Start year
1988
Organizational Unit
Organizing institutions
Grants related:
General
Description
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
Principal investigator
Pablo
Rodríguez Gil
Project staff
Manuel Ángel
Pérez Torres
Tariq
Shahbaz
Dr.
Vikram Dhillon
Ignacio
González Martínez-Pais
Montserrat
Armas Padilla
Teodoro
Muñoz Darias
Jorge
Casares Velázquez
María Jesús
Arevalo Morales
Carlos
Lázaro Hernando
Collaborators
Dr.
B. T. Gänsicke
Dr.
T. R. Marsh
Dr.
R. Iglesias Marzoa
Dr.
M. López Morales
Dr.
P. Abraham
Dr.
D. Steeghs
Dr.
E. Breedt
Dr.
L. Schmidtobreick
Dr.
J. M. Corral Santana
Dr.
S. B. Potter
Dr.
W. Skidmore
Dr.
P. Hakala
Prof.
P. G. Jonker
Dr.
K. S. Long
Dr.
G. Sala
Dr.
Nancy Elías de la Rosa
Dr.
M. Hernanz
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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Discovery of an old nova shell surrounding the cataclysmic variable V1315 AqlFollowing our tentative discovery of a faint shell around V1315 Aql reported in Sahman et al., we undertook deep Hα imaging and intermediate-resolution spectroscopy of the shell. We find that the shell has its geometric centre located on V1315 Aql. The mass, spectral features, and density of the shell are consistent with other nova shells, ratherSahman, D. I. et al.
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72018 -
Breaking the Habit: The Peculiar 2016 Eruption of the Unique Recurrent Nova M31N 2008-12aSince its discovery in 2008, the Andromeda galaxy nova M31N 2008-12a has been observed in eruption every single year. This unprecedented frequency indicates an extreme object, with a massive white dwarf and a high accretion rate, which is the most promising candidate for the single-degenerate progenitor of a Type Ia supernova known to date. TheHenze, M. et al.
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42018 -
The sdB pulsating star V391 Peg and its putative giant planet revisited after 13 years of time-series photometric dataV391 Peg (alias HS 2201+2610) is a subdwarf B (sdB) pulsating star that shows both p- and g-modes. By studying the arrival times of the p-mode maxima and minima through the O-C method, in a previous article the presence of a planet was inferred with an orbital period of 3.2 years and a minimum mass of 3.2 MJup. Here we present an updated O-CMolnar, L. et al.
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42018 -
High-speed photometry of Gaia14aae: an eclipsing AM CVn that challenges formation modelsAM CVn-type systems are ultracompact, hydrogen-deficient accreting binaries with degenerate or semidegenerate donors. The evolutionary history of these systems can be explored by constraining the properties of their donor stars. We present high-speed photometry of Gaia14aae, an AM CVn with a binary period of 49. 7 min and the first AM CVn in whichGreen, M. J. et al.
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52018 -
280 one-opposition near-Earth asteroids recovered by the EURONEAR with the Isaac Newton TelescopeContext. One-opposition near-Earth asteroids (NEAs) are growing in number, and they must be recovered to prevent loss and mismatch risk, and to improve their orbits, as they are likely to be too faint for detection in shallow surveys at future apparitions. Aims: We aimed to recover more than half of the one-opposition NEAs recommended forVaduvescu, O. et al.
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12018 -
Blazar spectral variability as explained by a twisted inhomogeneous jetBlazars are active galactic nuclei, which are powerful sources of radiation whose central engine is located in the core of the host galaxy. Blazar emission is dominated by non-thermal radiation from a jet that moves relativistically towards us, and therefore undergoes Doppler beaming. This beaming causes flux enhancement and contraction of theRaiteri, C. M. et al.
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122017 -
The OmegaWhite Survey for Short-period Variable Stars. V. Discovery of an Ultracompact Hot Subdwarf Binary with a Compact Companion in a 44-minute OrbitWe report the discovery of the ultracompact hot subdwarf (sdOB) binary OW J074106.0–294811.0 with an orbital period of {P}{orb}=44.66279+/- 1.16× {10}-4 minutes, making it the most compact hot subdwarf binary known. Spectroscopic observations using the VLT, Gemini and Keck telescopes revealed a He-sdOB primary with an intermediate helium abundanceKupfer, T. et al.
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122017 -
The planetary nebula IC 4776 and its post-common-envelope binary central starWe present a detailed analysis of IC 4776, a planetary nebula displaying a morphology believed to be typical of central star binarity. The nebula is shown to comprise a compact hourglass-shaped central region and a pair of precessing jet-like structures. Time-resolved spectroscopy of its central star reveals a periodic radial velocity variabilitySowicka, P. et al.
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112017 -
Dissecting the long-term emission behaviour of the BL Lac object Mrk 421We report on long-term multiwavelength monitoring of blazar Mrk 421 by the GLAST-AGILE Support Program of the Whole Earth Blazar Telescope (GASP-WEBT) collaboration and Steward Observatory, and by the Swift and Fermi satellites. We study the source behaviour in the period 2007-2015, characterized by several extreme flares. The ratio between theCarnerero, M. I. et al.
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122017 -
The white dwarf binary pathways survey - II. Radial velocities of 1453 FGK stars with white dwarf companions from LAMOST DR 4We present the second paper of a series of publications aiming at obtaining a better understanding regarding the nature of type Ia supernovae (SN Ia) progenitors by studying a large sample of detached F, G and K main-sequence stars in close orbits with white dwarf companions (i.e. WD+FGK binaries). We employ the Large Sky Area Multi-Object FibreRebassa-Mansergas, A. et al.
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122017 -
Multiwavelength observations of a VHE gamma-ray flare from PKS 1510-089 in 2015Context. PKS 1510-089 is one of only a few flat spectrum radio quasars detected in the very-high-energy (VHE, > 100 GeV) gamma-ray band. Aims: We study the broadband spectral and temporal properties of the PKS 1510-089 emission during a high gamma-ray state. Methods: We performed VHE gamma-ray observations of PKS 1510-089 with the Major AtmosphericAhnen, M. L. et al.
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72017 -
Testing the white dwarf mass-radius relationship with eclipsing binariesWe present high-precision, model-independent, mass and radius measurements for 16 white dwarfs in detached eclipsing binaries and combine these with previously published data to test the theoretical white dwarf mass-radius relationship. We reach a mean precision of 2.4 per cent in mass and 2.7 per cent in radius, with our best measurements reachingParsons, S. G. et al.
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102017 -
Two white dwarfs in ultrashort binaries with detached, eclipsing, likely sub-stellar companions detected by K2Using data from the extended Kepler mission in K2 Campaign 10, we identify two eclipsing binaries containing white dwarfs with cool companions that have extremely short orbital periods of only 71.2 min (SDSS J1205-0242, a.k.a. EPIC 201283111) and 72.5 min (SDSS J1231+0041, a.k.a. EPIC 248368963). Despite their short periods, both systems areParsons, S. G. et al.
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102017 -
PTF1 J085713+331843, a new post-common-envelope binary in the orbital period gap of cataclysmic variablesWe report the discovery and analysis of PTF1 J085713+331843, a new eclipsing post-common-envelope detached white-dwarf-red-dwarf binary with a 2.5 h orbital period discovered by the Palomar Transient Factory. ULTRACAM multicolour photometry over multiple orbital periods reveals a light curve with a deep flat-bottomed primary eclipse and a strongLaher, R. et al.
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72017 -
SDSS J105754.25+275947.5: a period-bounce eclipsing cataclysmic variable with the lowest-mass donor yet measuredWe present high-speed, multicolour photometry of the faint, eclipsing cataclysmic variable (CV) SDSS J105754.25+275947.5. The light from this system is dominated by the white dwarf. Nonetheless, averaging many eclipses reveals additional features from the eclipse of the bright spot. This enables the fitting of a parametrized eclipse model to theseMcAllister, M. J. et al.
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52017 -
A VLT-ULTRACAM study of the fast optical quasi-periodic oscillations in the polar V834 CentauriQuasi-periodic oscillations (QPOs) of a few seconds have been detected in some polars, the synchronised subclass of cataclysmic systems containing a strongly magnetised white dwarf which accretes matter from a red dwarf companion. The QPOs are thought to be related to instabilities of a shock formed in the accretion column, close to the white dwarfMouchet, M. et al.
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32017 -
A refined analysis of the low-mass eclipsing binary system T-Cyg1-12664Context. The observational mass-radius relation of main sequence stars with masses between 0.3 and 1.0 M⊙ reveals deviations between the stellar radii predicted by models and the observed radii of stars in detached binaries. Aims: We generate an accurate physical model of the low-mass eclipsing binary T-Cyg1-12664 in the Kepler mission field toIglesias-Marzoa, R. et al.
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32017 -
PTF1 J082340.04+081936.5: A Hot Subdwarf B Star with a Low-mass White Dwarf Companion in an 87-minute OrbitWe present the discovery of the hot subdwarf B star (sdB) binary PTF1 J082340.04+081936.5. The system has an orbital period of {P}{orb} = 87.49668(1) minutes (0.060761584(10) days), making it the second-most compact sdB binary known. The light curve shows ellipsoidal variations. Under the assumption that the sdB primary is synchronized with theKupfer, T. et al.
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22017 -
Synchrotron emission from the blazar PG 1553+113. An analysis of its flux and polarization variabilityIn 2015 July 29-September 1, the satellite XMM-Newton pointed at the BL Lac object PG 1553+133 six times, collecting data for 218 h. During one of these epochs, simultaneous observations by the Swift satellite were requested to compare the results of the X-ray and optical-UV instruments. Optical, near-infrared and radio monitoring was carried outRaiteri, C. M. et al.
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42017 -
A millisecond pulsar candidate in a 21-h orbit: 3FGL J0212.1+5320We present the discovery of a variable optical counterpart to the unidentified gamma-ray source 3FGL J0212.1+5320 and argue that this is a new compact binary millisecond pulsar (MSP) candidate. We show 3FGL J0212.1+5320 hosts a semidetached binary with a 0.869 55 ± 0.000 15 d orbital period and an F6-type companion star at an estimated distance ofLinares, M. et al.
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32017
