ellc: A fast, flexible light curve model for detached eclipsing binary stars and transiting exoplanets

Maxted, P. F. L.

doi:10.1051/0004-6361/201628579

Cited by 149 publications

(121 citation statements)

References 54 publications

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“…pydata.org/index.html), allesfitter (Günther & Daylan, in prep. ), ellc (Maxted 2016), aflare , dynesty (https://github.com/joshspeagle/ dynesty), corner (Foreman-Mackey 2016).…”

Section: Large Flares and Changes To The Rotational Modulation Patternmentioning

confidence: 99%

Complex Rotational Modulation of Rapidly Rotating M Stars Observed with TESS

Zhan

Günther

Rappaport

et al. 2019

ApJ

122

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We have searched for short periodicities in the light curves of stars with T eff cooler than 4000 K made from 2-minute cadence data obtained in TESS sectors 1 and 2. Herein we report the discovery of 10 rapidly rotating M-dwarfs with highly structured rotational modulation patterns among 371 M dwarfs found to have rotation periods less than 1 day. Star-spot models cannot explain the highly structured periodic variations which typically exhibit between 10 and 40 Fourier harmonics. A similar set of objects was previously reported following K2 observations of the Upper Scorpius association (Stauffer et al. 2017). We examine the possibility that the unusual structured light-curves could stem from absorption by charged dust particles that are trapped in or near the stellar magnetosphere. We also briefly explore the possibilities that the sharp structured features in the lightcurves are produced by extinction by coronal gas, by beaming of the radiation emitted from the stellar surface, or by occultations of spots by a dusty ring that surrounds the star. The latter is perhaps the most promising of these scenarios. Most of the structured rotators display flaring activity, and we investigate changes in the modulation pattern following the largest flares. As part of this study, we also report the discovery of 17 rapidly rotating M-dwarfs with rotational periods below 4 hr, of which the shortest period is 1.63 hr.

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“…pydata.org/index.html), allesfitter (Günther & Daylan, in prep. ), ellc (Maxted 2016), aflare , dynesty (https://github.com/joshspeagle/ dynesty), corner (Foreman-Mackey 2016).…”

Section: Large Flares and Changes To The Rotational Modulation Patternmentioning

confidence: 99%

Complex Rotational Modulation of Rapidly Rotating M Stars Observed with TESS

Zhan

Günther

Rappaport

et al. 2019

ApJ

122

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“…The radial velocity and light curves were modeled using the ellc binary star model (Maxted 2016) 2 . An MCMC sampler (emcee; Foreman-Mackey et al 2013), was used to fit the transit light-curves and radial velocities in a framework similar to that described in Triaud et al (2013).…”

Section: Model Of the Datamentioning

confidence: 99%

The EBLM project

Boetticher

Triaud

Queloz

et al. 2017

A&A

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We report the discovery of an eclipsing binary system with mass-ratio q ∼ 0.07. After identifying a periodic photometric signal received by WASP, we obtained CORALIE spectroscopic radial velocities and follow-up light curves with the Euler and TRAPPIST telescopes. From a joint fit of these data we determine that EBLM J0555-57 consists of a sun-like primary star that is eclipsed by a low-mass companion, on a weakly eccentric 7.8-day orbit. Using a mass estimate for the primary star derived from stellar models, we determine a companion mass of 85 ± 4 M Jup (0.081 M ) and a radius of 0.84 +0.14 −0.04 R Jup (0.084 R ) that is comparable to that of Saturn. EBLM J0555-57Ab has a surface gravity log g 2 = 5.50 +0.03 −0.13 and is one of the densest non-stellar-remnant objects currently known. These measurements are consistent with models of low-mass stars.Key words. binaries: eclipsing -binaries: spectroscopic -stars: low-mass -techniques: spectroscopic -techniques: photometricstars: individual: EBLM J0555-57AbEclipsing binary stars enable empirical measurements of the stellar mass-radius relation. The low-mass regime, down to the hydrogen-burning mass limit, is poorly constrained by measurements of mass and radius, but is of particular relevance to the study of exoplanets. Stars with masses below 0.25 M are the most common stellar objects (Kroupa 2001;Chabrier 2003;Henry et al. 2006) and prove to be excellent candidates for the detection of Earth-sized planets (Berta- Gillon et al. 2016Gillon et al. , 2017Luger et al. 2017) and their atmospheric characterization (de Wit et al. 2016). Determining the properties of exoplanets requires an accurate knowledge of their host star parameters, in particular the stellar mass. This motivates the study of low-mass eclipsing binaries (henceforth EBLMs; Triaud et al. 2013;Gómez Maqueo Chew et al. 2014), to empirically measure the mass-radius relation. In this context, we report our results on the eclipsing binary EBLM J0555-57. The system was detected by the Wide Angle Search for PlanetsThe photometry tables and radial velocities are only available at the CDS and on demand via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)

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“…Following the method from Burdge et al (2019), we use a python implementation of Multinest (Feroz et al 2009) to measure the radial-velocity covariances. The sample lightcurves were generated using the ellc package (Maxted 2016), where the lightcurves depend on the mid-eclipse time of the primary eclipse, t 0 , the inclination, i, the mass ratio, q = m 2 m 1 , the ratio of the radii to the semi-major axis, r 1 = R 1 /a, r 2 = R 2 /a, and the surface brightness ratio, J. The first object is treated as spherical, the second is assumed to have a Roche geometry.…”

Section: Resultsmentioning

confidence: 99%

ZTF J1901+5309: a 40.6-min orbital period eclipsing double white dwarf system

Coughlin

Burdge

Phinney

et al. 2020

Monthly Notices of the Royal Astronomical Society: Letters

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The Zwicky Transient Facility has begun to discover binary systems with orbital periods that are less than 1 hr. Combined with dedicated follow-up systems, which allow for high-cadence photometry of these sources, systematic confirmation and characterization of these sources are now possible. Here, we report the discovery of ZTF J190125.42+530929.5, a 40.6 min orbital period, eclipsing double white-dwarf binary. Both photometric and spectroscopic modeling confirm its nature, yielding an estimated inclination of i = 86.2 +0.6 −0.2 degrees and primary and secondary effective temperatures of T eff = 28, 000 +500 −500 K and T eff = 17, 600 +400 −400 K respectively. This system adds to a growing list of sources for future gravitational-wave detectors and contributes to the demographic analysis of double degenerates.

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ellc: A fast, flexible light curve model for detached eclipsing binary stars and transiting exoplanets

Cited by 149 publications

References 54 publications

Complex Rotational Modulation of Rapidly Rotating M Stars Observed with TESS

Complex Rotational Modulation of Rapidly Rotating M Stars Observed with TESS

The EBLM project

ZTF J1901+5309: a 40.6-min orbital period eclipsing double white dwarf system

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