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
-
A determination of the space density and birth rate of hydrogen-line (DA) white dwarfs in the Galactic plane, based on the UVEX survey
We present a determination of the average space density and birth rate of hydrogen-line (DA) white dwarfs within a radius of 1 kpc around the Sun, based on an observational sample of 360 candidate white dwarfs with g < 19.5 and (g - r) < 0.4, selected from the UV-Excess (UVEX) survey of the northern Galactic plane, in combination with a theoretical
Verbeek, K. et al.Advertised on:
102013 -
A Black Hole Nova Obscured by an Inner Disk Torus.
Stellar-mass black holes (BHs) are mostly found in X-ray transients, a subclass of X-ray binaries that exhibit violent outbursts. None of the 50 Galactic BHs known show eclipses, which is surprising for a random distribution of inclinations. Swift J1357.2-0933 is a very faint X-ray transient detected in 2011. On the basis of spectroscopic evidence
Corral-Santana, J. M. et al.Advertised on:
32013 -
Exploring the circumstellar environment of the young eruptive star V2492 Cygni
Context. V2492 Cyg is a young eruptive star that went into outburst in 2010. The near-infrared color changes observed since the outburst peak suggest that the source belongs to a newly defined sub-class of young eruptive stars, where time-dependent accretion and variable line-of-sight extinction play a combined role in the flux changes. Aims: In
Vida, K. et al.Advertised on:
32013 -
A Three-dimensional View of the Remnant of Nova Persei 1901 (GK Per)
We present a kinematical study of the optical ejecta of GK Per. It is based on proper-motion measurements of 282 knots from ~20 images spanning 25 years. Doppler shifts are also computed for 217 knots. The combination of proper motions and radial velocities allows a unique three-dimensional view of the ejecta to be obtained. The main results are as
Liimets, T. et al.Advertised on:
122012 -
LOFT: the Large Observatory For X-ray Timing
The LOFT mission concept is one of four candidates selected by ESA for the M3 launch opportunity as Medium Size missions of the Cosmic Vision programme. The launch window is currently planned for between 2022 and 2024. LOFT is designed to exploit the diagnostics of rapid X-ray flux and spectral variability that directly probe the motion of matter
Feroci, M. et al.Advertised on:
92012 -
IPHAS J062746.41+014811.3: A Deeply Eclipsing Intermediate Polar
We present time-resolved photometry of a cataclysmic variable discovered in the Isaac Newton Telescope Photometric Hα Survey of the northern galactic plane, IPHAS J062746.41+014811.3, and classify the system as the fourth deeply eclipsing intermediate polar known with an orbital period of P orb = 8.16 hr and a spin period of P spin = 2210 s. The
Aungwerojwit, A. et al.Advertised on:
102012 -
Infrared Study of Fullerene Planetary Nebulae
We present a study of 16 planetary nebulae (PNe) where fullerenes have been detected in their Spitzer Space Telescope spectra. This large sample of objects offers a unique opportunity to test conditions of fullerene formation and survival under different metallicity environments because we are analyzing five sources in our own Galaxy, four in the
García-Hernández, D. A. et al.Advertised on:
122012 -
1RXS J0629-0335: A New Long-period Cataclysmic Variable
We present time-resolved spectroscopy and photometry of a new long-period cataclysmic variable (CV) identified from a combined X-ray (ROSAT) /infrared (2MASS) selection method, 1RXS J0629-0335. The preliminary orbital period of ˜9 h has been estimated from its radial velocity variation. We obtained photometry of 1RXS J0629-0335 throughout one month
Arjyotha, S. et al.Advertised on:
82009 -
The orbital period of V458 Vulpeculae, a post-double common-envelope nova
We present time-resolved optical spectroscopy of V458 Vulpeculae (Nova Vul 2007 No. 1) spread over a period of 15 months starting 301d after its discovery. Our data reveal radial-velocity variations in the HeII λ5412 and HeII λ4686 emission lines. A period analysis of the radial-velocity curves resulted in a period of 98.09647 +/- 0.00025min (0
Rodríguez-Gil, P. et al.Advertised on:
92010 -
The ongoing outburst of the new symbiotic star IPHASJ190832.31+051226.6
Aims: Eleven new symbiotic stars have recently been discovered with IPHAS, the INT Hα survey of the Northern Galactic plane. The star IPHAS J190832.31+051226.6 was proposed as an additional candidate on the basis of the existing spectrum. Here, we investigate the nature of this source by means of additional observations. Methods: Photometric data
Corradi, R. L. M. et al.Advertised on:
12010 -
The fight for accretion: discovery of intermittent mass transfer in BB Doradus in the low state
Our long-term photometric monitoring of southern nova-like cataclysmic variables with the 1.3-m Small and Moderate Aperture Research Telescope System (SMARTS) telescope found BB Doradus fading from V˜ 14.3 towards a deep low state at V˜ 19.3 in 2008 April. Here we present time-resolved optical spectroscopy of BB Dor in this faint state in 2009. The
Rodríguez-Gil, P. et al.Advertised on:
52012 -
Swift X-Ray and Ultraviolet Monitoring of the Classical Nova V458 Vul (Nova Vul 2007)
We describe the highly variable X-ray and UV emission of V458 Vul (Nova Vul 2007), observed by Swift between 1 and 422 days after outburst. Initially bright only in the UV, V458 Vul became a variable hard X-ray source due to optically thin thermal emission at kT = 0.64 keV with an X-ray band unabsorbed luminosity of 2.3 × 1034 erg s-1 during days
Ness, J.-U. et al.Advertised on:
52009 -
Post-common-envelope binaries from SDSS - V. Four eclipsing white dwarf main-sequence binaries
We identify SDSS011009.09+132616.1, SDSS030308.35+005444.1, SDSS143547.87+ 373338.5 and SDSS154846.00+405728.8 as four eclipsing white dwarf plus main-sequence (WDMS) binaries from the Sloan Digital Sky Survey (SDSS), and report on follow-up observations of these systems. SDSS0110+1326, SDSS1435+3733 and SDSS1548+4057 contain DA white dwarfs, while
Pyrzas, S. et al.Advertised on:
42009 -
Post-common envelope binaries from SDSS - VII. A catalogue of white dwarf-main sequence binaries
We present a catalogue of 1602 white-dwarf-main-sequence (WDMS) binaries from the spectroscopic Sloan Digital Sky Survey Data Release 6 (SDSS DR6). Among these, we identify 440 as new WDMS binaries. We select WDMS binary candidates by template fitting all 1.27 million DR6 spectra, using combined constraints in both χ2 and signal-to-noise ratio. In
Rebassa-Mansergas, A. et al.Advertised on:
22010 -
Post-common envelope binaries from SDSS - III. Seven new orbital periods
We present follow-up spectroscopy and photometry of 11 post-common envelope binary (PCEB) candidates identified from multiple Sloan Digital Sky Survey (SDSS) spectroscopy in an earlier paper. Radial velocity measurements using the NaIλλ8183.27, 8194.81 absorption doublet were performed for nine of these systems and provided measurements of six
Rebassa-Mansergas, A. et al.Advertised on:
112008 -
Post common envelope binaries from SDSS. XIII. Mass dependencies of the orbital period distribution
Context. Post-common-envelope binaries (PCEBs) consisting of a white dwarf (WD) and a main-sequence secondary star are ideal systems to constrain models of common-envelope (CE) evolution. Until very recently, observed samples of PCEBs have been too small to fully explore this potential, however the recently identified large and relatively
Zorotovic, M. et al.Advertised on:
122011 -
Post common envelope binaries from SDSS. XII. The orbital period distribution
Context. The complexity of the common-envelope phase and of magnetic stellar wind braking currently limits our understanding of close binary evolution. Because of their intrinsically simple structure, observational population studies of white dwarf plus main sequence (WDMS) binaries can potentially test theoretical models and constrain their
Nebot Gómez-Morán, A. et al.Advertised on:
122011 -
Post common envelope binaries from SDSS. VIII. Evidence for disrupted magnetic braking
Context. The standard prescription of angular momentum loss in compact binaries assumes magnetic braking to be very efficient as long as the secondary star has a radiative core, but to be negligible if the secondary star is fully convective. This prescription has been developed to explain the orbital period gap observed in the orbital period
Schreiber, M. R. et al.Advertised on:
42010 -
Post common envelope binaries from SDSS. IV. SDSS J121258.25-012310.1, a new eclipsing system
From optical photometry we show that SDSS J121258.25-012310.1 is a new eclipsing, post common-envelope binary with an orbital period of 8.06 h and an eclipse length of 23 min. We observed the object over 11 nights in different bands and determined the ephemeris of the eclipse to HJDmid = 2 454 104.7086(2) + 0.3358706(5) × E, where numbers in
Nebot Gómez-Morán, A. et al.Advertised on:
22009 -
Orbital periods of cataclysmic variables identified by the SDSS. VI. The 4.5-h period eclipsing system SDSS J100658.40+233724.4
We present time-resolved spectroscopy and photometry of SDSS J100658.40+233724.4, which we have discovered to be an eclipsing cataclysmic variable with an orbital period of 0.18591324 days (267.71507 min). The observed velocity amplitude of the secondary star is 276 ± 7 km s-1, which an irradiation correction reduces to 258 ± 12 km s-1. Doppler
Southworth, J. et al.Advertised on:
112009
