Año de inicio
1986
Unidad organizativa
Institución organizadora
Subvenciones relacionadas:
General
Descripción
Las estrellas de masa baja e intermedia (M < 8 masas solares, Ms) representan la mayoría de estrellas en el Cosmos y terminan sus vidas en la Rama Asintótica de las Gigantes (AGB) - justo antes de formar Nebulosas Planetarias (NPs) - cuando experimentan procesos nucleosintéticos y moleculares complejos. Las estrellas AGB son importantes contribuyentes al enriquecimiento del medio interestelar, donde nacen nuevas estrellas y planetas (incluyendo nuestro propio Sistema Solar Temprano, SST) y a la evolución química de sistemas estelares como cúmulos globulares (CGs) y galaxias. En particular, las AGBs más masivas (M > 4-5 Ms) sintetizan (radio)isótopos muy diferentes de los formados por AGBs menos masivas y explosiones de Supernova debido a los diferentes mecanismos de nucleosíntesis. Las estrellas evolucionadas en la fase de transición entre AGBs y NPs también forman diversos compuestos orgánicos como PAHs y nanoestructuras moleculares de fullereno y grafeno, siendo un maravilloso laboratorio Astroquímico. Colaboraciones astronómicas punteras como SDSS-IV/APOGEE-2 y el próximo telescopio espacial James Webb representan un paso fundamental para entender la nucleosíntesis y los procesos moleculares en estrellas evolucionadas. Se pretende explorar la nucleosíntesis de (radio)isótopos ligeros/pesados en estrellas AGB y como éstas contribuyen a la radioactividad del SST así como a la formación/evolución de CGs y galaxias. También se pretende entender el proceso de formación "top-down" de nanoestructuras moleculares de fullereno y grafeno en estrellas evolucionadas. Finalmente, se pretende realizar minería de datos obtenidos con el satélite Gaia, para estudiar la fase evolutiva AGB-NP, y además utilizar el telescopio espacial GALEX para descubrir estrellas binarias en NPs Galácticas.
Miembros
Investigador principal
Domingo Aníbal
García Hernández
Personal del proyecto
Arturo
Manchado Torres
Thomas
Masseron
Olga María
Zamora Sánchez
LUCIO
CRIVELLARI
Colaboradores
Dr.
P. García Lario
Dr.
G. García Segura
Dr.
L. Stanghellini
Dr.
E. Villaver
Carlos
Allende Prieto
Jorge
García Rojas
Dr.
B. Plez
Dr.
A. Karakas
Dr.
M. Lugaro
Dr.
D. Lambert
Dr.
P. Ventura
Dr.
F. Cataldo
Dr.
Andres Yague
Dr.
Sun Kwok
Dr.
R. Szczerba
Dr.
J.M. Trigo Rodríguez
Dr.
K. Rao
S. Sadjadi
M. Manteiga
C. Dafonte
R. Santoveña
L. Bianchi
Sz. Mészáros
S. Cristallo
L. Piersanti
Resultados
1. Durante 2020, se han publicado 37 artículos en revistas astronómicas internacionales con referee de alto impacto (incluyendo un review invitado), así como 2 artículos en la revista de Química-Física FNCN.
2. Se han descubierto, por primera vez, estrellas muy ricas en fósforo y cuyo patrón químico no es predicho por ninguna teoría actual de nucleosíntesis estelar.
3. Se ha demostrado que las estrellas ricas en fósforo representan un nuevo sitio estelar para la formación de elementos muy pesados, con importantes implicaciones para la evolución química de nuestra Galaxia.
Actividad científica
Publicaciones relacionadas
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Hot bottom burning and s-process nucleosynthesis in massive AGB stars at the beginning of the thermally-pulsing phaseWe report the first spectroscopic identification of massive Galactic asymptotic giant branch (AGB) stars at the beginning of the thermal pulse (TP) phase. These stars are the most Li-rich massive AGBs found to date, super Li-rich AGBs with log ɛ (Li) ~ 3-4. The high Li overabundances are accompanied by weak or no s-process element (i.e. Rb and Zr)García-Hernández, D. A. et al.
Fecha de publicación:
72013 -
The changing nebula around the hot R Coronae Borealis star DY CentauriAmong the distinguishing characteristics of the remarkable hot R Coronae Borealis star DY Centauri, which was recently found to be a spectroscopic binary, is the presence of nebular forbidden lines in its optical spectrum. A compilation of photometry from 1970 to the present suggests that the star has evolved to higher effective temperatures. AKameswara Rao, N. et al.
Fecha de publicación:
52013 -
Photolytic Decomposition of Hydrogenated C70: C70H38 and C70D38The hydrogenated C70 fullerenes C70H38 and C70D38 have been photolyzed at 245nm under Ar or He flow. The photolysis rate constant have been measured: k = 1.54x10-3s-1 for C70H38, and the photolysis of C70D38 occurs at a rate of 1.17x10-3s-1. A remarkable isotope effect in the photolysis of the two molecules has been determined kH/kD = 1.32. TheManchado, A. et al.
Fecha de publicación:
32009Número de citas0 -
Kinetic Isotope Effects on the Photolysis of C60H18 and C60D18Fullerane C60H18 and its deuterated analogous C60D18 were synthesized in n-hexane solution by a reduction reaction of C60 under the action of HCl or DCl on Zn dust. The resulting solutions were subjected to UV irradiation at 245nm from a low pressure mercury lamp under He. It was found that at 212nm the photolysis rate constant of C60H18 moleculeManchado, A. et al.
Fecha de publicación:
32009Número de citas0 -
Perdeuterofulleranes: Synthesis and Properties of C70D38 and C70H38Perdeutero[70]fullerane, C70D38 and the hydrogenated analogous C70H38 have been synthesized using nascent deuterium or hydrogen generated by the action of DCl or HCl on Zn dust in toluene or benzene solvents. The FT-IR spectra of C70D38 and C70H38 have been studied. A better oxidation stability of C70D38 has been observed by FT-IR spectroscopy inManchado, A. et al.
Fecha de publicación:
32009Número de citas0 -
Synthesis and FT-IR Spectroscopy of Perdeuterofullerane: C60D36 Evidences of Isotope Effect in the Stability of C60D36Perdeuterofullerane, C60D36 was synthesized in toluene solution from DCl and Zn. The FT-IR spectrum of C60D36 was compared with that of C60H36, and the C-H stretching and bending shift due to deuteration was measured so that H/ D = 1.36. The thermal stability of C60D36 was studied under N2 by thermogravimetric and differential thermal analysis. ItManchado, A. et al.
Fecha de publicación:
32009Número de citas0 -
Low and High Temperature Infrared Spectroscopy of C60 and C70 FullerenesThe FT-IR spectra of the fullerenes C60 and C70 have been recorded in the temperature range between 523 K (+250 degrees C) and 93 K (-180 degrees C). As a general rule, it has been observed a shift of the infrared absorption bands toward higher frequencies at lower temperatures. As expected, at 93 K the infrared spectra appear better resolved withManchado, A. et al.
Fecha de publicación:
32010Número de citas0 -
A Simple Synthesis of C60H18 from C60 Fullerene and Hydrogen IodideC60 fullerene can be easily hydrogenated in aromatic solvent under mild conditions with aqueous hydrogen iodide (HI). The resulting black product has the molecular formula C60H24 center dot 2I2 on the basis of the FT-IR spectroscopy and of the thermogravimetric analysis. When this compound is heated under N2 it releases I2 and HI producingIglesias-Groth, S. et al.
Fecha de publicación:
32010Número de citas0 -
Characterization of Hydrogenated Fullerene Mixture of C60Hx and C70HxA commercially available hydrogenated mixture of fullerenes (HMF) composed of 77% C60Hx and 22% C70Hx has been analyzed by liquid chromatographic analysis (HPLC), electronic absorption, FT-IR spectroscopy, solubility and by thermal analysis (TGA). The results confirm that the HMF is composed by a mixture of C60Hx and C70Hx with a high degree ofIglesias-Groth, S. et al.
Fecha de publicación:
32010Número de citas0 -
Determination of the Integrated Molar Absorptivity and Molar Extinction Coefficient of Hydrogenated FullerenesThe integrated molar absorptivity (Psi) and the molar extinction coefficient (epsilon) of each infrared transition of the hydrogenated fullerenes (known as fulleranes) C60H36, C70H38 and a mixture of fulleranes generally referred as 77% of C60Hx and 22% C70Hy with x approximate to y > 30 were determined. These data are useful for the searchManchado, A. et al.
Fecha de publicación:
02013Número de citas0 -
On the Radical Anion Spectra of Fullerenes C-60 and C-70The radical anion spectra of C-60 and C-70 can be easily generated and studied in primary aliphatic amines. In these conditions the C-60-center dot and C-70-center dot species are accompanied by the dianions C-60(2-) and C-70(2-). In the near infrared region the electronic transitions at 1075, 1058 and 991 nm were assigned to C-60-center dot whileManchado, A. et al.
Fecha de publicación:
02013Número de citas0 -
Far- and mid-infrared spectroscopy of complex organic matter of astrochemical interest: coal, heavy petroleum fractions and asphaltenesThe coexistence of a large variety of molecular species (i.e. aromatic, cycloaliphatic and aliphatic) in several astrophysical environments suggests that unidentified infrared emission (UIE) occurs from small solid particles containing a mix of aromatic and aliphatic structures (e.g. coal, petroleum, etc.), renewing the astronomical interest onManchado, A. et al.
Fecha de publicación:
32013 -
Diffuse interstellar bands in fullerene planetary nebulae: the fullerenes - diffuse interstellar bands connectionWe present high-resolution (R ~ 15 000) VLT/UVES optical spectra of two planetary nebulae (PNe; Tc 1 and M 1-20) where C60 (and C70) fullerenes have already been found. These spectra are of high quality (S/N > 300) for PN Tc 1, which permits us to search for the expected electronic transitions of neutral C60 and diffuse interstellar bands (DIBs)García-Hernández, D. A. et al.
Fecha de publicación:
22013 -
Synthesis of polyphenylacetylene by radiation-induced polymerization in deoxycholic acid clathratePhenylacetylene was polymerized as inclusion compound (clathrate) inside deoxycholic acid (DOCA) crystals. The polymerization was initiated by γ radiation and a total dose of 320 kGy was employed. The resulting polyphenylacetylene (PPA) was isolated by dissolution of deoxycholic acid in boiling ethanol. PPA high polymer was accompanied by a seriesIglesias-Groth, S. et al.
Fecha de publicación:
42009 -
Short-lived radioactivity in the early solar system: The Super-AGB star hypothesisThe composition of the most primitive solar system condensates, such as calcium-aluminum-rich inclusions (CAIs) and micron-sized corundum grains, show that short-lived radionuclides (SLR), e.g., 26Al, were present in the early solar system. Their abundances require a local or stellar origin, which, however, is far from being understood. We presentLugaro, Maria et al.
Fecha de publicación:
92012 -
High-resolution Optical Spectroscopy of DY Cen: Diffuse Interstellar Bands in a Proto-fullerene Circumstellar Environment?We search high-resolution and high-quality VLT/UVES optical spectra of the hot R Coronae Borealis star DY Cen for electronic transitions of the C60 molecule and diffuse interstellar bands (DIBs). We report the non-detection of the strongest C60 electronic transitions (e.g., those at ~3760, 3980, and 4024 Å). The absence of C60 absorption bands mayGarcía-Hernández, D. A. et al.
Fecha de publicación:
112012 -
The Hot R Coronae Borealis Star DY Centauri is a BinaryThe remarkable hot R Coronae Borealis (RCB) star DY Cen is revealed to be the first and only binary system to be found among the RCB stars and their likely relatives, including the extreme helium stars and the hydrogen-deficient carbon stars. Radial velocity determinations from 1982 to 2010 have shown that DY Cen is a single-lined spectroscopicKameswara Rao, N. et al.
Fecha de publicación:
112012 -
Infrared Study of Fullerene Planetary NebulaeWe present a study of 16 planetary nebulae (PNe) where fullerenes have been detected in their Spitzer Space Telescope spectra. This large sample of objects offers a unique opportunity to test conditions of fullerene formation and survival under different metallicity environments because we are analyzing five sources in our own Galaxy, four in theGarcía-Hernández, D. A. et al.
Fecha de publicación:
122012 -
The mixed chemistry phenomenon in Galactic Bulge PNeAims: We investigate the dual-dust chemistry phenomenon in planetary nebulae (PNe) and discuss reasons for its occurrence, by analyzing Spitzer/IRS spectra of a sample of 40 Galactic PNe among which 26 belong to the Galactic Bulge (GB). Methods: The mixed chemistry is derived from the simultaneous detection of Polycyclic Aromatic Hydrocarbon (PAH)Perea-Calderón, J. V. et al.
Fecha de publicación:
22009 -
Rubidium, zirconium, and lithium production in intermediate-mass asymptotic giant branch starsContext. A recent survey of a large sample of Galactic intermediate-mass (>3 M&sun;) asymptotic giant branch (AGB) stars shows that they exhibit large overabundances of rubidium (Rb) up to 100-1000 times solar. In contrast, zirconium (Zr) is not enriched in these stars compared to its solar abundances. These observations set constraints on ourvan Raai, M. A. et al.
Fecha de publicación:
42012
