Search for light curve modulations among<i>Kepler</i>candidates

Lillo-Box, J.; Ribas, Álvaro; Barrado, D.; Merın, Bruno; Bouy, H.

doi:10.1051/0004-6361/201528002

Cited by 8 publications

(4 citation statements)

References 41 publications

(57 reference statements)

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“…The reflection, ellipsoidal, and beaming signals for our best-fit parameters are at least one order of magnitude less than the observed modulations (Lillo-Box et al 2016). Gravity darkening, according to von Zeipel Theorem (von Zeipel 1924), is significant in stars that are hot enough to have radiative envelopes (earlier than F type), which is not the case for T-Cyg1-12664.…”

Section: Out-of-eclipse Modulationsmentioning

confidence: 63%

Magnetic Inflation and Stellar Mass. I. Revised Parameters for the Component Stars of the Kepler Low-mass Eclipsing Binary T-Cyg1-12664

Han

Muirhead

Swift³

et al. 2017

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Several low-mass eclipsing binary stars show larger than expected radii for their measured mass, metallicity, and age. One proposed mechanism for this radius inflation involves inhibited internal convection and starspots caused by strong magnetic fields. One particular eclipsing binary, T-Cyg1-12664, has proven confounding to this scenario. Çakırlı et al. measured a radius for the secondary component that is twice as large as model predictions for stars with the same mass and age, but a primary mass that is consistent with predictions. Iglesias-Marzoa et al. independently measured the radii and masses of the component stars and found that the radius of the secondary is not in fact inflated with respect to models, but that the primary is, which is consistent with the inhibited convection scenario. However, in their mass determinations, Iglesias-Marzoa et al. lacked independent radial velocity measurements for the secondary component due to the star's faintness at optical wavelengths. The secondary component is especially interesting, as its purported mass is near the transition from partially convective to a fully convective interior. In this article, we independently determined the masses and radii of the component stars of T-Cyg1-12664 using archival Kepler data and radial velocity measurements of both component stars obtained with IGRINS on the Discovery Channel Telescope and NIRSPEC and HIRES on the Keck Telescopes. We show that neither of the component stars is inflated with respect to models. Our results are broadly consistent with modern stellar evolutionary models for main-sequence M dwarf stars and do not require inhibited convection by magnetic fields to account for the stellar radii.

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Section: Out-of-eclipse Modulationsmentioning

confidence: 63%

Magnetic Inflation and Stellar Mass. I. Revised Parameters for the Component Stars of the Kepler Low-mass Eclipsing Binary T-Cyg1-12664

Han

Muirhead

Swift³

et al. 2017

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“…The Kepler mission uncovered another four transiting brown dwarfs: Kepler-39b (Bouchy et al 2011a), KOI-205b (Díaz et al 2013), KOI-415b (Moutou et al 2013), and KOI-189b (Díaz et al 2014b). Additionally KOI-554b and KOI-3728b have masses, measured via light curve modulations, just above 80 M J , putting them very close to the brown dwarf regime (Lillo-Box et al 2016). However the bulk of planet candidates discovered by the Kepler space mission (Borucki et al 2010) have measured radii but not masses, so are not able to provide a constraint on the brown dwarf population due to the radius degeneracy between gas giants and brown dwarfs.…”

Section: Introductionmentioning

confidence: 99%

EPIC 201702477b: A TRANSITING BROWN DWARF FROM K2 IN A 41 DAY ORBIT

Hojjatpanah¹,

Santerne²,

Dragomir³

et al. 2016

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We report the discovery of EPIC 201702477b, a transiting brown dwarf in a long period (40.73691±0.00037 day) and eccentric (e = 0.2281±0.0026) orbit. This system was initially reported as a planetary candidate based on two transit events seen in K2 Campaign 1 photometry and later validated as an exoplanet candidate. We confirm the transit and refine the ephemeris with two subsequent ground-based detections of the transit using the Las Cumbres Observatory Global Telescope 1 m telescope network. We rule out any transit timing variations above the level of ∼30 s. Using high precision radial velocity measurements from HARPS and SOPHIE we identify the transiting companion as a brown dwarf with a mass, radius, and bulk density of 66.9±1.7 M J , 0.757±0.065 R J , and 191±51 g cm −3 respectively. EPIC 201702477b is the smallest radius brown dwarf yet discovered, with a mass just below the H-burning limit. It has the highest density of any planet, substellar mass object, or main-sequence star discovered so far. We find evidence in the set of known transiting brown dwarfs for two populations of objects-high mass brown dwarfs and low mass brown dwarfs. The highermass population have radii in very close agreement to theoretical models, and show a lower-mass limit around 60 M J . This may be the signature of mass-dependent ejection of systems during the formation process.

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“…The relativistic beaming signal in stars are already well documented and actively searched for (Loeb & Gaudi 2003;van Kerkwijk et al 2010;Bloemen et al 2011;Lillo-Box et al 2016). However, the crux of this paper is the possibility of observing beaming signals in the companion.…”

Section: Beaming Of the Companionmentioning

confidence: 99%

“…There are many systems we could observe or imagine where relativistic beaming could be significant, such as binary star systems (van Kerkwijk et al 2010), brown dwarves (Lillo-Box et al 2016) or compact objects (Bloemen et al 2011) and is theorized as being a plausible method for detecting stellar mass black holes in binaries (Masuda & Hotokezaka 2018). For the purpose of discussion in this work I will focus on a specific sample as a case study -the current known population of exoplanets.…”

Section: Observational Possibilitiesmentioning

confidence: 99%

The beam balance – measuring binary systems via relativistic beaming signals from stars and their companions

Penoyre

2019

Monthly Notices of the Royal Astronomical Society

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In this paper I show that the concept of relativistic beaming -the process by which light emitted by a fast moving sources is lensed towards the direction of motioncan be easily extended to model the signal from both the star and any secondary companions.Most companions will be cooler and less massive than their host star. Their lower mass leads to faster orbital velocities, and thus a potentially larger beaming effect. The lower temperature will mean that most of their light is emitted at longer wavelengths, where the relative photometric dominance of the primary is reduced.Thus for some systems, the secondary companion can be the main contributor to observed relativistic beaming signals at long wavelengths. Furthermore, if the system is observed over a range of wavelengths we can independently constrain the temperature of the companion, and the mass and radius ratio of the binary.To conclude I discuss the current and future observational prospects of this signal, using the properties of known exoplanets to show that such a signal may be observable by upcoming surveys.

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Search for light curve modulations amongKeplercandidates

Cited by 8 publications

References 41 publications

Magnetic Inflation and Stellar Mass. I. Revised Parameters for the Component Stars of the Kepler Low-mass Eclipsing Binary T-Cyg1-12664

Magnetic Inflation and Stellar Mass. I. Revised Parameters for the Component Stars of the Kepler Low-mass Eclipsing Binary T-Cyg1-12664

EPIC 201702477b: A TRANSITING BROWN DWARF FROM K2 IN A 41 DAY ORBIT

The beam balance – measuring binary systems via relativistic beaming signals from stars and their companions

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