Franz-Josef Hambsch
A5052026679- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Nuclear Physics and Applications
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Nuclear reactor physics and engineering
- High-pressure geophysics and materials
- Pulsars and Gravitational Waves Research
- Nuclear physics research studies
- Laser-Plasma Interactions and Diagnostics
- Nuclear Materials and Properties
- Atomic and Subatomic Physics Research
- Radiation Detection and Scintillator Technologies
- Astrophysics and Cosmic Phenomena
- Geophysics and Gravity Measurements
- History and Developments in Astronomy
- Particle Accelerators and Free-Electron Lasers
- Calibration and Measurement Techniques
- Mechanics and Biomechanics Studies
- Graphite, nuclear technology, radiation studies
- X-ray Spectroscopy and Fluorescence Analysis
- Atmospheric Ozone and Climate
Bundesdeutsche Arbeitsgemeinschaft für Veränderliche Sterne
2016-2025
American Association of Variable Star Observers
2014-2025
Stichting tot Steun VCVGZ
2023-2025
Vlaamse Vereniging voor Obstetrie en Gynaecolo
2014-2024
Joint Research Center
2002-2020
Belgian Nuclear Research Centre
2013-2020
Uppsala University
2020
European Commission
2012-2019
Royal Observatory of Belgium
2019
Atacama Large Millimeter Submillimeter Array
2017
We report the results of a three-year-long dedicated monitoring campaign restless luminous blue variable (LBV) in NGC 7259. The object, named SN 2009ip, was observed photometrically and spectroscopically optical near-infrared domains. monitored number erupting episodes past few years, increased density our observations during eruptive episodes. In this paper, we present full historical data set from 2009 to 2012 with multi-wavelength dense coverage two high-luminosity events between August...
The substellar companion HD206893b has recently been discovered by direct imaging of its disc-bearing host star with the SPHERE instrument. We investigate atypical properties companion, which reddest near-infrared colours among all known objects, either orbiting a or isolated, and we provide comprehensive characterisation star-disc-companion system. conducted follow-up adaptive optics spectro-imaging SPHERE, multiinstrument star. obtain R=30 spectrum from 0.95 to 1.64 micron additional...
ABSTRACT We report the discovery of closest known black hole candidate as a binary companion to V723 Mon. Mon is nearby ($d\sim 460\, \rm pc$), bright (V ≃ 8.3 mag), evolved (Teff, giant 4440 K, and Lgiant 173 L⊙) red in high mass function, f(M) = 1.72 ± 0.01 M⊙, nearly circular (P 59.9 d, e 0). variable star, previously classified an eclipsing binary, but its All-Sky Automated Survey, Kilodegree Extremely Little Telescope, Transiting Exoplanet Survey Satellite light curves are those edge-on...
The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear technologies - 235,238U, 239Pu, 56Fe, 16O and 1H with the aim of improving accuracy data resolving previous discrepancies our understanding. This multi-laboratory pilot project, coordinated via OECD/NEA Working Party Evaluation Cooperation (WPEC) Subgroup 40 support also from IAEA, motivated experimental theoretical work led to suites new evaluated libraries accurately...
Proxima could host a planet on ∼5-year orbit, which Gaia can confirm in the near future providing its exact mass.
Context. Large surveys with new-generation high-contrast imaging instruments are needed to derive the frequency and properties of exoplanet populations separations from ~5 300 au. A careful assessment stellar is crucial for a proper understanding when, where, how frequently planets form, they evolve. The sensitivity detection limits age makes this key parameter direct surveys. Aims. We describe SpHere INfrared survey Exoplanets (SHINE), largest planet-search campaign initiated at VLT in 2015...
Abstract Continued from Kato et al. (2009, PASJ, 61, S395), we collected the times of superhump maxima for 68 SU UMa-type dwarf novae, mainly observed during 2009–2010 season. The newly obtained data confirmed basic findings reported in (ibid.): presence stages A–C and predominance positive period derivatives stage B systems with periods shorter than 0.07 d. There was a systematic difference longer 0.075 d between this study (ibid.). We suggest that possibly caused by relative lack...
We summarize the results of a 20-yr campaign to study light curves BK Lyn, nova-like star strangely located below 2 3 h orbital-period gap in family cataclysmic variables (CVs). Two apparent superhumps dominate nightly curves, with periods 4.6 per cent longer, and 3.0 shorter, than orbital period. The first appears be associated star's brighter states (V ∼ 14), while second present throughout becomes very dominant low state 15.7). It is plausible that these arise, respectively, from prograde...
Continuing the project described by Kato et al. (2009, arXiv:0905.1757), we studied 86 SU UMa-type dwarf novae. We confirmed general trends such as relation between period derivatives and orbital periods. There are some systems showing positive despite long observed 2011 outburst of WZ Sge-type nova BW Scl, recorded an O-C diagram similar to those previously known The OT J184228.1+483742 showed unusual pattern double outbursts composed with early superhumps one ordinary superhumps. propose...
Small low-mass stars are favourable targets for the detection of rocky habitable planets. In particular, planetary systems in solar neighbourhood interesting and suitable precise characterisation. The Red Dots campaigns seek to discover planets orbiting nearby stars. 2018 campaign targeted GJ 1061, which is 20$^{\rm th}$ nearest star Sun. For three consecutive months we obtained nightly, high-precision radial velocity measurements with HARPS spectrograph. We analysed these data together...
Abstract We present an analysis of ground-based and JWST observations SN 2022pul, a peculiar “03fg-like” (or “super-Chandrasekhar”) Type Ia supernova (SN Ia), in the nebular phase at 338 days postexplosion. Our combined spectrum continuously covers 0.4–14 μ m includes first mid-infrared 03fg-like Ia. Compared to normal 2021aefx, 2022pul exhibits lower mean ionization state, asymmetric emission-line profiles, stronger emission from intermediate-mass elements (IMEs) argon calcium, weaker...
Abstract Continuing the project described by Kato et al. (2009, PASJ, 61, S395), we collected times of superhump maxima for 51 SU UMa-type dwarf novae, mainly observed during 2010–2011 season. Although most new data systems with short periods basically confirmed findings (ibid.) and (2010, 62, 1525), long-period system GX Cas showed an exceptionally large positive-period derivative. An analysis public Kepler V344 Lyr V1504 Cyg yielded less-striking stage transitions. In Lyr, there was a...
Continuing the project described by Kato et al. (2009, arXiv:0905.1757), we collected times of superhump maxima for 102 SU UMa-type dwarf novae observed mainly during 2014-2015 season and characterized these objects. Our has greatly improved statistics distribution orbital periods, which is a good approximation cataclysmic variables at terminal evolutionary stage, confirmed presence period minimum 0.053 d spike just above this period. The number density monotonically decreased toward longer...
Continuing the project described by Kato et al. (2009a, arXiv:0905.1757), we collected times of superhump maxima for SU UMa-type dwarf novae mainly observed during 2012-2013 season. We found three objects (V444 Peg, CSS J203937 and MASTER J212624) having strongly positive period derivatives despite long orbital (Porb). By using growing stage (stage A) superhumps, obtained mass ratios six objects. characterized nine new WZ Sge-type novae. made a pilot survey decline rate slowly fading part...
Nebular-phase observations of peculiar Type Ia supernovae (SNe Ia) provide important constraints on progenitor scenarios and explosion dynamics for both these rare SNe the more common, cosmologically useful Ia. We present from an extensive ground-based space-based follow-up campaign to characterize SN 2022pul, a "super-Chandrasekhar" mass (alternatively "03fg-like" SN), before peak brightness well into nebular phase across optical mid-infrared (MIR) wavelengths. The early rise light curve is...
Low-mass members of young stellar associations exhibit a wide spread rotation periods. Such originates from distributions masses and initial However, multiplicity can also play significant role. We investigate the role played by physical companions in shortening primordial disc lifetime. have compiled most extensive list low-mass 25-Myr beta Pictoris association. measured periods about all used updated UVWXYZ components to assess their membership. built period distribution distinguishing...
Abstract Continuing the project described by Kato et al. (2009, PASJ, 61, S395), we collected times of superhump maxima for 128 SU UMa-type dwarf novae observed mainly during 2015–2016 season and characterized these objects. The data have improved distribution orbital periods, relation between period variation superhumps, variations rebrightening type in WZ Sge-type Coupled with new measurements mass ratios using growing stages now a clearer statistically greatly evolutionary path near...
We report the discovery in $TESS$ Sectors 3 and 4 of a compact triply eclipsing triple star system. TIC 209409435 is previously unknown binary with period 5.717 days, presence third an outer eccentric orbit 121.872 day was found from two sets third-body eclipses eclipse timing variations. The latter exhibit signatures strong 3rd-body perturbations. After discovery, we obtained follow-up ground-based photometric observations several as well another eclipses. carried out comprehensive...
Abstract The Transiting Exoplanet Survey Satellite (TESS) space telescope is collecting continuous, high-precision optical photometry of stars throughout the sky, including thousands RR Lyrae stars. In this paper, we present results for an initial sample 118 nearby observed in TESS Sectors 1 and 2. We use differential image to generate light curves analyze their mode content modulation properties. combine accurate light-curve parameters from with parallax color information Gaia mission...
Abstract T CrB is a symbiotic recurrent nova that last erupted in 1946. Given its recurrence timescale of approximately 80 years, the next outburst eagerly anticipated by astronomical community. In this work, we analyse optical light curves CrB, comparing recent photometric evolution with historical data to evaluate potential predictive indicators eruptions. Although ‘super-active’ phases preceding both 1946 and eruptions are strikingly similar, subsequent behaviour differs. We find decline...
We report photometric detections of orbital and superorbital signals, negative sidebands, in the light curves nova-like cataclysmic variables AQ Mensae IM Eridani. The frequencies orbital, sideband signals are 7.0686 (3), 0.263 (3) 7.332 cycles d−1 (c d−1) Mensae, 6.870 (1), 0.354 (7) 7.226 (1) c also find a spectroscopic frequency Eridani 6.86649 (2) d−1. These observations can be reproduced by invoking an accretion disc that is tilted with respect to plane. This model works well for X-ray...
We intended to compile the most complete catalog of bona fide members and candidate beta Pictoris association, measure their rotation periods basic properties from our own observations, public archives, exploring literature. carried out a multi-observatories campaign get photometric time series collected all archived data for stars in catalog. Each was analyzed with Lomb-Scargle CLEAN periodograms search stellar periods. complemented measured rotational detailed information on multiplicity,...
We report extensive 3-yr multiwavelength observations of the WZ Sge-type dwarf nova SSS J122221.7−311525 during its unusual double superoutburst, following decline and in quiescence. The second segment superoutburst had a long duration 33 d very gentle with rate 0.02 mag d−1, it displayed an extended post-outburst lasting at least 500 d. Simultaneously start rapid fading from plateau, system showed appearance strong near-infrared excess resulting red colours, which reached extreme values (B...