F. Manzini - Academia.edu (original) (raw)
Papers by F. Manzini
Earth, Moon, and Planets, 2006
The astronomer's telegram, 2020
Monthly Notices of the Royal Astronomical Society
The recent close approach of comet C/2020 F3 (NEOWISE) allowed us to study the morphology of its ... more The recent close approach of comet C/2020 F3 (NEOWISE) allowed us to study the morphology of its inner coma. From the measurement of the dust ejection velocity on spiral structures expanding around the nucleus, we estimated a mean deprojected expansion velocity Vd = 1.11 ± 0.08 km s−1. Assuming that a new shell formed after every rotation of the comet, a period of 7.8 ± 0.2 h was derived. The spin axis orientation was estimated at RA 210° ± 10°, Dec. +35° ± 10°. The coma morphology appears related to two strong, diametrically opposite emissions located at mid-latitudes on the nucleus. A qualitative modelling of the coma produced consistent results with a wide range of dust sizes (0.80–800 μm), with inversely correlated densities (0.003–3.0 g cm−3). Images taken with Vj and r-Sloan filters showed a greater concentration of dust in the first two shells, and an increasing density of radicals emitting in the B and V band passes from the third shell outwards. Striae-like structures in ...
We report the detection of transits by the 3.1M Jup companion to the V=8.17 G0V star HD 17156. Th... more We report the detection of transits by the 3.1M Jup companion to the V=8.17 G0V star HD 17156. The transit was observed by three independant observers on Sept. 9/10, 2007 (two in central Italy and one in the Canary Islands), who obtained detections at confidence levels of 3.0 σ, 5.3 σ, and 7.9 σ, respectively. The observations were carried out under the auspices of the Transitsearch.org network, which organizes follow-up photometric transit searches of known planet-bearing stars during the time intervals when transits are expected to possibly occur. Analyses of the 7.9 σ data set indicates a transit depth d = 0.0062 ± 0.0004, and a transit duration t = 186 ± 5 min. These values are consistent with the transit of a Jupiter-sized planet with an impact parameter b = a cos i/R ⋆ ∼ 0.8. This planet occupies a unique regime among known transiting extrasolar planets, both as a result of its large orbital eccentricity (e = 0.67) and long orbital period (P = 21.2d). The planet receives a 26-fold variation in insolation during the course of its orbit, which will make it a useful object for characterization of exoplanetary atmospheric dynamics.
Astronomy & Astrophysics
Context. Recent results for asteroid rotation periods from the TESS mission showed how strongly p... more Context. Recent results for asteroid rotation periods from the TESS mission showed how strongly previous studies have underestimated the number of slow rotators, revealing the importance of studying those targets. For most slowly rotating asteroids (those with P > 12 h), no spin and shape model is available because of observation selection effects. This hampers determination of their thermal parameters and accurate sizes. Also, it is still unclear whether signatures of different surface material properties can be seen in thermal inertia determined from mid-infrared thermal flux fitting. Aims. We continue our campaign in minimising selection effects among main belt asteroids. Our targets are slow rotators with low light-curve amplitudes. Our goal is to provide their scaled spin and shape models together with thermal inertia, albedo, and surface roughness to complete the statistics. Methods. Rich multi-apparition datasets of dense light curves are supplemented with data from Kepler...
... M.; Sergeev, A.; Kozlov, V.; Camarasa, J.; Nicolas, J.; Bel, J.; Martignoni, M.; Noel, T.; Br... more ... M.; Sergeev, A.; Kozlov, V.; Camarasa, J.; Nicolas, J.; Bel, J.; Martignoni, M.; Noel, T.; Bryssinck, E.; Soulier, JF; Diepvens, A.; Gao, X.; Hui, M.-T.; Zhao, HB; Yao, JS; Zhaori, GT; Lu, H.; Wang, M.; Hong, RQ; Hu, LF; Xia, Y.; Hills, K.; Takahashi, T.; Camilleri, P.; Baroni, S.; Concari, P ...
Astrophysics and Space Science, 2012
Extensive observations of comet C/2004 Q2 (Machholz) were carried out between August 2004 and May... more Extensive observations of comet C/2004 Q2 (Machholz) were carried out between August 2004 and May 2005. The images obtained were used to investigate the comet"s inner coma features at resolutions between 350 and 1500 km/pixel. A photometric analysis of the dust outflowing from the comet"s nucleus and the study of the motion of the morphological structures in the inner coma indicated that the rotation period of the nucleus was most likely around 0.74 days. A thorough investigation of the inner coma morphology allowed us to observe two main active sources on the comet"s nucleus, at a latitude of +85° ± 5° and +45° ± 5°, respectively. Further sources have been observed, but their activity ran out quite rapidly over time; the most relevant was at lat com. = 25° ± 5°. Graphic simulations of the geometrical conditions of observation of the inner coma were compared with the images and used to determine a pole orientation at RA=95° ± 5°, Dec=+35° ± 5°. The comet"s spin axis was lying nearly on the plane of the sky during the first decade of December 2004.
Monthly Notices of the Royal Astronomical Society: Letters
We processed images taken with the Hubble Space Telescope (HST) to investigate any morphological ... more We processed images taken with the Hubble Space Telescope (HST) to investigate any morphological features in the inner coma suggestive of a peculiar activity on the nucleus of the interstellar comet 2I/Borisov. The coma shows an evident elongation, in the position angle (PA) ∼0○-180○ direction, which appears related to the presence of a jet originating from a single active source on the nucleus. A counterpart of this jet directed towards PA ∼10○ was detected through analysis of the changes of the inner coma morphology on HST images taken in different dates and processed with different filters. These findings indicate that the nucleus is probably rotating with a spin axis projected near the plane of the sky and oriented at PA ∼100○-280○, and that the active source is lying in a near-equatorial position. Subsequent observations of HST allowed us to determine the direction of the spin axis at RA = 17h20m ±15○ and Dec = −35○ ±10○. Photometry of the nucleus on HST images of 12 October 20...
Icarus
We studied a sample of 93 asteroid pairs, i.e., pairs of genetically related asteroids that are o... more We studied a sample of 93 asteroid pairs, i.e., pairs of genetically related asteroids that are on highly similar heliocentric orbits. We estimated times elapsed since separation of pair members (i.e., pair age) that are between 7 × 10 3 yr and a few 10 6 yr. With photometric observations, we derived the rotation periods P 1 for all the primaries (i.e., the larger members of asteroid pairs) and a sample of secondaries (the smaller pair members). We derived the absolute magnitude differences of the studied asteroid pairs that provide their mass ratios q. For a part of the studied pairs, we refined their WISE geometric albedos and collected or estimated their taxonomic classifications. For 17 asteroid pairs, we also determined their pole positions. In two pairs where we obtained the spin poles for both pair components, we saw the same sense of rotation for both components and constrained the angles between their original spin vectors at the time of their separation. We found that the primaries of 13 asteroid pairs in our sample are actually binary or triple systems, i.e., they have one or two bound, orbiting secondaries (satellites). As a by-product, we found also 3 new young asteroid clusters (each of them consisting of three known asteroids on highly similar heliocentric orbits). We compared the obtained asteroid pair data with theoretical predictions and discussed their implications. We found that 86 of the 93 studied asteroid pairs follow the trend of primary rotation period vs mass ratio that was found by Pravec et al. (2010). Of the 7 outliers, 3 appear insignificant (may be due to our uncertain or incomplete knowledge of the three pairs), but 4 are high mass ratio pairs that were unpredicted by the theory of asteroid pair formation by rotational fission. We discuss a (remotely) possible way that they could be created by rotational fission of flattened parent bodies followed by reshaping of the formed components. The 13 asteroid pairs with binary primaries are particularly interesting systems that place important constraints on formation and evolution of asteroid pairs. We present two hypotheses for their formation: The asteroid pairs having both bound and unbound secondaries could be "failed asteroid clusters", or they could be formed by a cascade primary spin fission process. Further studies are needed to reveal which of these two hypotheses for formation of the paired binary systems is real.
Astronomy & Astrophysics
Context. Earlier work suggests that slowly rotating asteroids should have higher thermal inertias... more Context. Earlier work suggests that slowly rotating asteroids should have higher thermal inertias than faster rotators because the heat wave penetrates deeper into the subsurface. However, thermal inertias have been determined mainly for fast rotators due to selection effects in the available photometry used to obtain shape models required for thermophysical modelling (TPM). Aims. Our aims are to mitigate these selection effects by producing shape models of slow rotators, to scale them and compute their thermal inertia with TPM, and to verify whether thermal inertia increases with the rotation period. Methods. To decrease the bias against slow rotators, we conducted a photometric observing campaign of main-belt asteroids with periods longer than 12 h, from multiple stations worldwide, adding in some cases data from WISE and Kepler space telescopes. For spin and shape reconstruction we used the lightcurve inversion method, and to derive thermal inertias we applied a thermophysical mo...
Astronomy & Astrophysics
Context. The available set of spin and shape modelled asteroids is strongly biased against slowly... more Context. The available set of spin and shape modelled asteroids is strongly biased against slowly rotating targets and those with low lightcurve amplitudes. This is due to the observing selection effects. As a consequence, the current picture of asteroid spin axis distribution, rotation rates, radiometric properties, or aspects related to the object’s internal structure might be affected too. Aims. To counteract these selection effects, we are running a photometric campaign of a large sample of main belt asteroids omitted in most previous studies. Using least chi-squared fitting we determined synodic rotation periods and verified previous determinations. When a dataset for a given target was sufficiently large and varied, we performed spin and shape modelling with two different methods to compare their performance. Methods. We used the convex inversion method and the non-convex SAGE algorithm, applied on the same datasets of dense lightcurves. Both methods search for the lowest devi...
Icarus
Eos family was created during a catastrophic impact about 1.3 Gyr ago. Rotation states of individ... more Eos family was created during a catastrophic impact about 1.3 Gyr ago. Rotation states of individual family members contain information about the history of the whole population. We aim to increase the number of asteroid shape models and rotation states within the Eos collision family, as well as to revise previously published shape models from the literature. Such results can be used to constrain theoretical collisional and evolution models of the family, or to estimate other physical parameters by a thermophysical modeling of the thermal infrared data. We use all available disk-integrated optical data (i.e., classical dense-in-time photometry obtained from public databases and through a large collaboration network as well as sparse-in-time individual measurements from a few sky surveys) as input for the convex inversion method, and derive 3D shape models of asteroids together with their rotation periods and orientations of rotation axes. We present updated shape models for 15 asteroids and new shape model determinations for 16 asteroids. Together with the already published models from the publicly available DAMIT database, we compiled a sample of 56 Eos family members with known shape models that we used in our analysis of physical properties within the family. Rotation states of asteroids smaller than ∼20 km are heavily influenced by the YORP effect, whilst the large objects more or less retained their rotation state properties since the family creation. Moreover, we also present a shape model and bulk density of asteroid (423) Diotima, an interloper in the Eos family, based on the disk-resolved data obtained by the Near InfraRed Camera (Nirc2) mounted on the W.M. Keck II telescope.
Many new constellation figures have been proposed over the ages. Not all have been accepted, and ... more Many new constellation figures have been proposed over the ages. Not all have been accepted, and here the authors examine some of the constellations which have not survived.
Federico Manzini report the discovery by Alessandro Dimai, on behalf of the CROSS Program (cf. IA... more Federico Manzini report the discovery by Alessandro Dimai, on behalf of the CROSS Program (cf. IAUC 7373) with the 0.5-m "Ullrich" telescope of the Col Druscié observatory (Cortina d'Ampezzo- Italy), of an apparent supernova in IC 178 at a magnitude of 15.5 about; two unfiltered CCD images taken on 2005 July 15.05 (limiting magnitude about 19.0) shown the new object. The presence of the object with magnitude 15.4 about, is confirmed by other two unfiltered CCD images taken on 2005 July 16.01 (limiting magnitude about 18.5) with the same telescope.
Earth Moon and Planets, 1997
Hundreds of high quality CCD images obtained by the GAT group with the 33.5 cm reflector of the S... more Hundreds of high quality CCD images obtained by the GAT group with the 33.5 cm reflector of the Sozzago Astronomical Observatory (SAS) provide a detailed insight into the temporal evolution of comet Hale-Bopp. The images cover the time period from May 1996 until May 1997 and allowed us to analyze various near nucleus phenomena. Among them are jet structures that
IAUC 8588 available at Central Bureau for Astronomical Telegrams.
The minor planet (1139) Atami showed mutual eclipses features on its light curves during its 2005... more The minor planet (1139) Atami showed mutual eclipses features on its light curves during its 2005 opposition. Photometric and radar analysis reveal the binarity of this system composed by two bodies of the same size (7.4x4.4x4.4 km 15%) separated by about 17.7 1.1 km. Rotations and revolutions are synchronous and the period is T =1.145 0.002 days. From a model, we derived bulk density =2.2 0.5 g/cm3. Spectrometry was performed during an eclipse. It reveals that the two bodies have the same reectance
Monthly Notices of the Royal Astronomical Society, 2015
Asteroid (234) Barbara is the prototype of a category of asteroids that has been shown to be extr... more Asteroid (234) Barbara is the prototype of a category of asteroids that has been shown to be extremely rich in refractory inclusions, the oldest material ever found in the Solar System. It exhibits several peculiar features, most notably its polarimetric behavior. In recent years other objects sharing the same property (collectively known as "Barbarians") have been discovered. Interferometric observations in the mid-infrared with the ESO VLTI suggested that (234) Barbara might have a bi-lobated shape or even a large companion satellite. We use a large set of 57 optical lightcurves acquired between 1979 and 2014, together with the timings of two stellar occultations in 2009, to determine the rotation period, spin-vector coordinates, and 3-D shape of (234) Barbara, using two different shape reconstruction algorithms. By using the lightcurves combined to the results obtained from stellar occultations, we are able to show that the shape of (234) Barbara exhibits large concave areas. Possible links of the shape to the polarimetric properties and the object evolution are discussed. We also show that VLTI data can be modeled without the presence of a satellite.
Earth, Moon, and Planets, 2006
The astronomer's telegram, 2020
Monthly Notices of the Royal Astronomical Society
The recent close approach of comet C/2020 F3 (NEOWISE) allowed us to study the morphology of its ... more The recent close approach of comet C/2020 F3 (NEOWISE) allowed us to study the morphology of its inner coma. From the measurement of the dust ejection velocity on spiral structures expanding around the nucleus, we estimated a mean deprojected expansion velocity Vd = 1.11 ± 0.08 km s−1. Assuming that a new shell formed after every rotation of the comet, a period of 7.8 ± 0.2 h was derived. The spin axis orientation was estimated at RA 210° ± 10°, Dec. +35° ± 10°. The coma morphology appears related to two strong, diametrically opposite emissions located at mid-latitudes on the nucleus. A qualitative modelling of the coma produced consistent results with a wide range of dust sizes (0.80–800 μm), with inversely correlated densities (0.003–3.0 g cm−3). Images taken with Vj and r-Sloan filters showed a greater concentration of dust in the first two shells, and an increasing density of radicals emitting in the B and V band passes from the third shell outwards. Striae-like structures in ...
We report the detection of transits by the 3.1M Jup companion to the V=8.17 G0V star HD 17156. Th... more We report the detection of transits by the 3.1M Jup companion to the V=8.17 G0V star HD 17156. The transit was observed by three independant observers on Sept. 9/10, 2007 (two in central Italy and one in the Canary Islands), who obtained detections at confidence levels of 3.0 σ, 5.3 σ, and 7.9 σ, respectively. The observations were carried out under the auspices of the Transitsearch.org network, which organizes follow-up photometric transit searches of known planet-bearing stars during the time intervals when transits are expected to possibly occur. Analyses of the 7.9 σ data set indicates a transit depth d = 0.0062 ± 0.0004, and a transit duration t = 186 ± 5 min. These values are consistent with the transit of a Jupiter-sized planet with an impact parameter b = a cos i/R ⋆ ∼ 0.8. This planet occupies a unique regime among known transiting extrasolar planets, both as a result of its large orbital eccentricity (e = 0.67) and long orbital period (P = 21.2d). The planet receives a 26-fold variation in insolation during the course of its orbit, which will make it a useful object for characterization of exoplanetary atmospheric dynamics.
Astronomy & Astrophysics
Context. Recent results for asteroid rotation periods from the TESS mission showed how strongly p... more Context. Recent results for asteroid rotation periods from the TESS mission showed how strongly previous studies have underestimated the number of slow rotators, revealing the importance of studying those targets. For most slowly rotating asteroids (those with P > 12 h), no spin and shape model is available because of observation selection effects. This hampers determination of their thermal parameters and accurate sizes. Also, it is still unclear whether signatures of different surface material properties can be seen in thermal inertia determined from mid-infrared thermal flux fitting. Aims. We continue our campaign in minimising selection effects among main belt asteroids. Our targets are slow rotators with low light-curve amplitudes. Our goal is to provide their scaled spin and shape models together with thermal inertia, albedo, and surface roughness to complete the statistics. Methods. Rich multi-apparition datasets of dense light curves are supplemented with data from Kepler...
... M.; Sergeev, A.; Kozlov, V.; Camarasa, J.; Nicolas, J.; Bel, J.; Martignoni, M.; Noel, T.; Br... more ... M.; Sergeev, A.; Kozlov, V.; Camarasa, J.; Nicolas, J.; Bel, J.; Martignoni, M.; Noel, T.; Bryssinck, E.; Soulier, JF; Diepvens, A.; Gao, X.; Hui, M.-T.; Zhao, HB; Yao, JS; Zhaori, GT; Lu, H.; Wang, M.; Hong, RQ; Hu, LF; Xia, Y.; Hills, K.; Takahashi, T.; Camilleri, P.; Baroni, S.; Concari, P ...
Astrophysics and Space Science, 2012
Extensive observations of comet C/2004 Q2 (Machholz) were carried out between August 2004 and May... more Extensive observations of comet C/2004 Q2 (Machholz) were carried out between August 2004 and May 2005. The images obtained were used to investigate the comet"s inner coma features at resolutions between 350 and 1500 km/pixel. A photometric analysis of the dust outflowing from the comet"s nucleus and the study of the motion of the morphological structures in the inner coma indicated that the rotation period of the nucleus was most likely around 0.74 days. A thorough investigation of the inner coma morphology allowed us to observe two main active sources on the comet"s nucleus, at a latitude of +85° ± 5° and +45° ± 5°, respectively. Further sources have been observed, but their activity ran out quite rapidly over time; the most relevant was at lat com. = 25° ± 5°. Graphic simulations of the geometrical conditions of observation of the inner coma were compared with the images and used to determine a pole orientation at RA=95° ± 5°, Dec=+35° ± 5°. The comet"s spin axis was lying nearly on the plane of the sky during the first decade of December 2004.
Monthly Notices of the Royal Astronomical Society: Letters
We processed images taken with the Hubble Space Telescope (HST) to investigate any morphological ... more We processed images taken with the Hubble Space Telescope (HST) to investigate any morphological features in the inner coma suggestive of a peculiar activity on the nucleus of the interstellar comet 2I/Borisov. The coma shows an evident elongation, in the position angle (PA) ∼0○-180○ direction, which appears related to the presence of a jet originating from a single active source on the nucleus. A counterpart of this jet directed towards PA ∼10○ was detected through analysis of the changes of the inner coma morphology on HST images taken in different dates and processed with different filters. These findings indicate that the nucleus is probably rotating with a spin axis projected near the plane of the sky and oriented at PA ∼100○-280○, and that the active source is lying in a near-equatorial position. Subsequent observations of HST allowed us to determine the direction of the spin axis at RA = 17h20m ±15○ and Dec = −35○ ±10○. Photometry of the nucleus on HST images of 12 October 20...
Icarus
We studied a sample of 93 asteroid pairs, i.e., pairs of genetically related asteroids that are o... more We studied a sample of 93 asteroid pairs, i.e., pairs of genetically related asteroids that are on highly similar heliocentric orbits. We estimated times elapsed since separation of pair members (i.e., pair age) that are between 7 × 10 3 yr and a few 10 6 yr. With photometric observations, we derived the rotation periods P 1 for all the primaries (i.e., the larger members of asteroid pairs) and a sample of secondaries (the smaller pair members). We derived the absolute magnitude differences of the studied asteroid pairs that provide their mass ratios q. For a part of the studied pairs, we refined their WISE geometric albedos and collected or estimated their taxonomic classifications. For 17 asteroid pairs, we also determined their pole positions. In two pairs where we obtained the spin poles for both pair components, we saw the same sense of rotation for both components and constrained the angles between their original spin vectors at the time of their separation. We found that the primaries of 13 asteroid pairs in our sample are actually binary or triple systems, i.e., they have one or two bound, orbiting secondaries (satellites). As a by-product, we found also 3 new young asteroid clusters (each of them consisting of three known asteroids on highly similar heliocentric orbits). We compared the obtained asteroid pair data with theoretical predictions and discussed their implications. We found that 86 of the 93 studied asteroid pairs follow the trend of primary rotation period vs mass ratio that was found by Pravec et al. (2010). Of the 7 outliers, 3 appear insignificant (may be due to our uncertain or incomplete knowledge of the three pairs), but 4 are high mass ratio pairs that were unpredicted by the theory of asteroid pair formation by rotational fission. We discuss a (remotely) possible way that they could be created by rotational fission of flattened parent bodies followed by reshaping of the formed components. The 13 asteroid pairs with binary primaries are particularly interesting systems that place important constraints on formation and evolution of asteroid pairs. We present two hypotheses for their formation: The asteroid pairs having both bound and unbound secondaries could be "failed asteroid clusters", or they could be formed by a cascade primary spin fission process. Further studies are needed to reveal which of these two hypotheses for formation of the paired binary systems is real.
Astronomy & Astrophysics
Context. Earlier work suggests that slowly rotating asteroids should have higher thermal inertias... more Context. Earlier work suggests that slowly rotating asteroids should have higher thermal inertias than faster rotators because the heat wave penetrates deeper into the subsurface. However, thermal inertias have been determined mainly for fast rotators due to selection effects in the available photometry used to obtain shape models required for thermophysical modelling (TPM). Aims. Our aims are to mitigate these selection effects by producing shape models of slow rotators, to scale them and compute their thermal inertia with TPM, and to verify whether thermal inertia increases with the rotation period. Methods. To decrease the bias against slow rotators, we conducted a photometric observing campaign of main-belt asteroids with periods longer than 12 h, from multiple stations worldwide, adding in some cases data from WISE and Kepler space telescopes. For spin and shape reconstruction we used the lightcurve inversion method, and to derive thermal inertias we applied a thermophysical mo...
Astronomy & Astrophysics
Context. The available set of spin and shape modelled asteroids is strongly biased against slowly... more Context. The available set of spin and shape modelled asteroids is strongly biased against slowly rotating targets and those with low lightcurve amplitudes. This is due to the observing selection effects. As a consequence, the current picture of asteroid spin axis distribution, rotation rates, radiometric properties, or aspects related to the object’s internal structure might be affected too. Aims. To counteract these selection effects, we are running a photometric campaign of a large sample of main belt asteroids omitted in most previous studies. Using least chi-squared fitting we determined synodic rotation periods and verified previous determinations. When a dataset for a given target was sufficiently large and varied, we performed spin and shape modelling with two different methods to compare their performance. Methods. We used the convex inversion method and the non-convex SAGE algorithm, applied on the same datasets of dense lightcurves. Both methods search for the lowest devi...
Icarus
Eos family was created during a catastrophic impact about 1.3 Gyr ago. Rotation states of individ... more Eos family was created during a catastrophic impact about 1.3 Gyr ago. Rotation states of individual family members contain information about the history of the whole population. We aim to increase the number of asteroid shape models and rotation states within the Eos collision family, as well as to revise previously published shape models from the literature. Such results can be used to constrain theoretical collisional and evolution models of the family, or to estimate other physical parameters by a thermophysical modeling of the thermal infrared data. We use all available disk-integrated optical data (i.e., classical dense-in-time photometry obtained from public databases and through a large collaboration network as well as sparse-in-time individual measurements from a few sky surveys) as input for the convex inversion method, and derive 3D shape models of asteroids together with their rotation periods and orientations of rotation axes. We present updated shape models for 15 asteroids and new shape model determinations for 16 asteroids. Together with the already published models from the publicly available DAMIT database, we compiled a sample of 56 Eos family members with known shape models that we used in our analysis of physical properties within the family. Rotation states of asteroids smaller than ∼20 km are heavily influenced by the YORP effect, whilst the large objects more or less retained their rotation state properties since the family creation. Moreover, we also present a shape model and bulk density of asteroid (423) Diotima, an interloper in the Eos family, based on the disk-resolved data obtained by the Near InfraRed Camera (Nirc2) mounted on the W.M. Keck II telescope.
Many new constellation figures have been proposed over the ages. Not all have been accepted, and ... more Many new constellation figures have been proposed over the ages. Not all have been accepted, and here the authors examine some of the constellations which have not survived.
Federico Manzini report the discovery by Alessandro Dimai, on behalf of the CROSS Program (cf. IA... more Federico Manzini report the discovery by Alessandro Dimai, on behalf of the CROSS Program (cf. IAUC 7373) with the 0.5-m "Ullrich" telescope of the Col Druscié observatory (Cortina d'Ampezzo- Italy), of an apparent supernova in IC 178 at a magnitude of 15.5 about; two unfiltered CCD images taken on 2005 July 15.05 (limiting magnitude about 19.0) shown the new object. The presence of the object with magnitude 15.4 about, is confirmed by other two unfiltered CCD images taken on 2005 July 16.01 (limiting magnitude about 18.5) with the same telescope.
Earth Moon and Planets, 1997
Hundreds of high quality CCD images obtained by the GAT group with the 33.5 cm reflector of the S... more Hundreds of high quality CCD images obtained by the GAT group with the 33.5 cm reflector of the Sozzago Astronomical Observatory (SAS) provide a detailed insight into the temporal evolution of comet Hale-Bopp. The images cover the time period from May 1996 until May 1997 and allowed us to analyze various near nucleus phenomena. Among them are jet structures that
IAUC 8588 available at Central Bureau for Astronomical Telegrams.
The minor planet (1139) Atami showed mutual eclipses features on its light curves during its 2005... more The minor planet (1139) Atami showed mutual eclipses features on its light curves during its 2005 opposition. Photometric and radar analysis reveal the binarity of this system composed by two bodies of the same size (7.4x4.4x4.4 km 15%) separated by about 17.7 1.1 km. Rotations and revolutions are synchronous and the period is T =1.145 0.002 days. From a model, we derived bulk density =2.2 0.5 g/cm3. Spectrometry was performed during an eclipse. It reveals that the two bodies have the same reectance
Monthly Notices of the Royal Astronomical Society, 2015
Asteroid (234) Barbara is the prototype of a category of asteroids that has been shown to be extr... more Asteroid (234) Barbara is the prototype of a category of asteroids that has been shown to be extremely rich in refractory inclusions, the oldest material ever found in the Solar System. It exhibits several peculiar features, most notably its polarimetric behavior. In recent years other objects sharing the same property (collectively known as "Barbarians") have been discovered. Interferometric observations in the mid-infrared with the ESO VLTI suggested that (234) Barbara might have a bi-lobated shape or even a large companion satellite. We use a large set of 57 optical lightcurves acquired between 1979 and 2014, together with the timings of two stellar occultations in 2009, to determine the rotation period, spin-vector coordinates, and 3-D shape of (234) Barbara, using two different shape reconstruction algorithms. By using the lightcurves combined to the results obtained from stellar occultations, we are able to show that the shape of (234) Barbara exhibits large concave areas. Possible links of the shape to the polarimetric properties and the object evolution are discussed. We also show that VLTI data can be modeled without the presence of a satellite.