This section illustrates a small selection of the observational work conducted at Flarestar Observatory. Please consider any results shown here as preliminary as these are subject to change following thorough analysis. Please consult the Scientific Publications page of this website to find the final conclusions and/or confer with relevant organizations to acquire the latest findings.
A selection of older observational data can be accessed through this link Here
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Astronomical Observations: A Statistical Overview (2023)
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2022 February 22
Flarestar's discovery of an unknown variable star in the Alpha Persei Cluster
That’s a new variable star! The star known as Cl Melotte 20 523 is the 523rd star that has been formerly identified to a true member of the Melotte 20 star cluster. Until a few days ago, the star was not known to be a variable star until the Maltese researcher Stephen M. Brincat has discovered it to be so from Flarestar Observatory in San Gwann.
Melotte 20 is more popularly referred to as the Alpha Persei star cluster where the brightest members are seen to surround the brightest star of the constellation Perseus. The Alpha Persei cluster can be seen without any optical aid but is spectacular through binoculars as several members are seen within the field of view. Cl Melotte 20 523 is a fainter member of the cluster that can been seen with a small telescope or captured through a DSLR camera with a standard lens.
The star was monitored through a CCD camera over three nights. The results divulged a cyclic variability in its brightness over a regular period of 102.8 minutes. Additional data gathered from professional surveys substantiated the results obtained the discoverer that confirmed the established period. The data acquired showed that Cl Melotte 20 523 is a bluish-white star that belongs to a subclass of young pulsating stars known as Delta Scuti stars. As a result, the new variable star was given the variable star ID: 000-BPG-960 by the American Association of Variable Star Observers.
https://www.aavso.org/vsx/index.php?view=detail.top&oid=2226053
Flarestar's discovery of an unknown variable star in the Alpha Persei Cluster
That’s a new variable star! The star known as Cl Melotte 20 523 is the 523rd star that has been formerly identified to a true member of the Melotte 20 star cluster. Until a few days ago, the star was not known to be a variable star until the Maltese researcher Stephen M. Brincat has discovered it to be so from Flarestar Observatory in San Gwann.
Melotte 20 is more popularly referred to as the Alpha Persei star cluster where the brightest members are seen to surround the brightest star of the constellation Perseus. The Alpha Persei cluster can be seen without any optical aid but is spectacular through binoculars as several members are seen within the field of view. Cl Melotte 20 523 is a fainter member of the cluster that can been seen with a small telescope or captured through a DSLR camera with a standard lens.
The star was monitored through a CCD camera over three nights. The results divulged a cyclic variability in its brightness over a regular period of 102.8 minutes. Additional data gathered from professional surveys substantiated the results obtained the discoverer that confirmed the established period. The data acquired showed that Cl Melotte 20 523 is a bluish-white star that belongs to a subclass of young pulsating stars known as Delta Scuti stars. As a result, the new variable star was given the variable star ID: 000-BPG-960 by the American Association of Variable Star Observers.
https://www.aavso.org/vsx/index.php?view=detail.top&oid=2226053
2022 January 25
Research Paper: Rotation period determination of 3 main-belt asteroids from Malta
Pleased to notify of our research that was published in the peer reviewed scientific journal - the Minor Planet Bulletin (Volume 49 Issue 1) where the rotation period of three asteroids have been derived through photometric means. The asteroids that were monitored were observed from two observatories at Naxxar and San Gwann.
This paper is the result of an observational collaborative campaign where at the time of observation, the rotation period of three asteroids was unknown to the astronomical community. Specifically, we estimated that the days over 2229 Mezzarco lasts for 10.241 hours; for 3648 Raffinetti, 5.177 hours; and for 3919 Maryanning, 7.094 hours.
This work is important in that it characterises the main properties of the asteroid population. Recently, this information is becoming increasingly important for space missions that are aimed to study the properties of individual asteroids.
A link to our paper can be found below.
This research paper is available through the SAO/NASA Astrophysics Data System at
https://ui.adsabs.harvard.edu/abs/2022MPBu...49....1G/abstract
Authors: Charles Galdies; Stephen M. Brincat
Research Paper: Rotation period determination of 3 main-belt asteroids from Malta
Pleased to notify of our research that was published in the peer reviewed scientific journal - the Minor Planet Bulletin (Volume 49 Issue 1) where the rotation period of three asteroids have been derived through photometric means. The asteroids that were monitored were observed from two observatories at Naxxar and San Gwann.
This paper is the result of an observational collaborative campaign where at the time of observation, the rotation period of three asteroids was unknown to the astronomical community. Specifically, we estimated that the days over 2229 Mezzarco lasts for 10.241 hours; for 3648 Raffinetti, 5.177 hours; and for 3919 Maryanning, 7.094 hours.
This work is important in that it characterises the main properties of the asteroid population. Recently, this information is becoming increasingly important for space missions that are aimed to study the properties of individual asteroids.
A link to our paper can be found below.
This research paper is available through the SAO/NASA Astrophysics Data System at
https://ui.adsabs.harvard.edu/abs/2022MPBu...49....1G/abstract
Authors: Charles Galdies; Stephen M. Brincat
Paper: ExoClock project II: A large-scale integrated study with 180 updated exoplanet ephemerides
The paper in caption by Kokori A., et al. (for which I appear as co-author) has been published as arXiv preprint that is available through the link below:
https://arxiv.org/abs/2110.13863
ExoClock is a project to monitor transiting exoplanets in order to keep their ephemerides up-to-date for the upcoming launch of the Ariel (Atmospheric Remote-sensing Infrared Exoplanet Large-survey) satellite that will conduct a 4-year mission to discover the composition of exoplanets and how they evolved.
The paper in caption by Kokori A., et al. (for which I appear as co-author) has been published as arXiv preprint that is available through the link below:
https://arxiv.org/abs/2110.13863
ExoClock is a project to monitor transiting exoplanets in order to keep their ephemerides up-to-date for the upcoming launch of the Ariel (Atmospheric Remote-sensing Infrared Exoplanet Large-survey) satellite that will conduct a 4-year mission to discover the composition of exoplanets and how they evolved.
2021 October 05
Paper " Properties of slowly rotating asteroids from the Convex Inversion Thermophysical Model"
by Marciniak et al.
Here is a study where I appear as a co-author concerning the properties of slowly rotating asteroids from the Convex Inversion Thermophysical (CIT) Model. The results obtained by this study were released through a research paper lead by astronomer Dr. Marciniak published in the Journal ‘Astronomy & Astrophysics’.
Most asteroids that have rotation periods longer than 12 hours are less likely to be observed, as observers tend to pick up easier targets that take a lesser number of nights for their rotation periods to be determined. It is well known that observer bias may skew our holistic overview of the rotation rates of the known asteroid population.
To address this discrepancy, this study aimed to minimize our selection effects by targeting slow rotating asteroids with low light variations. The asteroids under study were observed through visible and infrared bandpass for which the former data was collected through ground-based observatories while for the latter, data was gathered from space observatories to optimize the modeling process.
More details can be obtained through the full version of the paper that is available from the link below:
https://arxiv.org/abs/2109.00463
Paper " Properties of slowly rotating asteroids from the Convex Inversion Thermophysical Model"
by Marciniak et al.
Here is a study where I appear as a co-author concerning the properties of slowly rotating asteroids from the Convex Inversion Thermophysical (CIT) Model. The results obtained by this study were released through a research paper lead by astronomer Dr. Marciniak published in the Journal ‘Astronomy & Astrophysics’.
Most asteroids that have rotation periods longer than 12 hours are less likely to be observed, as observers tend to pick up easier targets that take a lesser number of nights for their rotation periods to be determined. It is well known that observer bias may skew our holistic overview of the rotation rates of the known asteroid population.
To address this discrepancy, this study aimed to minimize our selection effects by targeting slow rotating asteroids with low light variations. The asteroids under study were observed through visible and infrared bandpass for which the former data was collected through ground-based observatories while for the latter, data was gathered from space observatories to optimize the modeling process.
More details can be obtained through the full version of the paper that is available from the link below:
https://arxiv.org/abs/2109.00463
2021 September 20
Poster Paper "Confirmation of the Exoplanet KELT-18b transit time"
Poster Paper "Confirmation of the Exoplanet KELT-18b transit time"
Above please find a poster paper concerning the observation of Exoplanet KELT-18b from Malta to refine the predicted time of transit.
Transits occur when an exoplanet crosses over the surface of its host star as seen from Earth. As exoplanets are much smaller than the apparent size of their parent stars, the observed dip in brightness is extremely small and thus it can be quite challenging to record the event if not observed under the right conditions.
Despite the limitations present during the KELT-18b observation run, subsequent analysis of the observations showed that useful scientific data was obtained even though the full transit event as observed from Malta could not be fully recorded. This was due to the timing of the event that began shortly after sunset occurred.
Transits occur when an exoplanet crosses over the surface of its host star as seen from Earth. As exoplanets are much smaller than the apparent size of their parent stars, the observed dip in brightness is extremely small and thus it can be quite challenging to record the event if not observed under the right conditions.
Despite the limitations present during the KELT-18b observation run, subsequent analysis of the observations showed that useful scientific data was obtained even though the full transit event as observed from Malta could not be fully recorded. This was due to the timing of the event that began shortly after sunset occurred.
2021 July 26
Paper "Optical Variability Correlated with X-ray Spectral Transition in the Black-Hole Transient ASASSN-18ey = MAXI J1820+070" by Niijima K. et al.
We are glad to announce that the study about the Black hole transient ASASN-18ey has been published. For this piece of work, starting from the time of outburst in 2018, over 30 (thirty) thousand photometric observations have been acquired by Flarestar Observatory. These observations have been utilized by the primary author Dr Keito Niijima, to derive his conclusions in his paper. From Flarestar, we have been monitoring ASASSN-18ey extensively through the optical band over several months where it was found that the object was far more dynamic than expected. Below please find the abstract to the paper with direct links to the full paper that shows a correlation between optical variability and and X-ray emission. Furthermore, this paper provides for the first time ever, the dynamical estimate of the binary mass ratio through the use of the optical periodic variations
ASASSN-18ey is a binary system where the primary component is a black-hole, while the secondary component is a dwarf star of less than 1 solar mass.
Paper "Optical Variability Correlated with X-ray Spectral Transition in the Black-Hole Transient ASASSN-18ey = MAXI J1820+070" by Niijima K. et al.
We are glad to announce that the study about the Black hole transient ASASN-18ey has been published. For this piece of work, starting from the time of outburst in 2018, over 30 (thirty) thousand photometric observations have been acquired by Flarestar Observatory. These observations have been utilized by the primary author Dr Keito Niijima, to derive his conclusions in his paper. From Flarestar, we have been monitoring ASASSN-18ey extensively through the optical band over several months where it was found that the object was far more dynamic than expected. Below please find the abstract to the paper with direct links to the full paper that shows a correlation between optical variability and and X-ray emission. Furthermore, this paper provides for the first time ever, the dynamical estimate of the binary mass ratio through the use of the optical periodic variations
ASASSN-18ey is a binary system where the primary component is a black-hole, while the secondary component is a dwarf star of less than 1 solar mass.
2021 April 14
Paper Abstract: 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 of Kyoto University and through VSNET collaboration. Our spectroscopic observations 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, TCP J20034647+1335125, ASASSN-20kv, ASASSN-20kw, MASTER OT J213908.79+161240.2, and ASASSN-20mf) were previously unknown systems, and our observations enabled quick classification of their transient type. These results illustrate that Seimei telescope has the capability to conduct quick follow-up observations of unknown transients. Our photometric observations yielded that 11 objects are WZ Sge-type dwarf novae and their candidates, and the other six objects are SU UMa-type dwarf novae and their candidates. The He II 4686Å~ emission line was clearly detected among ASASSN-19ado, TCP J06073081-0101501 and MASTER OT J213908.79+161240.2, whose association with a spiral arm structure in an accretion disk has been suggested in the previous studies. Our result suggests that a higher-inclination system shows a stronger emission line of He II 4686Å, as well as larger-amplitude early superhumps.
Link to access paper: https://ui.adsabs.harvard.edu/abs/2021arXiv210404948T/abstract
Link to access paper: https://ui.adsabs.harvard.edu/abs/2021arXiv210404948T/abstract
2020 September 02
Paper 'Multi-wavelength photometry during the 2018 superoutburst of the WZ Sge-type dwarf nova EG Cancri' by Dr M. Kimura
Observations from Flarestar Observatory have been used by Dr Kimura for her research. The variable star EG was observed through photometric means during its 2018 outburst. further details are available through the image below. Please right click and open in a new window to enlarge.
Paper 'Multi-wavelength photometry during the 2018 superoutburst of the WZ Sge-type dwarf nova EG Cancri' by Dr M. Kimura
Observations from Flarestar Observatory have been used by Dr Kimura for her research. The variable star EG was observed through photometric means during its 2018 outburst. further details are available through the image below. Please right click and open in a new window to enlarge.
2020 July 19
Collaborative Campaign by Maltese and Spanish researchers uncover the rotation period of 3 asteroids
The latest issue of the scientific journal - the Minor Planet Bulletin (Volume 47 Issue 3) has published our paper where we determined through photometric means, the rotational period of three asteroids 1755 LORBACH, 4857 ALTGAMIA and (48540) 1993 TW8. This paper is the result of an observational collaborative campaign conducted by three observatories with two situated in Malta and the other at La Palma, Spain. At the time of observation, the rotation period of these asteroids were unknown to the astronomical community.
The following observatories contributed observations towards this campaign:
· Flarestar Observatory (171), San Gwann, Malta.
· Tacande Observatory, La Palma, Spain
· Znith Observatory, Naxxar, Malta
Asteroid (1755) Lorbach rotation period was determined by Flarestar Observatory over 5 nights of observation during the month of February 2020. Based on 222 observations, the rotation period for this outer main-belt asteroid was found to be 7.973 ± 0.001 hours with a magnitude range of 0.45 ± 0.03 magnitude.
(4857) Altgamia belongs to the Phocaea (PHO) asteroid family and is located within the main-belt asteroid region. This asteroid was observed over 4 nights from 2020 February 7 to 15 from Znith Observatory, Malta. 253 observations were acquired to determine the rotation period of (4857) Altgamia as 9.034 ± 0.003 h with an amplitude of 0.26 ± 0.05 mag.
(48540) 1993 TW8 is a main-belt asteroid and was observed from 2019 October 02 to November 28 over 12 nights with observations from Flarestar Observatory and Tacande Observatory where each observatory contributed 6 nights. We acquired 887 observations on this long rotational period asteroid. We determined its rotation period as 25.037 ± 0..004 h with an amplitude of 0.24 ± 0.05 mag
Collaborative Campaign by Maltese and Spanish researchers uncover the rotation period of 3 asteroids
The latest issue of the scientific journal - the Minor Planet Bulletin (Volume 47 Issue 3) has published our paper where we determined through photometric means, the rotational period of three asteroids 1755 LORBACH, 4857 ALTGAMIA and (48540) 1993 TW8. This paper is the result of an observational collaborative campaign conducted by three observatories with two situated in Malta and the other at La Palma, Spain. At the time of observation, the rotation period of these asteroids were unknown to the astronomical community.
The following observatories contributed observations towards this campaign:
· Flarestar Observatory (171), San Gwann, Malta.
· Tacande Observatory, La Palma, Spain
· Znith Observatory, Naxxar, Malta
Asteroid (1755) Lorbach rotation period was determined by Flarestar Observatory over 5 nights of observation during the month of February 2020. Based on 222 observations, the rotation period for this outer main-belt asteroid was found to be 7.973 ± 0.001 hours with a magnitude range of 0.45 ± 0.03 magnitude.
(4857) Altgamia belongs to the Phocaea (PHO) asteroid family and is located within the main-belt asteroid region. This asteroid was observed over 4 nights from 2020 February 7 to 15 from Znith Observatory, Malta. 253 observations were acquired to determine the rotation period of (4857) Altgamia as 9.034 ± 0.003 h with an amplitude of 0.26 ± 0.05 mag.
(48540) 1993 TW8 is a main-belt asteroid and was observed from 2019 October 02 to November 28 over 12 nights with observations from Flarestar Observatory and Tacande Observatory where each observatory contributed 6 nights. We acquired 887 observations on this long rotational period asteroid. We determined its rotation period as 25.037 ± 0..004 h with an amplitude of 0.24 ± 0.05 mag
2020 June 15
Observation of Exoplanet TrES-3b
The Exoplanet TrES-b transit (eclipse) have been observed autonomously from Flarestar Observatory (Malta) on 2020 June 12. This exercise has been conducted in order to test the capabilities of the current configuration that is being employed for research work on variable stars and asteroids.
The results obtained through this exercise shows that the system has the potential capability to do such work as the TrES-3b transit was recorded successfully. The results obtained are in agreement with those published.
Our results indicate that mid-transit occurred on HJD 2459013.57605 ± 0.00060 with an eclipse duration of 80.03 ± 2.3 minutes and eclipse depth of 0.0250 ± 0.0013 magnitude.
Observation of Exoplanet TrES-3b
The Exoplanet TrES-b transit (eclipse) have been observed autonomously from Flarestar Observatory (Malta) on 2020 June 12. This exercise has been conducted in order to test the capabilities of the current configuration that is being employed for research work on variable stars and asteroids.
The results obtained through this exercise shows that the system has the potential capability to do such work as the TrES-3b transit was recorded successfully. The results obtained are in agreement with those published.
Our results indicate that mid-transit occurred on HJD 2459013.57605 ± 0.00060 with an eclipse duration of 80.03 ± 2.3 minutes and eclipse depth of 0.0250 ± 0.0013 magnitude.
2020 June 08
Study on Carbon Star published in Research in Astronomy and Astrophysics.
Following my announcement of the discovery of the variable star GSC 03333-00416 (aka CGCS 673), we are pleased to notify that our research paper on this star entitled, “Carbon Star CGCS 673 identified as a Semi-regular variable star” has been accepted and published in the renowned Journal Research in Astronomy and Astrophysics.
Following the official recognition of GSC 03333-00416 variable star, we continued our observations of this target to get more data. A total of 348 observations were carried out over a 118-day period that permitted us to refine the initial period to 135.1 ± 1.3 days. Supplementary V-band photometry observations provided additional physical characteristics on the star.
The shape of the light curve morphology of the star CGCS 673 shows that it belongs to the Semi-regular variable star classification.
The full version of the paper can be accessed through the link below:
http://www.raa-journal.org/docs/papers_accepted/2020-0119.pdf
Carbon Star CGCS 673 identified as a Semi-regular variable star
Stephen M. Brincat, C. Galdies and K. Hills
ABSTRACT: This study shows that the carbon star CGCS 673 is a semi-regular (SR) variable star with a period of 135 d and an amplitude of 0.18 magnitudes in the V-band. The light curve obtained by this study correlates well with the SR classification as the photometric data obtained shows noticeable periodicity in the light changes of CGCS 673 that is occasionally interrupted by a period of irregular variability. The derived period and colour index obtained from our data and those from professional databases indicate that the attributes of this star fall within the parameters of the Semi-Regular class of variable stars. Following our notification of the discovery that this star is a variable source, CGCS 673 has received the AAVSO Unique Identifier as (AAVSO UID) 000-BMZ-492.
2020 May 30
Discovery of a New Variable Star in the Constellation of Libra
A new variable star was recently discovered from Malta from Flarestar Observatory. The star (GSC 00586-00270) is located in the constellation of Libra and has now been officially classified as a new variable star, pertaining to the DY Draconis class. GSC 05586-00270 is a dwarf star (radius 2.1 times of the Sun) and is 1253 light years away. Its relative vicinity to Earth has made it bright enough to be detectable visually through an 8-inch aperture telescope. The star varies from magnitude 12.07 to 12.30 mV every 9.10 days.
The light variability of this single star is caused by the axial rotation of the star that is divulged by the presence of star spots and other chromospheric activity. BY Dra stars also exhibit flares similar to those on the sun but on a relatively larger scale.
This variable was discovered during the analysis in search of chromospheric activity on a nearby field star. The brightness of variable stars is determined by comparing the target star brightness with those stars that have known brightness. During the analysis, an abrupt rise in brightness that is reminiscent to a typical flaring event was detected on GSC 05586-00270. This prompted me to look closely whether this supposedly stable star had a variable light output.
Professional surveys nowadays routinely cover the whole sky. The ASAS-SN Survey is one such survey and further data on this star was retrieved and analysed. Analysis through the Lomb-Scargle algorithm uncovered a prominent period of 9.1 days. This result indicates that the star rotates on its axis every 9.10 days. In contrast our star the sun, takes 26.24 days (synodic rotation) to do so.
The findings above were reported to the AAVSO International Variable Star database (VSX) and following a review period by the VSX Team, the star was officially recognized as a new variable star with the discovery credit attributed to my name.
Details of the new variable star can be found at the following VSX link:
https://www.aavso.org/vsx/index.php?view=detail.top&oid=1545396
Further research is ongoing in order to know more about the physical properties of this star.
Discovery of a New Variable Star in the Constellation of Libra
A new variable star was recently discovered from Malta from Flarestar Observatory. The star (GSC 00586-00270) is located in the constellation of Libra and has now been officially classified as a new variable star, pertaining to the DY Draconis class. GSC 05586-00270 is a dwarf star (radius 2.1 times of the Sun) and is 1253 light years away. Its relative vicinity to Earth has made it bright enough to be detectable visually through an 8-inch aperture telescope. The star varies from magnitude 12.07 to 12.30 mV every 9.10 days.
The light variability of this single star is caused by the axial rotation of the star that is divulged by the presence of star spots and other chromospheric activity. BY Dra stars also exhibit flares similar to those on the sun but on a relatively larger scale.
This variable was discovered during the analysis in search of chromospheric activity on a nearby field star. The brightness of variable stars is determined by comparing the target star brightness with those stars that have known brightness. During the analysis, an abrupt rise in brightness that is reminiscent to a typical flaring event was detected on GSC 05586-00270. This prompted me to look closely whether this supposedly stable star had a variable light output.
Professional surveys nowadays routinely cover the whole sky. The ASAS-SN Survey is one such survey and further data on this star was retrieved and analysed. Analysis through the Lomb-Scargle algorithm uncovered a prominent period of 9.1 days. This result indicates that the star rotates on its axis every 9.10 days. In contrast our star the sun, takes 26.24 days (synodic rotation) to do so.
The findings above were reported to the AAVSO International Variable Star database (VSX) and following a review period by the VSX Team, the star was officially recognized as a new variable star with the discovery credit attributed to my name.
Details of the new variable star can be found at the following VSX link:
https://www.aavso.org/vsx/index.php?view=detail.top&oid=1545396
Further research is ongoing in order to know more about the physical properties of this star.
TCP J21040470+4631129