Grants related:
General
The study of binary stars is essential to stellar astrophysics. A large number of stars form and evolve within binary systems. Therefore, their study is fundamental to understand stellar and galactic evolution. Particularly relevant is that binary systems are still the best source of precise stellar mass and radius measurements.
Research lines:
- Determination of absolute parameters of Algol-type eclipsing binaries. In 2006 we started a new project to derive accurate masses and radii of low-mass eclipsing binaries of spectral type M. These will be confronted with theoretical predictions for the lower main sequence.
- Study of the structure and evolution of cataclysmic variables (CVs). Among the main goals we highlight a fundamental test of the current evolution theory, which will observationally prove or discard several of its predictions. In doing so, population studies on both the observed minimum orbital period region (~ 80 min) and the upper boundary of the period gap (in the 3-4.5 hour orbital period range) are being performed. On the other hand, our research has demonstrated the existence of a huge pile-up of intrinsically very luminous CVs (with the highest mass transfer rates known), with orbital periods just above 3 hours, in apparent contradiction to theoretical expectations. The masses of these systems are being determined using ToO time in 8-m class telescopes as VLT and Gemini, and the 10.4-m GTC when a system falls into a low brightness state characterised by the quenching of the mass transfer from the donor star to the white dwarf.
- Study of central binary stars of planetary nebulae. One plausible effect leading to bipolar shapes in planetary nebulae is the presence of a progenitor binary star in their centres, containing at least one white dwarf. This project is aimed at finding a significant "bipolarity-binarity" correlation within bipolar planetary nebulae. Further, the history of the mass ejection episodes will give clues to the common-envelope stage, still poorly understood.
- In mid-2017 we started another research line in the field of white dwarfs: the study of post-planetary remnants around these stars, which can greatly benefit from our studies of accretion discs in cataclysmic variables.
Members
Results
- Many white dwarf stars show signs of having accreted smaller bodies, implying that they may host planetary systems. A small number of these systems contain gaseous debris discs, visible through emission lines. We found a stable 123.4-minute periodic variation in the strength and shape of the Ca II emission line profiles originating from the debris disc around the white dwarf SDSS J122859.93+104032.9. We interpret this short-period signal as the signature of a solid-body planetesimal held together by its internal strength. Results published in Science.
- Discovery of a giant bubble-like shell around M31N 2008–12a, the recurrent nova with the shortest eruption recurrence period (one year). Results published in Nature.
- A fast GTC/OSIRIS spectrophotometric study of the white dwarf WD 1145+017 has been published in Monthly Notices of the Royal Astronomical Society that reports confirmation of the evolution of the periodic transits that occur every 4.5 hours. The deepest transit detected to date has been modelled with six equally spaced fragments of the disrupting planetesimal.
- In 2018 an International Time Programme for follow-up of gravitational wave events was awarded (PI Jonker, SRON, The Netherlands). Several members of the projects are co-Is. Rodríguez-Gil will serve as chair on the Executive Committee.
Scientific activity
Related publications
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SDSS unveils a population of intrinsically faint cataclysmic variables at the minimum orbital period
We discuss the properties of 137 cataclysmic variables (CVs) which are included in the Sloan Digital Sky Survey (SDSS) spectroscopic data base, and for which accurate orbital periods have been measured. 92 of these systems are new discoveries from SDSS and were followed-up in more detail over the past few years. 45 systems were previously
Gänsicke, B. T. et al.Advertised on:
82009 -
Observations of the 599 Hz Accreting X-Ray Pulsar IGR J00291+5934 during the 2004 Outburst and in Quiescence
We report on optical and near-infrared observations obtained during and after the 2004 December discovery outburst of the X-ray transient and accretion-powered millisecond pulsar IGR J00291+5934. Our observations monitored the evolution of the brightness and the spectral properties of IGR J00291+5934 during the outburst decay toward quiescence. We
Torres, M. A. P. et al.Advertised on:
12008 -
HS 2325+8205 - An Ideal Laboratory for Accretion Disk Physics
We identify HS 2325+8205 as an eclipsing, frequently outbursting, dwarf nova with an orbital period of Porb = 279.841731(5) minutes. Spectroscopic observations are used to derive the radial velocity curve of the secondary star from absorption features and also from the Hα emission lines, originating from the accretion disk, yielding Ksec = Kabs =
Pyrzas, S. et al.Advertised on:
32012 -
Evidence for a black hole in the X-ray transient XTE J1859+226
We present the results of time-resolved optical photometry and spectroscopy of the X-ray transient XTE J1859+226 (V406 Vul). Photometric observations taken during 2000 and 2008 reveal the presence of the secondary star's ellipsoidal modulation. Further photometry obtained in 2010 shows the system ≃1 mag brighter than its quiescence level and the
Corral-Santana, J. M. et al.Advertised on:
52011 -
A flickering study of nova-like systems KR Aur and UU Aqr
We present a study of the flickering activity in two nova-like systems, KR Aur and UU Aqr. We applied a statistical model of flickering simulations in accretion discs based on turbulent angular momentum transport between two adjacent rings with an exponential distribution of the turbulence dimension scale. The model is based on a steady-state disc
Dobrotka, A. et al.Advertised on:
32012 -
The kinematics of the quadrupolar nebula M 1-75 and the identification of its central star
Context. The link between how bipolar planetary nebulae are shaped and their central stars is still poorly understood. Aims: This paper investigates the kinematics and shaping of the multipolar nebula M 1-75, and briefly discusses the location and nature of its central star. Methods: Fabry-Perot data from GHαFAS on the WHT that samples the Doppler
Santander-García, M. et al.Advertised on:
92010 -
An eclipsing post-common-envelope binary in the field of the Kepler mission
We present a new eclipsing post-common-envelope binary, identified inside the Kepler field prior to the launch of the spacecraft. Multifilter photometry and radial velocity data are analysed with an eclipsing-binary modelling code to determine the physical parameters of the binary. Spectra of the system within the primary eclipse and uneclipsed
Almenara, J. M. et al.Advertised on:
32012 -
Variability of the blazar 4C 38.41 (B3 1633+382) from GHz frequencies to GeV energies
Context. After years of modest optical activity, the quasar-type blazar 4C 38.41 (B3 1633+382) experienced a large outburst in 2011, which was detected throughout the entire electromagnetic spectrum, renewing interest in this source. Aims: We present the results of low-energy multifrequency monitoring by the GLAST-AGILE Support Program (GASP) of
Raiteri, C. M. et al.Advertised on:
92012 -
The outburst and nature of two young eruptive stars in the North America/Pelican Nebula Complex
Context. The sudden optical brightening of two young stellar objects, HBC 722 and VSX J205126.1+440523, located in the North America/Pelican Nebula Complex, was announced in August 2010. Early photometric and spectroscopic observations of these objects indicated that they may belong to the FUor or EXor class of young eruptive stars. The eruptions
Kóspál, Á. et al.Advertised on:
32011 -
The 2008 Outburst of EX Lup—Silicate Crystals in Motion
EX Lup is the prototype of the EXor class of eruptive young stars. These objects show optical outbursts which are thought to be related to runaway accretion onto the star. In a previous study we observed in situ crystal formation in the disk of EX Lup during its latest outburst in 2008, making the object an ideal laboratory to investigate
Juhász, A. et al.Advertised on:
12012 -
Near-infrared study of the stellar population of Sh2-152
Context. The discovery of new massive star clusters and massive stellar populations in previously known clusters in our Galaxy by means of infrared studies has changed our view of the Milky Way from an inactive to an active star-forming machine. Within this scenario, we present a near-infrared spectrophotometric study of the stellar content of the
Ramírez-Alegría, S. et al.Advertised on:
112011 -
Near-infrared spectroscopy in NGC 7538
Aims: The characterisation of the stellar population in young high-mass star-forming regions allows fundamental cluster properties like distance and age to be constrained. These are essential when using high-mass clusters as probes for conducting Galactic studies. Methods: NGC 7538 is a star-forming region with an embedded stellar population
Puga, E. et al.Advertised on:
72010 -
Mid-infrared Spectral Variability Atlas of Young Stellar Objects
Optical and near-infrared variability is a well-known property of young stellar objects. However, a growing number of recent studies claim that a considerable fraction of them also exhibit mid-infrared flux changes. With the aim of studying and interpreting variability on a decadal timescale, here we present a mid-infrared spectral atlas containing
Kóspál, Á. et al.Advertised on:
82012 -
Infrared and Optical Polarimetry around the Low-mass Star-forming Region NGC 1333 IRAS 4A
We performed J- and R-band linear polarimetry with the 4.2 m William Herschel Telescope at the Observatorio del Roque de los Muchachos and with the 1.6 m telescope at the Observatório do Pico dos Dias, respectively, to derive the magnetic field geometry of the diffuse molecular cloud surrounding the embedded protostellar system NGC 1333 IRAS 4A. We
Alves, Felipe O. et al.Advertised on:
72011 -
HH 223: a parsec-scale H2 outflow in the star-forming region L723
Context. The dark cloud Lynds 723 (L723) is a low-mass star-forming region where one of the few known cases of a quadrupolar CO outflow has been reported. Two recent works have found that the radio continuum source VLA 2, towards the centre of the CO outflow, is actually a multiple system of young stellar objects (YSOs). Several line-emission
López, R. et al.Advertised on:
112010 -
A Peculiar Young Eruptive Star in the Dark Cloud Lynds 1340
We conducted a long-term optical photometric and spectroscopic monitoring of the strongly variable, accreting young sun-like star [KOS94] HA11, associated with the dark cloud Lynds 1340 that exhibited large amplitude (5-6 mag in the I C band) brightness variations on 2-3 years timescales, flat spectral energy distribution (SED), and extremely
Kun, M. et al.Advertised on:
52011
