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Papers by Nicolas Morales
Title: Early Evolution of the Outburst of Comet 17P/Holmes. Authors: Moreno, F.; Ortiz, JL; Santo... more Title: Early Evolution of the Outburst of Comet 17P/Holmes. Authors: Moreno, F.; Ortiz, JL; Santos-Sanz, P.; Morales, N.; Vidal-Núñez ...
Even though there are more than 1300 Transneptunian Objects discovered so far, less than 5% of th... more Even though there are more than 1300 Transneptunian Objects discovered so far, less than 5% of them have a well determined rotational period. We compile the results of 6 years of observations from our Kuiper Belt lightcurve survey in Spain. Our main aim was to increase the number of objects whose short-term variability has been studied in order to be
IAUC 9184 available at Central Bureau for Astronomical Telegrams.
We analyze a vast light curve database by obtaining mean rotational properties of the entire samp... more We analyze a vast light curve database by obtaining mean rotational properties of the entire sample, determining the spin frequency distribution and comparing those data with a simple model based on hydrostatic equilibrium. (1 data file).
The time series photometry of all the objects is provided as Table 3. We highlighted in bold face... more The time series photometry of all the objects is provided as Table 3. We highlighted in bold face the times corresponding to the images that we used to obtain an R magnitude calibration. The rest of the R magnitudes in the table was obtained by using the relative magnitude information. Also, in table 1 are geometric data such as geocentric and heliocentric distances. The R magnitudes that the TNOs would have if they were at 1AU from the Earth and the Sun (mR(1,1)) are also shown. No phase corrections were applied. In table 3, we present our photometric results: the name of the object and for each image we specify the Julian date (not corrected for travel time), the Relative magnitude [mag] and the 1-sigma error associated [mag], the R magnitude [mag], the filter used during observational runs, the phase angle (phi) [deg], topocentric (rh) and heliocentric (Delta) distances [AU] and the magnitude [mag] at 1AU from the Earth and at 1AU from the Sun. We highlight in bold face the date ...
CBET 2766 available at Central Bureau for Astronomical Telegrams.
Since 1992, more than 1400 Trans-Neptunian Objects (TNOs) have been discovered. Our approach to u... more Since 1992, more than 1400 Trans-Neptunian Objects (TNOs) have been discovered. Our approach to understand such objects is to study their rotations by monitoring their brightness variations. By studying the rotational properties of the TNOs a wealth of information can be obtained on their physics. So, the study of the spins and shapes of TNOs is a powerful method of gaining information on the formation and evolution of our Solar System. We have observed most of the brightest TNOs and centaurs, and compiled one of the largest lightcurves samples. The main purpose was to increase the number of objects whose short-term variability has been studied and present a homogeneous dataset trying to avoid observational biases. A dataset composed of 54 TNOs/Centaurs is reported and analyzed. Amplitudes and rotational periods have been derived for 45 of them with different degrees of reliability. For 9 objects, only an estimation of the amplitude is reported. Because most of the TNOs/Centaurs hav...
Astronomy and Astrophysics
We observed comet C/2012 S1 (ISON) during six nights in February 2013 when it was at 4.8 AU from ... more We observed comet C/2012 S1 (ISON) during six nights in February 2013 when it was at 4.8 AU from the sun. At this distance and time the comet was not very active and it was theoretically possible to detect photometric variations likely due to the rotation of the cometary nucleus. The goal of this work is to obtain differential photometry of the comet inner coma using different aperture radii in order to derive a possible rotational period. Large field of view images were obtained with a 4k x 4k CCD at the f/3 0.77m telescope of La Hita Observatory in Spain. Aperture photometry was performed in order to get relative magnitude variation versus time. Using calibrated star fields we also obtained ISON's R-magnitudes versus time. We applied a Lomb-Scargle periodogram analysis to get possible periodicities for the observed brightness variations, directly related with the rotation of the cometary nucleus. The comet light curve obtained is very shallow, with a peak-to-peak amplitude of ...
Planetary and Space Science, 2015
Since 2009 we are running a project to identify flashes produced by the impact of meteoroids on t... more Since 2009 we are running a project to identify flashes produced by the impact of meteoroids on the surface of the Moon. For this purpose we are employing small telescopes and high-sensitivity CCD video cameras. To automatically identify these events a software package called MIDAS was developed and tested. This package can also perform the photometric analysis of these flashes and estimate the value of the luminous efficiency. Besides, we have implemented in MIDAS a new method to establish which is the likely source of the meteoroids (known meteoroid stream or sporadic background). The main features of this computer program are analyzed here, and some examples of lunar impact events are presented.
Astronomy & Astrophysics, 2015
We present the results of our Moon impact flashes detection campaigns performed around the maximu... more We present the results of our Moon impact flashes detection campaigns performed around the maximum activity period of the Perseid meteor shower in 2012 and 2013. Just one flash produced by a Perseid meteoroid was detected in 2012 because of very unfavourable geometric conditions, but 12 of these were confirmed in 2013. The visual magnitude of the flashes ranged between 6.6 and 9.3. A luminous efficiency of 1.8·10 −3 has been estimated for meteoroids from this stream.
Astronomy & Astrophysics, 2014
We present results for the short-term variability of Binary Trans-Neptunian Objects (BTNOs). We p... more We present results for the short-term variability of Binary Trans-Neptunian Objects (BTNOs). We performed CCD photometric observations using the 3.58 m Telescopio Nazionale Galileo (TNG), the 1.5 m Sierra Nevada Observatory (OSN) telescope, and the 1.23 m Centro Astronómico Hispano Alemán (CAHA) telescope at Calar Alto Observatory. We present results based on five years of observations and report the short-term variability of six BTNOs. Our sample contains three classical objects: target, possible rotational periods and/or photometric amplitudes are reported. We also derived some physical properties from their lightcurves, such as density, primary and secondary sizes, and albedo. We compiled and analyzed a vast lightcurve database for Trans-Neptunian Objects (TNOs) including centaurs to determine the lightcurve amplitude and spin frequency distributions for the binary and non-binary populations. The mean rotational periods, from the Maxwellian fits to the frequency distributions, are 8.63±0.52 h for the entire sample, 8.37±0.58 h for the sample without the binary population, and 10.11±1.19 h for the binary population alone. Because the centaurs are collisionally more evolved, their rotational periods might not be so primordial. We computed a mean rotational period, from the Maxwellian fit, of 8.86±0.58 h for the sample without the centaur population, and of 8.64±0.67 h considering a sample without the binary and the centaur populations. According to this analysis, regular TNOs spin faster than binaries, which is compatible with the tidal interaction of the binaries. Finally, we examined possible formation models for several systems studied in this work and by our team in previous papers.
We obtained high precision relative astrometry and photometry of Orcus' system with respect t... more We obtained high precision relative astrometry and photometry of Orcus' system with respect to background stars. The Right Ascension residuals of an orbital fit to the astrometric data revealed a period of 9.7 ± 0.3 days, which is what one would expect to be induced by the known Orcus companion (Vanth). The residuals also are correlated with the theoretical positions
Title: Early Evolution of the Outburst of Comet 17P/Holmes. Authors: Moreno, F.; Ortiz, JL; Santo... more Title: Early Evolution of the Outburst of Comet 17P/Holmes. Authors: Moreno, F.; Ortiz, JL; Santos-Sanz, P.; Morales, N.; Vidal-Núñez ...
Even though there are more than 1300 Transneptunian Objects discovered so far, less than 5% of th... more Even though there are more than 1300 Transneptunian Objects discovered so far, less than 5% of them have a well determined rotational period. We compile the results of 6 years of observations from our Kuiper Belt lightcurve survey in Spain. Our main aim was to increase the number of objects whose short-term variability has been studied in order to be
IAUC 9184 available at Central Bureau for Astronomical Telegrams.
We analyze a vast light curve database by obtaining mean rotational properties of the entire samp... more We analyze a vast light curve database by obtaining mean rotational properties of the entire sample, determining the spin frequency distribution and comparing those data with a simple model based on hydrostatic equilibrium. (1 data file).
The time series photometry of all the objects is provided as Table 3. We highlighted in bold face... more The time series photometry of all the objects is provided as Table 3. We highlighted in bold face the times corresponding to the images that we used to obtain an R magnitude calibration. The rest of the R magnitudes in the table was obtained by using the relative magnitude information. Also, in table 1 are geometric data such as geocentric and heliocentric distances. The R magnitudes that the TNOs would have if they were at 1AU from the Earth and the Sun (mR(1,1)) are also shown. No phase corrections were applied. In table 3, we present our photometric results: the name of the object and for each image we specify the Julian date (not corrected for travel time), the Relative magnitude [mag] and the 1-sigma error associated [mag], the R magnitude [mag], the filter used during observational runs, the phase angle (phi) [deg], topocentric (rh) and heliocentric (Delta) distances [AU] and the magnitude [mag] at 1AU from the Earth and at 1AU from the Sun. We highlight in bold face the date ...
CBET 2766 available at Central Bureau for Astronomical Telegrams.
Since 1992, more than 1400 Trans-Neptunian Objects (TNOs) have been discovered. Our approach to u... more Since 1992, more than 1400 Trans-Neptunian Objects (TNOs) have been discovered. Our approach to understand such objects is to study their rotations by monitoring their brightness variations. By studying the rotational properties of the TNOs a wealth of information can be obtained on their physics. So, the study of the spins and shapes of TNOs is a powerful method of gaining information on the formation and evolution of our Solar System. We have observed most of the brightest TNOs and centaurs, and compiled one of the largest lightcurves samples. The main purpose was to increase the number of objects whose short-term variability has been studied and present a homogeneous dataset trying to avoid observational biases. A dataset composed of 54 TNOs/Centaurs is reported and analyzed. Amplitudes and rotational periods have been derived for 45 of them with different degrees of reliability. For 9 objects, only an estimation of the amplitude is reported. Because most of the TNOs/Centaurs hav...
Astronomy and Astrophysics
We observed comet C/2012 S1 (ISON) during six nights in February 2013 when it was at 4.8 AU from ... more We observed comet C/2012 S1 (ISON) during six nights in February 2013 when it was at 4.8 AU from the sun. At this distance and time the comet was not very active and it was theoretically possible to detect photometric variations likely due to the rotation of the cometary nucleus. The goal of this work is to obtain differential photometry of the comet inner coma using different aperture radii in order to derive a possible rotational period. Large field of view images were obtained with a 4k x 4k CCD at the f/3 0.77m telescope of La Hita Observatory in Spain. Aperture photometry was performed in order to get relative magnitude variation versus time. Using calibrated star fields we also obtained ISON's R-magnitudes versus time. We applied a Lomb-Scargle periodogram analysis to get possible periodicities for the observed brightness variations, directly related with the rotation of the cometary nucleus. The comet light curve obtained is very shallow, with a peak-to-peak amplitude of ...
Planetary and Space Science, 2015
Since 2009 we are running a project to identify flashes produced by the impact of meteoroids on t... more Since 2009 we are running a project to identify flashes produced by the impact of meteoroids on the surface of the Moon. For this purpose we are employing small telescopes and high-sensitivity CCD video cameras. To automatically identify these events a software package called MIDAS was developed and tested. This package can also perform the photometric analysis of these flashes and estimate the value of the luminous efficiency. Besides, we have implemented in MIDAS a new method to establish which is the likely source of the meteoroids (known meteoroid stream or sporadic background). The main features of this computer program are analyzed here, and some examples of lunar impact events are presented.
Astronomy & Astrophysics, 2015
We present the results of our Moon impact flashes detection campaigns performed around the maximu... more We present the results of our Moon impact flashes detection campaigns performed around the maximum activity period of the Perseid meteor shower in 2012 and 2013. Just one flash produced by a Perseid meteoroid was detected in 2012 because of very unfavourable geometric conditions, but 12 of these were confirmed in 2013. The visual magnitude of the flashes ranged between 6.6 and 9.3. A luminous efficiency of 1.8·10 −3 has been estimated for meteoroids from this stream.
Astronomy & Astrophysics, 2014
We present results for the short-term variability of Binary Trans-Neptunian Objects (BTNOs). We p... more We present results for the short-term variability of Binary Trans-Neptunian Objects (BTNOs). We performed CCD photometric observations using the 3.58 m Telescopio Nazionale Galileo (TNG), the 1.5 m Sierra Nevada Observatory (OSN) telescope, and the 1.23 m Centro Astronómico Hispano Alemán (CAHA) telescope at Calar Alto Observatory. We present results based on five years of observations and report the short-term variability of six BTNOs. Our sample contains three classical objects: target, possible rotational periods and/or photometric amplitudes are reported. We also derived some physical properties from their lightcurves, such as density, primary and secondary sizes, and albedo. We compiled and analyzed a vast lightcurve database for Trans-Neptunian Objects (TNOs) including centaurs to determine the lightcurve amplitude and spin frequency distributions for the binary and non-binary populations. The mean rotational periods, from the Maxwellian fits to the frequency distributions, are 8.63±0.52 h for the entire sample, 8.37±0.58 h for the sample without the binary population, and 10.11±1.19 h for the binary population alone. Because the centaurs are collisionally more evolved, their rotational periods might not be so primordial. We computed a mean rotational period, from the Maxwellian fit, of 8.86±0.58 h for the sample without the centaur population, and of 8.64±0.67 h considering a sample without the binary and the centaur populations. According to this analysis, regular TNOs spin faster than binaries, which is compatible with the tidal interaction of the binaries. Finally, we examined possible formation models for several systems studied in this work and by our team in previous papers.
We obtained high precision relative astrometry and photometry of Orcus' system with respect t... more We obtained high precision relative astrometry and photometry of Orcus' system with respect to background stars. The Right Ascension residuals of an orbital fit to the astrometric data revealed a period of 9.7 ± 0.3 days, which is what one would expect to be induced by the known Orcus companion (Vanth). The residuals also are correlated with the theoretical positions