José M. Madiedo

A Pluto-like radius and a high albedo for the dwarf planet Eris from an occultation

The dwarf planet Eris is a trans-Neptunian object with an orbital eccentricity of 0.44, an inclination of 44 degrees and a surface composition very similar to that of Pluto. It resides at present at 95.7 astronomical units (1u2009au is the Earth-Sun distance) from Earth, near its aphelion and more than three times farther than Pluto. Owing to this great distance, measuring its size or detecting a putative atmosphere is difficult. Here we report the observation of a multi-chord stellar occultation by Eris on 6 November 2010 ut. The event is consistent with a spherical shape for Eris, with radius 1,163u2009±u20096u2009kilometres, density 2.52u2009±u20090.05 grams per cm3 and a high visible geometric albedo, . No nitrogen, argon or methane atmospheres are detected with surface pressure larger than ∼1u2009nanobar, about 10,000 times more tenuous than Plutos present atmosphere. As Plutos radius is estimated to be between 1,150 and 1,200 kilometres, Eris appears as a Pluto twin, with a bright surface possibly caused by a collapsed atmosphere, owing to its cold environment. We anticipate that this atmosphere may periodically sublimate as Eris approaches its perihelion, at 37.8 astronomical units from the Sun.

Robotic Systems for Meteor Observing and Moon Impact Flashes Detection in Spain

A robotic observatory has been setup in the south-west of Spain with the aim to study meteoroids interacting with the Earths atmosphere and meteoroids impacting on the Moons surface. This is achieved by using an array of high-sensitivity CCD video cameras and three automated Schmidt-Cassegrain telescopes. We summarize here the main characteristics of this new facility.

Analysis of a superbolide from a Damocloid observed over Spain on July 13, 2012

A superbolide with an estimated absolute magnitude of -20+-1 was seen on July 13, 2012 over the center and south of Spain. This extraordinary event, which was witnessed by numerous casual observers, was recorded in the framework of the continuous fireball monitoring and meteor spectroscopy campaign performed by the SPanish Meteor Network (SPMN). Thus, because of optimal weather conditions, the bolide was imaged from ten meteor observing stations. Here we present the analysis of this magnificent event, which is the brightest fireball ever recorded by our team. The atmospheric trajectory of the bolide and the orbit in the Solar System of the parent meteoroid were obtained. The emission spectrum produced during the ablation of this particle is also discussed. We found that the meteoroid, which was following a Halley Type Comet orbit, was depleted in Na and had a tensile strength one order of magnitude higher than that corresponding to typical cometary materials. By means of orbital analysis tools we have investigated the likely parent body of this particle and the results suggest that the progenitor is a damocloid. The impact area of the hypothetical remnants of the meteoroid is also given and a search for meteorites was performed, but none were found.

Analysis of the September ε-Perseid outburst in 2013

We acknowledge support from the Spanish Ministry of Science and Innovation (projects nAYA2015-68646-P and AYA 2015-67175-P).

First determination of the temperature of a lunar impact flash and its evolution

The authors acknowledge support from projects AYA2014-61357-EXP (MINECO), AYA2015-68646-P (MINECO/FEDER), Proyecto de Excelencia de la Junta de Andalucia, J.A. 2012-FQM1776, and from FEDER.

THE 2016 QUADRANTIDS BALLOON-BORNE MISSION OVER SPAIN: FULL HD AND COLOUR VIDEORECORDING.

VIDEORECORDING. A. Sanchez de Miguel 1 , F. Ocana 1 , C.E. Tapia Ayuga 1 , J.M. Madiedo 2,3 , J. Zamorano 1 , J. Izquierdo 1 , M. A. Gomez Sanchez-Tirado 4 , F. Ortuno 4 , D. Mayo 4 , R. Raya 4 , A. Conde 4 and P. Leon 4 . 1 Dpto. de Astrofisica y CC. de la Atmosfera, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, 28040 Madrid, Spain, alejasan@ucm.es, 2 Facultad de Ciencias Experimentales, Universidad de Huelva, 21071 Huelva, Spain, madiedo@uhu.es, 3 Dpto. de Fisica Atomica, Molecular y Nuclear, Facultad de Fisica, Universidad de Sevilla, 41012 Sevilla, Spain, 4 Proyecto Daedalus – Asociacion AstroINNOVA, C/Poeta Mohammed Iqbal, 6 1o4, 14010 Cordoba, Spain, astroinnova@astroinnova.org.