Stephen M. Brincat
A5089782620- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- Astronomy and Astrophysical Research
- Planetary Science and Exploration
- High-pressure geophysics and materials
- Astrophysics and Star Formation Studies
- Isotope Analysis in Ecology
- Pulsars and Gravitational Waves Research
- Geophysics and Gravity Measurements
- Space Exploration and Technology
- Laser-Plasma Interactions and Diagnostics
- Solar and Space Plasma Dynamics
- Calibration and Measurement Techniques
- Global Health Care Issues
- Astrophysics and Cosmic Phenomena
- Geophysics and Sensor Technology
- Atmospheric Ozone and Climate
- Historical Studies on Spain
- Space Satellite Systems and Control
- Advanced Data Storage Technologies
- Historical and Architectural Studies
- Marine and coastal ecosystems
American Association of Variable Star Observers
2018-2023
University of Malta
2022
Abstract The ExoClock project is an inclusive, integrated, and interactive platform that was developed to monitor the ephemerides of Ariel targets increase mission efficiency. makes best use all available resources, i.e., observations from ground telescopes, midtime values literature, finally, space instruments. Currently, network includes 280 participants with telescopes capable observing 85% currently known candidate targets. This work results ∼1600 obtained up 2020 December 31 network....
Abstract The ExoClock project has been created to increase the efficiency of Ariel mission. It will achieve this by continuously monitoring and updating ephemerides candidates, in order produce a consistent catalog reliable precise ephemerides. This work presents homogenous updated for 450 planets, generated integration ∼18,000 data points from multiple sources. These sources include observations ground-based telescopes (the network Exoplanet Transit Database), midtime values literature,...
Abstract We present a photometric detection of the first brightness dips unique variable star KIC 8462852 since end Kepler space mission in 2013 May. Our regular surveillance started 2015 October, and sequence dipping began 2017 May continuing on through 2017, when was no longer visible from Earth. distinguish four main 1%–2.5% dips, named “ Elsie ,” Celeste Skara Brae Angkor which persist timescales several days to weeks. results so far are as follows: (i) there apparent changes stellar...
Dwarf novae are a crucial astrophysical laboratory for probing the nature of accretion, binary mass transfer, and evolution -- yet their diverse observational characteristics continue to challenge our theoretical understanding. We here present discovery of, subsequent observing campaign on GOTO065054+593624 (hereafter GOTO0650), dwarf nova WZ Sge type, discovered in real-time by citizen scientists via Kilonova Seekers science project. An extensive dataset charts photometric spectroscopic...
We report the analysis of a planetary microlensing event AT2021uey. The was observed outside Galactic bulge and alerted both space-( Gaia ) ground-based (ZTF ASAS-SN) surveys. From data, we find that lens system is located at distance ∼1 kpc comprises an M-dwarf host star about half solar mass, orbited by Jupiter-like planet beyond snowline. source could be metal-poor giant in halo according to spectral analyses modelling. Hence, AT2021uey unique example binary-lens offered disc-halo...
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 present optical photometry of six intermediate polars that exhibit transitions to a low-flux state. For four these systems, DW Cnc, V515 And, V1223 Sgr and RX J2133.7+5107, we are able perform timing analysis in out the low states. find that, for Cnc dominant periodicities light curves change as flux decreases, indicating sources' accretion properties they transition variability is almost completely quenched at lowest flux, but do not evidence changing geometry. temporal state, see period...
Abstract We present our optical photometric observations of the 2022 eruption recurrent nova U Scorpii (U Sco) using 49152 data points over 70 d following peak. have also analyzed its soft X-ray (0.3–1 keV) light curve by Neil Gehrels Swift Observatory. During eruption, plateau stage started 13.8–15.0 and ended 23.8–25.0 after The 14.6–15.3 38.7–39.5 Both stages later had shorter durations, peaked earlier was less luminous compared to those during Sco 2010 eruption. These suggest that there...
Results from the TESS mission showed that previous studies strngly underestimated number of slow rotators, revealing importance studying those asteroids. For most slowly rotating asteroids (P > 12), no spin and shape model is available because observation selection effects. This hampers determination their thermal parameters accurate sizes. We continue our campaign in minimising effects among main belt Our targets are rotators with low light-curve amplitudes. The goal to provide scaled...
Abstract We present optical photometry of superoutbursts that occurred in 2016 two WZ Sge-type dwarf novae (DNe), ASASSN-16dt and ASASSN-16hg. Their light curves showed a dip brightness between the first plateau stage with no ordinary superhumps (or early superhumps) second superhumps. find is produced by slow evolution 3 : 1 resonance tidal instability it would likely be observed low mass-ratio objects. An estimated mass ratio (q ≡ M2/M1) from period developing (stage A) [0.06420(3) d] was...
We report photometric and spectroscopic observations analysis of the 2019 superoutburst TCP J21040470+4631129. This object showed a 9-mag with early superhumps ordinary superhumps, which are features WZ Sge-type dwarf novae. Five rebrightenings were observed after main superoutburst. The spectra during post-superoutburst stage Balmer, He I possible sodium doublet features. mass ratio is derived as 0.0880(9) from period superhump. During third fifth rebrightenings, growing superoutbursts...
Abstract New results on the behavior of double-mode RR Lyrae V338 Boo are presented. The Transiting Exoplanet Survey Satellite (TESS) observed this star again in 2022, and an observing campaign American Association Variable Star Observers (AAVSO) was completed after TESS observations as a follow-up. We find that first overtone pulsation mode completely disappears during window. This reappears at end observations, AAVSO shows months followed, not only present but dominant pulsation. star,...
Continuing the project described by Kato et al. (2009, arXiv:0905.1757), we collected times of superhump maxima for 127 SU UMa-type dwarf novae observed mainly during 2016--2017 season and characterized these objects. We provide updated statistics relation between orbital period variation superhumps, variations rebrightening type in WZ Sge-type obtained minimum 0.05290(2)d confirmed presence gap above ~0.09d. note that four objects (NY Her, 1RXS J161659.5+620014, CRTS J033349.8-282244 SDSS...
PDS 110 is a young disk-hosting star in the Orion OB1A association. Two dimming events of similar depth and duration were seen 2008 (WASP) 2011 (KELT), consistent with an object closed periodic orbit. In this paper we present data from ground-based observing campaign designed to measure both photometrically spectroscopically during time predicted eclipse September 2017. Despite high-quality photometry, did not occur, although coherent structure suggesting variable amounts stellar flux or...
Continuing the project described by Kato et al. (2009, PASJ, 61, S395, arXiv/0905.1757), we collected times of superhump maxima for 102 SU UMa-type dwarf novae observed mainly during 2017 season and characterized these objects. WZ Sge-type stars identified in this study are PT And, ASASSN-17ei, ASASSN-17el, ASASSN-17es, ASASSN-17fn, ASASSN-17fz, ASASSN-17hw, ASASSN-17kd, ASASSN-17la, PNV J20205397+2508145 TCP J00332502-3518565. We obtained new mass ratios 7 objects using growing superhumps...
Abstract The intermediate polar FO Aquarii (FO Aqr) experienced its first reported low-accretion states in 2016, 2017, and 2018, and, using newly available photographic plates, we identify prediscovery low 1965, 1966, 1974. primary focus of our analysis, however, is an extensive set time-series photometry obtained between 2002 with particularly intensive coverage the 2016–2018 states. After computing updated spin ephemeris for white dwarf (WD), show that period began to increase 2014 after...
We present spectroscopic and photometric observations of 17 dwarf-nova superoutbursts obtained by KOOLS-IFU mounted on the 3.8 m telescope Seimei at Okayama Observatory Kyoto University through VSNET collaboration. Our for six outbursts were performed within 1 d from their optical peak. 11 objects (TCP J00590972+3438357. ASASSN-19ado, TCP J06073081-0101501, ZTF20aavnpug, ASASSN-19ady, MASTER OT J061642.05+435617.9, J20034647+1335125, ASASSN-20kv, ASASSN-20kw, J213908.79+161240.2,...
We present time-series photometry during eruption of the extremely fast nova V1674 Herculis (Nova Her 2021). The 2021 light curve showed periodic signals at 0.152921(3) d and 501.486(5) s, which we interpret as respectively orbital white dwarf spin-periods in underlying binary. also detected a sideband signal /difference/ frequency between these two clocks. During first 15 days outburst, spin-period appears to have increased by 0.014(1)%. This increase probably arose from sudden loss...
We report on the multi-wavelength photometry of 2018 superoutburst in EG Cnc. have detected stage A superhumps and long-lasting late-stage via optical constrained binary mass ratio its possible range. The median value is 0.048 upper limit 0.057, which still implies that Cnc one candidates for period bouncer. This object also showed multiple rebrightenings this superoutburst, are same as those previous 1996--1997 despite difference main superoutburst. would represent rebrightening type...
Abstract There are several peculiar long-period dwarf-nova-like objects that show rare, low-amplitude outbursts with highly ionized emission lines; 1SWASP J162117+441254, BD Pav, and V364 Lib among them. Some researchers even doubt whether J1621 have the same nature as normal dwarf novae. We studied in these three via our optical photometry spectroscopy, performed numerical modeling of their orbital variations to investigate properties. found lasted for a long interval (a few tens days),...
Superoutbursts in WZ Sge-type dwarf novae (DNe) are characterized by both early superhumps and ordinary originating from the 2:1 3:1 resonances, respectively. However, some DNe show a superoutburst lacking superhumps; it is not well established how these differ superoutbursts with an superhump phase. We report time-resolved photometric observations of DN V627 Peg during its 2021 superoutburst. The detection before peak highlights that this Peg, like {in} 2014, did feature duration stage B...
We present our optical photometric observations of the 2022 eruption recurrent nova U Scorpii (U Sco) using 49,152 data points over 70 d following peak. have also analyzed its soft X-ray (0.3--1 keV) light curve by Neil Gehrels Swift Observatory. During eruption, plateau stage started 13.8--15.0 and ended 23.8--25.0 after The 14.6--15.3 38.7--39.5 Both stages later had shorter durations, peaked earlier was less luminous compared to those during Sco 2010 eruption. These suggest that there...
In this work, we present the discovery and cataloguing of a new variable star in Perseus. After its photometric study, it was concluded that were facing Scuti type which, although included ZTF catalogue periodic variables as suspected, not adequately characterised. For our used data from other sources, such aforementioned or ASAS-SN, own data. Finally, AAVSO’s The International Variable Star Index with name GSC 03319-01926.