonte

et al. 2009

A&A

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“…One of the brightest and best-studied M-M EBs, CM Draconis (V = 12.87) (Eggen & Sandage 1967), has been the target of extensive characterization allowing the measurement of the system's parameters to ≤1% precision (Lacy 1977;Metcalfe et al 1996;Morales et al 2009). The short orbital period (∼1.27 days) suggests that the rotation period of the two stars is synchronized with the orbital period of the binary (Morales et al 2009). However, the stellar radii in CM Dra are 5-7% larger than predicted by theoretical models (Feiden & Chaboyer 2014).…”

Section: Introductionmentioning

confidence: 99%

A Bright Short Period M-M Eclipsing Binary from the KELT Survey: Magnetic Activity and the Mass–Radius Relationship for M Dwarfs

Lubin

Rodriguez

Zhou

et al. 2017

ApJ

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We report the discovery of KELT J041621-620046, a moderately bright (J∼10.2) M dwarf eclipsing binary system at a distance of 39±3 pc. KELT J041621-620046 was first identified as an eclipsing binary using observations from the Kilodegree Extremely Little Telescope (KELT) survey. The system has a short orbital period of ∼1.11 days and consists of components with M 1 = 0.447 +0.034 R ⊙ and R 2 = 0.453 ± 0.017 R ⊙ . Full system and orbital properties were determined (to ∼10% error) by conducting an EBOP global modeling of the high precision photometric and spectroscopic observations obtained by the KELT Follow-up Network. Each star is larger by 17-28% and cooler by 4-10% than predicted by standard (non-magnetic) stellar models. Strong Hα emission indicates chromospheric activity in both stars. The observed radii and temperature discrepancies for both components are more consistent with those predicted by empirical relations that account for convective suppression due to magnetic activity.

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“…But evolutionary models are very uncertain for ages 1 Myr (Baraffe et al 2002;Wuchterl 2005;Marley et al 2007;Mohanty et al 2007) and, in any case, the age determination and physical natures of these very young objects is subject to debate (Stassun et al 2008. Furthermore, the mutual capture of BDs and LMS into binary systems after each component formed independently is probably too infrequent to account for the large number of eclipsing LMS binaries with either temperature reversals or inflated radii (Guenther et al 2001;Coughlin & Shaw 2007;Ribas et al 2008;Çakırlı et al 2009;Morales et al 2009). …”

Section: Introductionmentioning

confidence: 99%

Tidal effects on brown dwarfs: application to the eclipsing binary 2MASS J05352184-0546085

Heller¹,

Jackson²,

Barnes

et al. 2010

A&A

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Context. 2MASS J05352184−0546085 (2M0535−05) is the only known eclipsing brown dwarf (BD) binary, and so may serve as a benchmark for models of BD formation and evolution. However, theoretical predictions of the system's properties seem inconsistent with observations: i) the more massive (primary) component is observed to be cooler than the less massive (secondary) one; ii) the secondary is more luminous (by ≈10 24 W) than expected. Previous explanations for the temperature reversal have invoked reduced convective efficiency in the structure of the primary, connected to magnetic activity and to surface spots, but these explanations cannot account for the enhanced luminosity of the secondary. Previous studies also considered the possibility that the secondary is younger than the primary. Aims. We study the impact of tidal heating to the energy budget of both components to determine if it can account for the observed temperature reversal and the high luminosity of the secondary. We also compare various plausible tidal models to determine a range of predicted properties. Methods. We apply two versions of two different, well-known models for tidal interaction, respectively: i) the "constant-phase-lag" model; and ii) the "constant-time-lag" model and incorporate the predicted tidal heating into a model of BD structure. The four models differ in their assumptions about the rotational behavior of the bodies, the system's eccentricity and putative misalignments ψ between the bodies' equatorial planes and the orbital plane of the system. Results. The contribution of heat from tides in 2M0535−05 alone may only be large enough to account for the discrepancies between observation and theory in an unlikely region of the parameter space. The tidal quality factor Q BD of BDs would have to be 10 3.5 and the secondary needs a spin-orbit misalignment of 50 • . However, tidal synchronization time scales for 2M0535−05 restrict the tidal dissipation function to log(Q BD ) 4.5 and rule out intense tidal heating in 2M0535−05. We provide the first constraint on Q for BDs. Conclusions. Tidal heating alone is unlikely to be responsible for the surprising temperature reversal within 2M0535−05. But an evolutionary embedment of tidal effects and a coupled treatment with the structural evolution of the BDs is necessary to corroborate or refute this result. The heating could have slowed down the BDs' shrinking and cooling processes after the birth of the system ≈1 Myr ago, leading to a feedback between tidal inflation and tidal heating. Observations of old BD binaries and measurements of the Rossiter-McLaughlin effect for 2M0535−05 can provide further constraints on Q BD .

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Absolute Properties of the Low-Mass Eclipsing Binary Cm Draconis

Cited by 170 publications

References 54 publications

Transit timing analysis of the exoplanets TrES-1 and TrES-2

Transit timing analysis of the exoplanets TrES-1 and TrES-2

A Bright Short Period M-M Eclipsing Binary from the KELT Survey: Magnetic Activity and the Mass–Radius Relationship for M Dwarfs

Tidal effects on brown dwarfs: application to the eclipsing binary 2MASS J05352184-0546085

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