Szilard Csizmadia's research while affiliated with German Aerospace Center (DLR) and other places

Publications (19)

Conference Paper
We study the inner structure of exoplanets by determining the Love numbers kn and hn, which describe the susceptibility of their shape to change in response to a tidal and rotational potential. The second degree Love number k2 is highly sensitive to the thickness of the interior layers and rheology of the planet and it is proportional to the concen...
Article
Full-text available
We report the discovery and characterisation of a pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 (TIC 79748331), initially detected in TESS photometry. To characterise the system, we performed and retrieved CHEOPS, TESS, and ground-based photometry, HARPS high-resolution spectroscopy, and Gemini speckle imaging. We characterise the hos...
Preprint
Full-text available
We report the discovery and characterisation of a pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 (TIC 79748331), initially detected in TESS photometry. To characterise the system, we performed and retrieved CHEOPS, TESS, and ground-based photometry, HARPS high-resolution spectroscopy, and Gemini speckle imaging. We characterise the hos...
Preprint
CoRoT was the first space mission dedicated to exoplanet detection. Operational between 2007 and 2012, this mission discovered 37 transiting planets, including CoRoT-7b, the first terrestrial exoplanet with a measured size. The precision of the published transit ephemeris of most of these planets has been limited by the relative short durations of...
Article
A nearby iron-rich sub-Earth planet The mass and radius of an exoplanet determine its mean density, which provides information about the possible interior structure. Lam et al . have identified a planet on a 7.7-hour orbit around a nearby red dwarf star. The authors determined the planet’s radius from the transit, then used radial velocity observat...
Article
Ultrashort-period (USP) exoplanets have orbital periods shorter than 1 day. Precise masses and radii of USP exoplanets could provide constraints on their unknown formation and evolution processes. We report the detection and characterization of the USP planet GJ 367b using high-precision photometry and radial velocity observations. GJ 367b orbits a...
Preprint
Ultra-short-period (USP) exoplanets have orbital periods shorter than one day. Precise masses and radii of USPs could provide constraints on their unknown formation and evolution processes. We report the detection and characterization of the USP planet GJ 367b using high precision photometry and radial velocity observations. GJ 367b orbits a bright...
Article
Full-text available
CoRoT was the first space mission dedicated to exoplanet detection. Operational between 2007 and 2012, this mission discovered 37 transiting planets, including CoRoT-7b, the first terrestrial exoplanet with a measured size. The precision of the published transit ephemeris of most of these planets has been limited by the relative short durations of...
Conference Paper
The Nancy Grace Roman Space Telescope, to be launched in 2025, will directly image exoplanets in reflected starlight for the first time. This observing technique will enable the study of a population of exoplanets whose atmospheres cannot be characterized with current techniques. Previous works have analysed the possible science outcome of reflecte...
Article
Full-text available
We report on precise Doppler measurements of L231-32 (TOI-270), a nearby M dwarf (d = 22 pc, M⋆ = 0.39 M⊙, R⋆ = 0.38 R⊙), which hosts three transiting planets that were recently discovered using data from the Transiting Exoplanet Survey Satellite (TESS). The three planets are 1.2, 2.4, and 2.1 times the size of Earth and have orbital periods of 3.4...
Preprint
The theory of remote sensing shows that observing a planet at multiple phase angles ($\alpha$) is a powerful strategy to characterize its atmosphere. Here, we analyse how the information contained in reflected-starlight spectra of exoplanets depends on the phase angle, and the potential of multi-phase measurements to better constrain the atmospheri...
Article
We present the discovery of NGTS-19b, a high-mass transiting brown dwarf discovered by the Next Generation Transit Survey. We investigate the system using follow-up photometry from the South African Astronomical Observatory, as well as sector 11 Transiting Exoplanet Survey Satellite data, in combination with radial velocity measurements from the CO...
Preprint
Full-text available
We present 17 transit light curves of seven known warm-Jupiters observed with the CHaracterising ExOPlanet Satellite (CHEOPS). The light curves have been collected as part of the CHEOPS Guaranteed Time Observation (GTO) program that searches for transit-timing variation (TTV) of warm-Jupiters induced by a possible external perturber to shed light o...
Article
Full-text available
We present the discovery of NGTS-19b a high mass transiting brown dwarf discovered by the Next Generation Transit Survey (NGTS). We investigate the system using follow up photometry from the South African Astronomical Observatory, as well as sector 11 TESS data, in combination with radial velocity measurements from the CORALIE spectrograph to preci...
Preprint
We present the discovery of NGTS-19b, a high mass transiting brown dwarf discovered by the Next Generation Transit Survey (NGTS). We investigate the system using follow up photometry from the South African Astronomical Observatory, as well as sector 11 TESS data, in combination with radial velocity measurements from the CORALIE spectrograph to prec...
Conference Paper
Directly imaging exoplanets in reflected starlight will enable the atmospheric characterization of long-period exoplanets, which are not accessible to current techniques. The launch of the Roman Space Telescope (planned in the mid-2020s) will pave the way for a future generation of telescopes both in space and on the ground (LUVOIR, HabEx, ELTs...)...
Conference Paper
The Roman Space Telescope will be the first mission to analyse exoplanets by directly imaging them in reflected starlight. This technique will enable the atmospheric characterization of long-period planets which cannot be studied by current facilities. In this work, we analysed the exoplanet detection yield of the Roman Space Telescope's coronagrap...
Conference Paper
We report on the spectroscopic follow-up of TESS planetary candidates with a network of 2-3 meter telescopes located in Ondrejov, CZ, Tautenburg, DE, McDonald observatory, US and SMARTS telescope, CL, which use spectrographs with high resolving power. We coordinate our observing campaigns within the KESPRINT consortium and we significantly contribu...
Conference Paper
Hot Jupiters are a class of exoplanets, orbiting very close to their host stars. What is unusual about them is that gas planets are predicted to form beyond the snow line, a few astronomical units from their stars in the case of solar-like stars. Migration mechanisms like disc-driven migration or migration via dynamical processes can explain these...

Citations

... As discussed in previous analyses (e.g., Deline et al. 2022;Hooton et al. 2022;Wilson et al. 2022), CHEOPS photometry is affected by variable contamination from other stars in the field of view. The variability of this contamination is due to the fact that the Point Spread Function (PSF) of the stars is not circular and the overlap with the target PSF depends on the roll angle of the telescope (Benz et al. 2021). ...
... Most of the USP small planets (for example, Kepler-78 b 15 and CoRoT-7 b 16 ) have a bulk composition comprising ~30% iron and ~70% silicates 17 , similar to Earth. Although TOI-500 b falls in this same interval of compositions, it stands out of the crowd because, after GJ 367 b 18 , it is the leftmost planet in the plot, one of the smallest and lightest of its type. ...
... In future research, this can be done by adding more data points, for instance, using ground-or space-based photometry, which will allow to measure the mass of this object. Along the same line, many published CoRoT planets have recently been re-observed by TESS, allowing to optimise the transit periods and ephemeris (Klagyivik et al. 2021 ). The possibility to find a planetary system together with the rarity of such inflated GPs orbiting stars with sub-solar metallicity, makes the detection of CoRoT-35b a rare benchmark object for the planet formation of such stars (e.g. ...
... To this end, with planetary speeds of the order of 10 4 m s −1 , constraints of the the order of 10 −6 could be obtained. However, the exploration of exoplanetary systems brings about features that are unexpected, based on the knowledge of the solar system; for instance, there are planets moving at very high speed, of the order of 10 5 m s −1 (see Lam et al. [41]). A combination of these peculiar planets and improvements in detection techniques could lead to even tighter constraints on the SME coefficients. ...
... GJ 3929b is an Earth-sized exoplanet, placing it below the radius gap for M dwarfs (Van Eylen et al. 2021;Petigura et al. 2022). Our mass and radius estimates allow us to constrain GJ 3929b's bulk density and confirm its consistency with a composition slightly denser than Earth (Figure 9). ...
... Through an adaptive optics imaging survey, Metchev et al. (2009) found that there were more BDs at wide orbits than BDs in the BD desert. Recently, more and more BDs have been found to reside in this desert (e.g., Carmichael et al. 2019Carmichael et al. , 2020Persson et al. 2019;Acton et al. 2021). As suggested by Shahaf & Mazeh (2019), the characterization of the shape of the BD desert in a period-mass diagram by means of a large sample of circumstellar BDs can improve our understanding of its origin. ...