788 research outputs found
Data Reduction and Control Software for Meteor Observing Stations Based on CCD Video Systems
The SPanish Meteor Network (SPMN) is performing a continuous monitoring of meteor activity over Spain and neighbouring countries. The huge amount of data obtained by the 25 video observing stations that this network is currently operating made it necessary to develop new software packages to accomplish some tasks, such as data reduction and remote operation of autonomous systems based on high-sensitivity CCD video devices. The main characteristics of this software are described here
The Trajectory, Orbit and Preliminary Fall Data of the JUNE BOOTID Superbolide of July 23, 2008
The results of the atmospheric trajectory, radiant, orbit and preliminary fall data calculations of an extremely bright slow-moving fireball are presented. The fireball had a -20.7 maximum absolute magnitude and the spectacular long-persistence dust trail (Fig 1 and 2) was observed in a widespread region of Tajikistan twenty eight minutes after sunset, precisely at 14h 45m 25s UT on July 23, 2008. The bolide was first recorded at a height of 38.2 km, and attained its maximum brightness at a height of 35.0 km and finished at a height of 19.6 km. These values are very much in line with other well-known fireballs producing meteorites. The first break-up must have occurred under an aerodynamic pressure Pdyn of about 1.5 MPa, similar to those derived from the study of atmospheric break-ups of previously reported meteorite-dropping bolides. Our trajectory, and dynamic results suggest that one might well expect to find meteorites on the ground in this case. The heliocentric orbit of the meteoroid determined from the observations is very similar to the mean orbit of the June Bootid meteor shower, whose parental comet is 7P/Pons-Winnecke (Lindblad et al. 2003). If the parent was indeed a comet, this has implications for the internal structure of comets, and for the survivability of cometary meteorites
The 2011 October Draconids Outburst. II. Meteoroid Chemical Abundances from Fireball Spectroscopy
On October 8, 2011 the Earth crossed dust trails ejected from comet
21P/Giacobini-Zinner in the late 19th and early 20th Century. This gave rise to
an outburst in the activity of the October Draconid meteor shower, and an
international team was organized to analyze this event. The SPanish Meteor
Network (SPMN) joined this initiative and recorded the October Draconids by
means of low light level CCD cameras. In addition, spectroscopic observations
were carried out. Tens of multi-station meteor trails were recorded, including
an extraordinarily bright October Draconid fireball (absolute mag. -10.5) that
was simultaneously imaged from three SPMN meteor ob-serving stations located in
Andalusia. Its spectrum was obtained, showing a clear evolution in the relative
intensity of emission lines as the fireball penetrated deeper into the
atmosphere. Here we focus on the analysis of this remarkable spectrum, but also
discuss the atmospheric trajectory, atmospheric penetration, and orbital data
computed for this bolide which was probably released during
21P/Giacobini-Zinner return to perihelion in 1907. The spectrum is discussed
together with the tensile strength for the October Draconid meteoroids. The
chemical profile evolution of the main rocky elements for this extremely bright
bolide is compared with the elemental abundances obtained for 5 October
Draconid fireballs also recorded during our spectroscopic campaign but observed
only at a single station. Significant chemical heterogeneity between the small
meteoroids is found as we should expect for cometary aggregates being formed by
diverse dust components.Comment: Manuscript in press in Monthly Notices of the Royal Astronomical
Society. Accepted for publication in MNRAS on April 28th, 2013 Manuscript
Pages: 28 Tables: 5 Figures: 12. Manuscript associated: "The 2011 October
Draconids outburst. I. Orbital elements, meteoroid fluxes and
21P/Giacobini-Zinner delivered mass to Earth" by Trigo-Rodriguez et al. is
also in press in the same journa
The Effect of Aqueous Alteration in Antarctic Carbonaceous Chondrites from Comparative ICP-MS Bulk Chemistry
Terrestrial ages of Antarctic carbonaceous chondrites (CC) indicate that these meteorites have been preserved in or on ice for, at least, tens of thousands of years. Due to the porous structure of these chondrites formed by the aggregation of silicate-rich chondrules, refractory inclusions, metal grains, and fine-grained matrix materials, the effect of pervasive terrestrial water is relevant. Our community defends that pristine CC matrices are representing samples of scarcely processed protoplanetary disk materials as they contain stellar grains, but they might also trace parent body processes. It is important to study the effects of terrestrial aqueous alteration in promoting bulk chemistry changes, and creating distinctive alteration minerals. Particularly because it is thought that aqueous alteration has particularly played a key role in some CC groups in modifying primordial bulk chemistry, and homogenizing the isotopic content of fine-grained matrix materials. Fortunately, the mineralogy produced by parent-body and terrestrial aqueous alteration processes is distinctive. With the goal to learn more about terrestrial alteration in Antarctica we are obtaining reflectance spectra of CCs, but also performing ICP-MS bulk chemistry of the different CC groups. A direct comparison with the mean bulk elemental composition of recovered falls might inform us on the effects of terrestrial alteration in finds. With such a goal, in the current work we have analyzed some members representative of CO and CM chondrite groups
Rubidium-Rich Asymptotic Giant Branch Stars
A long debated issue concerning the nucleosynthesis of neutron-rich elements in Asymptotic Giant Branch (AGB) stars is the identification of the neutron source. We report intermediate-mass (4 to 8 solar masses) AGB stars in our Galaxy that are rubidium-rich owing to overproduction of the long-lived radioactive isotope 87Rb, as predicted theoretically 40 years ago. This represents a direct observational evidence that the 22Ne(alpha,n)25Mg reaction must be the dominant neutron source in these stars. These stars then challenge our understanding of the late stages of the evolution of intermediate-mass stars and would promote a highly variable Rb/Sr environment in the early solar nebula
Spectroscopy and Orbital Analysis of Bright Bolides Observed over the Iberian Peninsula from 2010 to 2012
We present the analysis of the atmospheric trajectory and orbital data of
four bright bolides observed over Spain, one of which is a potential meteorite
dropping event. Their absolute magnitude ranges from -10 to -11. Two of these
are of sporadic origin, although a Geminid and a kappa-Cygnid fireball are also
considered. These events were recorded in the framework of the continuous
fireball monitoring and spectroscopy campaigns developed by the SPanish Meteor
Network (SPMN) between 2010 and 2012. The tensile strength of the parent
meteoroids is estimated and the abundances of the main rock-forming elements in
these particles are calculated from the emission spectrum obtained for three of
these events. This analysis revealed a chondritic nature for these meteoroids.Comment: Manuscript in press in Monthly Notices of the Royal Astronomical
Societ
Application of an Equilibrium Vaporization Model to the Ablation of Chondritic and Achondritic Meteoroids
We modeled equilibrium vaporization of chondritic and achondritic materials
using the MAGMA code. We calculated both instantaneous and integrated element
abundances of Na, Mg, Ca, Al, Fe, Si, Ti, and K in chondritic and achondritic
meteors. Our results are qualitatively consistent with observations of meteor
spectra.Comment: 8 pages, 4 figures; in press, Earth, Moon, and Planets, Meteoroids
2004 conference proceeding
MAXI J1659-152: the shortest orbital period black-hole binary
Following the detection of a bright new X-ray source, MAXI J1659-152, a
series of observations was triggered with almost all currently flying
high-energy missions. We report here on XMM-Newton, INTEGRAL and RXTE
observations during the early phase of the X-ray outburst of this transient
black-hole candidate. We confirm the dipping nature in the X-ray light curves.
We find that the dips recur on a period of 2.4139+/-0.0005 hrs, and interpret
this as the orbital period of the system. It is thus the shortest period
black-hole X-ray binary known to date. Using the various observables, we derive
the properties of the source. The inclination of the accretion disk with
respect to the line of sight is estimated to be 60-75 degrees. The companion
star to the black hole is possibly a M5 dwarf star, with a mass and radius of
about 0.15 M_sun and 0.23 R_sun, respectively. The system is rather compact
(orbital separation is about 1.35 R_sun) and is located at a distance of
roughly 7 kpc. In quiescence, MAXI J1659-152 is expected to be optically faint,
about 28 mag in the V-band.Comment: 5 pages, 4 figures, to be published in the proceedings of the 4th
International MAXI Workshop `The First Year of MAXI: Monitoring variable
X-ray sources', 2010 Nov 30 - Dec 2, Tokyo, Japa
- …