Conferences organized

Main research lines are associated with Ultraviolet Astronomy, Astrophysical Plasmas and Star Formation. These activities are coordinated through the Space Astronomy Research Group at UCM: AEGORA, were a full list of activities and publications is included.

Two recent research works are :

Accretion and Intercycle Variations in the PMS Interacting Binary AK Sco.
Gómez de Castro, A.I., Vallejo, J.C., Canet, Ada, Loyd, Parke, France, Kevin
ABSTRACT:
There are only a handful of known short-period pre-main-sequence spectroscopic binaries with significant accretion rates (Class II sources). AK Sco stands out in this list because the system is composed of two equal mass F5 stars in a highly eccentric orbit thus both stars get as close as 11 stellar radii at periastron passage. This configuration is optimal for accretion studies because enhanced accretion events can be precisely timed at periastron passage. In this work, we present the results from the monitoring of the AK Sco system with Hubble during three consecutive periastron passages. These data provide a unique data set to spectroscopically characterize accretion and evaluate the intercycle variability of the system. Clear evidence of accretion rate enhancement was observed in cycles 1 and 3: the blueing of the near-UV continuum, the sudden flux increase of important accretion tracers, such as the N V, Si IV, and C IV lines, and also of neutral/singly ionized species such as O I and C II. Also, variations in the Si III]/C III] ratio reveal an enhancement of the electron density by an order of magnitude during the periastron passage. Moreover, in cycle 3, the spectral resolution of the observations obtained with the Cosmic Origins Spectrograph enabled us to discern that the flow was channeled preferentially into one of the two components. The most remarkable feature in the cycle-to-cycle variations was the detection of a notable increase of the UV flux from cycle 1 to cycle 2 that was not accompanied by enhanced accretion signatures.

Constraints for Use of Ultraviolet Spectropolarimetry to Detect Chiral Amino Acids from Comets
Gómez de Castro, A.I., de Isidro-Gómez, A.I.
ABSTRACT:
Life is pervasive on planet Earth, but whether life is ubiquitous in the Galaxy and sustainable over timescales comparable to stellar evolution is unknown. Evidence suggests that life first appeared on Earth more than 3.77 Gyr ago, during a period of heavy meteoric bombardment. Amino acids, the building blocks of proteins, have been demonstrated to exist in interstellar ice. As such, the contribution of space-generated amino acids to those existing on Earth should be considered. However, detection of space amino acids is challenging. In this study, we used analytical data from several meteorites and in situ measurements of the comet 67P/Churyumov-Gerasimenko collected by the Rosetta probe to evaluate the detectability of alanine by ultraviolet spectropolarimetry. Alanine is the second-most abundant amino acid after glycine and is optically active. This chirality produces a unique signature that enables reliable identification of this amino acid using the imprint of optical rotatory dispersion (ORD) and circular dichroism (CD) in the ultraviolet spectrum (130-230 nm). Here, we show that the ORD signature could be detected in comets by using ultraviolet spectropolarimetric observations conducted at middle size space observatories. These observations can also provide crucial information for the study of sources of enantiomeric imbalance on Earth.