A5071882540- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- High-pressure geophysics and materials
- Pulsars and Gravitational Waves Research
- Space Exploration and Technology
- Oceanographic and Atmospheric Processes
- Scientific Research and Discoveries
- Adaptive optics and wavefront sensing
Institute of Astronomy
2023-2024
KU Leuven
2023-2024
University of Valparaíso
2019-2023
European Southern Observatory
2020-2023
Nicolaus Copernicus University
2023
Valparaiso University
2021
Osservatorio Astrofisico di Torino
2019
Ankara University
2017
We report the discovery of 74 new pulsating DA white dwarf stars, or ZZ Cetis, from data obtained by Transiting Exoplanet Survey Satellite (TESS) mission, Sectors 1 to 39, corresponding first 3 cycles. This includes objects Southern Hemisphere (Sectors 1-13 and 27-39) Northern 14-26), observed with 120 s- 20 s-cadence. Our sample likely 13 low-mass one extremely candidate, considering mass determinations fitting Gaia magnitudes parallax. In addition, we present follow-up time series...
We report on the confirmation and follow-up characterization of two long-period transiting substellar companions low-eccentricity orbits around TIC 4672985 TOI-2529, whose transit events were detected by TESS space mission. Ground-based photometric spectroscopic from different facilities, confirmed nature b , a massive gas giant in transition between super-Jupiters brown dwarfs mass regime. From joint analysis we derived following orbital parameters: P = 69.0480 −0.0005 +0.0004 d, M p 12.74...
With the PLAnetary Transits and Oscillation of stars (PLATO) space mission set for launch in December 2026 by European Space Agency (ESA), a new photometric legacy future scientific discoveries await community. By exploring topics outside core science program, PLATO complementary program (PLATO-CS) provides unique opportunity to maximise yield mission. In this work, we investigate PLATO’s potential observing pulsating across Hertzsprung--Russell diagram (HRD). This search is distinct from...
The discovery of pulsations in ultra-massive white dwarfs can help to probe their interiors and unveil core composition crystallized mass fraction through asteroseismic techniques. To date, the richest pulsating dwarf known is BPM 37093 with 8 modes detected, for which detailed analysis has been performed past. In this work, we report 19 pulsation star WD~J0135+5722, making it hydrogen-atmosphere ultramassive date. %In a hydrogen-rich observed Gran Telescopio Canarias. This object exhibits...
Abstract The discovery of pulsations in ultramassive (UM) white dwarfs (WDs) can help to probe their interiors and unveil core composition crystallized mass fraction through asteroseismic techniques. To date, the richest pulsating UM WD known is BPM 37093 with 8 modes detected, for which detailed analysis has been performed past. In this work, we report 19 pulsation star J0135+5722, making it hydrogen-atmosphere date. This object exhibits multiperiodic luminosity variations periods ranging...
We present the first volume-limited sample of spectroscopically confirmed hot subluminous stars out to 500 pc, defined using accurate parallax measurements from Gaia space mission data release 3 (DR3). The comprises a total 397 members, with 305 (~77%) identified as subdwarf stars, including 83 newly discovered systems. Of these, we observe that 178 (~58%) are hydrogen-rich sdBs, 65 sdOBs (~21%), 32 sdOs (~11%), and 30 He-sdO/Bs (~10%). Among them, 48 (~16%) exhibit an infrared excess in...
We present the discovery and asteroseismic analysis of a new g-mode hot B subdwarf (sdB) pulsator, EC 21494-7018 (TIC 278659026), monitored in TESS first sector using 120-second cadence. The light curve reveals that is sdB pulsator counting up to 20 frequencies associated with independent g-modes. seismic singles out an optimal model solution full agreement measurements provided by spectroscopy (atmospheric parameters derived from atmospheres) astrometry (distance evaluated Gaia DR2...
Pulsation frequencies reveal the interior structures of white dwarf stars, shedding light on properties these compact objects that represent final evolutionary stage most stars. Two-minute cadence photometry from TESS will record pulsation signatures bright dwarfs over entire sky. We aim to demonstrate sensitivity data measuring pulsations helium-atmosphere in DBV instability strip, and what asteroseismic analysis measurements can constrain about their stellar structures. present a case...
Context. The recent arrival of continuous photometric observations unprecedented quality from space missions has strongly promoted the study pulsating stars and caused great interest in stellar astrophysics community. In particular case white dwarfs, TESS mission is taking asteroseismology these compact to a higher level, emulating or even surpassing performance its predecessor, Kepler mission. Aims. We present detailed asteroseismological analysis six GW Vir that includes collected by...
We report on the spectroscopic confirmation of 68 new bright ( G = 13.5–17.2 mag) and blue (pre-)white dwarfs (WDs). This finding has allowed us to almost double number hottest T eff ≥ 60 kK) known WDs brighter than 16 mag. increased ultra-high excitation (UHE) by 20%, found one unambiguous close binary system consisting DA WD with an irradiated low-mass companion, DAO, DOA that are likely in their transformation phase becoming pure WDs, rare, naked O(H) star, two DAO possibly excess 100 kK,...
Context. We present our findings on 18 formerly known ZZ Ceti stars observed by the TESS space telescope in 120s cadence mode during survey observation of southern ecliptic hemisphere. Aims. focus frequency analysis space-based observations, comparing results with previous ground-based measurements. The frequencies detected observations can serve as inputs for future asteroseismic analyses. Methods. performed standard pre-whitening data sets to derive possible pulsation different targets. In...
ABSTRACT G 29 − 38 (TIC 422526868) is one of the brightest (V = 13.1) and closest (d 17.51 pc) pulsating white dwarfs with a hydrogen-rich atmosphere (DAV/ZZ Ceti class). It was observed by TESS spacecraft in sectors 42 56. The polluted heavy elements that are expected to sink out visible layers on short time-scales. photometric data set spans ∼51 d total, from this, we identified 56 significant pulsation frequencies, include rotational frequency multiplets. In addition, 30 combination...
Hot subdwarf B (sdB) stars are evolved, subluminous, helium-burning that most likely form when red giant loose their hydrogen envelope via interactions with close companions. They play an important role in our understanding of binary evolution, stellar atmospheres, and interiors. Only a small fraction the sdB population is known to exhibit pulsations. Pulsating sdBs have typically been discovered serendipitously various photometric surveys because specific selection criteria for sample...
We report on the detection of pulsations three pulsating subdwarf B stars observed by TESS satellite and our results mode identification in these based an asymptotic period relation. SB 459 (TIC 067584818), 815 169285097) PG 0342+026 457168745) have been monitored during single sectors resulting 27 days coverage. These datasets allowed for detecting, each star, a few tens frequencies, which we interpreted as stellar oscillations. found no multiplets, though partially constrained geometry...
We present photometric and spectroscopic analyses of gravity (g-mode) long-period pulsating hot subdwarf B (sdB) stars. perform a detailed asteroseismic analysis five sdB stars observed with {\it TESS} aiming at the global comparison observations model predictions based on our stellar evolution computations coupled adiabatic pulsation computations. apply standard seismic tools for mode identification, including asymptotic period spacings rotational frequency multiplets. calculate mean...
Context. The possible existence of warm ( T eff ∼ 19 000 K) pulsating DA white dwarf (WD) stars, hotter than ZZ Ceti was predicted in theoretical studies more 30 yr ago. These reported the occurrence g -mode pulsational instabilities due to κ mechanism acting partial ionization zone He below H envelope models WDs with very thin envelopes M / ⋆ ≲ 10 −10 ). However, date, no WD has been discovered, despite varied and observational evidence suggesting that a fraction should be formed range low...
HD4539 (alias PG0044+097 or EPIC220641886) is a bright (V=10.2) long-period V1093 Her-type subdwarf B (sdB) pulsating star that was observed by the Kepler spacecraft in its secondary (K2) mission. We use K2 light curve (78.7 days) to extract 169 pulsation frequencies, 124 with robust detection. Most of these frequencies are found low-frequency region typical gravity (g-)modes, but some higher corresponding pressure (p-)modes also detected. Therefore hybrid pulsator and both deep surface...
Context. Significant advances have been achieved through the latest improvements in photometric observations accomplished by recent space missions, which substantially boost study of pulsating stars via asteroseismology. The TESS mission has already proven to be particular relevance for white dwarf and pre-white stars. Aims. We report a detailed asteroseismic analysis PG 1159 star NGC 246 (TIC 3905338), is central planetary nebula 246, based on high-precision data gathered mission. Methods....
The main science aim of the BlackGEM array is to detect optical counterparts gravitational wave mergers. Additionally, will perform a set synoptic surveys Local Universe transients and short time-scale variability in stars binaries, as well six-filter all-sky survey down ~22nd mag. Phase-I consists three wide-field unit telescopes. Each uses an f/5.5 modified Dall-Kirkham (Harmer-Wynne) design with triplet corrector lens, 65cm primary mirror, coupled 110Mpix CCD detector, that provides...
A central challenge in the field of stellar astrophysics lies accurately determining mass stars, particularly when dealing with isolated ones. However, for pulsating white dwarf task becomes more tractable due to availability multiple approaches such as spectroscopy, asteroseismology, astrometry, and photometry, each providing valuable insights into properties stars. Numerous asteroseismological studies dwarfs have been published, focusing on using pulsational spectra comparing it...
Abstract The main science aim of the BlackGEM array is to detect optical counterparts gravitational wave mergers. Additionally, will perform a set synoptic surveys Local Universe transients and short timescale variability in stars binaries, as well six-filter all-sky survey down ∼22nd mag. Phase-I consists three wide-field unit telescopes. Each uses an f /5.5 modified Dall-Kirkham (Harmer-Wynne) design with triplet corrector lens, 65 cm primary mirror, coupled 110Mpix CCD detector, that...
KIC 10001893 is a V1093 Her type pulsating subdwarf-B star, which was observed extensively by the Kepler spacecraft. It part of survey searching for compact pulsators in field view. An amplitude spectrum star demonstrates rich content g-modes between 102 and 496 {\mu}Hz as well few p-modes above 2000 {\mu}Hz. In total, we found 110 frequencies. The g-mode region contains 104 frequencies, while p-mode just six, altogether indicating hybrid nature 10001893. main goal our analysis to identify...
ABSTRACT Transiting Exoplanet Survey Satellite (TESS) observations show CD−28° 1974 to be a gravity(g)-mode-dominated hybrid pulsating subdwarf B (sdBV) star. It shows 13 secure periods that form an ℓ = 1 asymptotic sequence near the typical period spacing. Extraordinarily, these lie between 1500 and 3300 s, whereas $\ell 1\, g$ modes in sdBV stars occur 10 000 s. This indicates structure somewhat different from stars. has visually close F/G main-sequence companion 1.33 arcsec away, which...
Context. The Transiting Exoplanet Survey Satellite (TESS) mission is revolutionizing the blossoming area of asteroseismology, particularly pulsating white dwarfs and pre-white dwarfs, thus continuing impulse its predecessor, Kepler mission. Aims. In this paper, we present observations from extended TESS in both 120 s short-cadence 20 ultra-short-cadence mode two dwarf stars showing hydrogen deficiency. We identify them as new GW Vir stars, TIC 333432673 095332541. apply tools...