Utilizando modelos semiempíricos de los espectros de fotoabsorción de varios fullerenos individuales (C_80, C_240, C_320 y C_540) predecimos transiciones en la región de la banda difusa más intensa del medio interestelar a 4430 A que podrían explicar su origen, hasta ahora desconocido. Estos modelos también presentan una alta densidad de transiciones en el ultravioleta que reproducen el denominado "bump" a 2175 A en la curva de extinción del medio interestelar (Iglesias-Groth 2004). Parece que los fullerenos podrían ser responsables de dos de los mayores rasgos de la absorción interestelar. Haciendo uso de las secciones eficaces teóricas y de los datos empíricos estimamos que la abundancia de fullerenos es de 0.05 moléculas por millón de átomos de hidrógeno en regiones del medio interestelar con índice de exceso de color E(B-V)~ 1.0.
Advertised on
It may interest you
-
Only a handful of observations truly constrain the nature of dark matter, which is why dozens of different physical models are still viable. Several of the most popular alternatives predict that dark matter halos slowly “thermalize” over time, gradually changing shape and expanding until they form a central region of nearly constant density -- a core. This transformation would not occur if the dark matter particles were completely collision-less, as assumed in the standard model. Therefore, the presence or absence of such a core provides a powerful way to distinguish between the standardAdvertised on -
We present, for the first time, model spectra of single-age, single-metallicity stellar populations computed with the E-MILES evolutionary synthesis code incorporating an environment-dependent, variable galaxy-wide initial mass function (gwIMF). This gwIMF, calculated using the GalIMF code, is rooted in the integrated galactic initial mass function (IGIMF) theory, which predicts IMF variations as a function of the star formation rate and the metallicity. By coupling these two codes, we generated a comprehensive library of single-burst stellar population spectra uniquely sensitive to gwIMFAdvertised on -
Sub-Neptunes - planets larger than Earth but smaller than Neptune - are the most common type of planet in our Galaxy, yet they are entirely absent from our own Solar System. This absence makes them a major focus for astronomers seeking to understand planetary formation and evolution. We recently conducted an international study, as part of the THIRSTEE project, to characterize two such planets orbiting very similar small, cool stars known as M dwarfs: TOI-521 and TOI-912 . THIRSTEE is an observational-based program that aims to shed light on the sub-Neptune population by providing anAdvertised on