Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>A recent RNAAS, analyzing data from the WASP survey, claimed that the star TYC 2623-1439-1 underwent a 1% dimming that lasted for 11 days, and interpreted this as a transit of a wide-orbiting planet. However, WASP survey data is prone to red noise. I show that the same dip is seen on a nearby star, and conclude that it is a pipeline artifact rather than being real.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Measuring the amount of gas and dust in protoplanetary disks is a key challenge in planet formation studies. Here we provide a new set of dust depletion factors and relative mass surface densities of gas and dust for the innermost regions of a sample of protoplanetary disks. We do this by combining stellar theory with observed refractory element abundances in both disk hosts and open cluster stars. Our results are independent of, and complementary to, those obtained from spatially resolved disk observations.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The analysis of nine high resolution SWP spectra of the chemically peculiar star HR 6000 recorded by the International Ultraviolet Explorer reveals low amplitude variations of the far-ultraviolet flux (about 15% at 1500 Å) over the various observations with IUE. These variations could be caused by horizontal gradients of abundances of chemical elements over the surface of HR 6000.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The temporal variability of the colors of comae of comets has been reported for some decades. The color indices B-R of comets Hale-Bopp and Tabur were estimated with a variation of the model of Kolokolova et al., according to geometrical, populational, and compositional parameters of cometary dust. A principal component analysis of five model parameters points that the variation of these color indices is usually associated with changes in population or geometric parameters, and their extremes with a compositional variation of the dust grains.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The analysis of twenty-four high resolution SWP spectra of the magnetic Bp star HD 79158 (36 Lynxis) recorded by the International Ultraviolet Explorer (IUE) reveals that the far-ultraviolet flux of this star mostly remained constant over the various observations with IUE. Only a few spectra show less flux shortwards of 1600 Å and enhanced line absorption compared to the mean spectrum, which could be interpreted as non uniform distribution of certain chemical elements over the surface of 36 Lynxis. The TESS lightcurve of HD 79158 reveals a complex structure with an estimated rotational period of about 3.832 ± 0.019 days, close to previous determinations.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The OMNI data set is a tool well situated for analysis with advanced machine learning (ML) and artificial intelligence (AI) techniques. Because OMNI incorporates data from multiple instruments and spacecraft, care must be taken when interpreting these results. We discuss the OMNI/Lo plasma data sources and one potential challenge with interpreting the results of ML and AI techniques when applied to it.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Charting the near-future motion of known stars through the galaxy, none will pass closer to the Sun than Gliese 710. Here, we present an updated analysis of this upcoming flyby using Gaia DR3 data as well as the latest planetary ephemerides. Our new estimate reproduces the nominal values of those already published, but with reduced associated uncertainties. The distribution of distances of closest approach has a median value of 0.052 pc with a 90% probability of coming within 0.048–0.056 pc of the Sun; the associated time of perihelion passage is determined to be between 1.26 and 1.33 Myr with 90% confidence, with a most likely value of 1.29 Myr.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Light escaping from a gravitational potential suffers a redshift with magnitude proportional to the depth of the potential. This “gravitational redshift” is easily measurable in dense stars such as white dwarfs, but is much weaker and has evaded unambiguous detection in main-sequence stars. I show that the effect is directly measurable in the Gaia DR3 radial velocities (RVs) of the components of wide binary stars. In a sample of ∼500 wide binaries containing a solar-type main-sequence star and a red giant or red clump companion, the apparent RV of the giant is on average 0.49 ± 0.02 km s<jats:sup>−1</jats:sup> lower than that of the main-sequence star. This owes primarily to the giants’ weaker gravitational fields and is in reasonably good agreement with the value expected from general relativity.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We have searched 14 dense cores, 11 of which have literature distances of 150–350 pc, for T Tauri stars by using the Wide Field Grism Spectrograph 2 on the University of Hawaii 2.2 m telescope. As a result, we detected 50 H<jats:italic>α</jats:italic> emission stars including 24 newly found objects. Twelve out of these 50 stars have a distance of ∼190–370 pc, and 16 of them are within a distance of ∼460 pc. Seven of these 16 objects are newly found H<jats:italic>α</jats:italic> emission stars and would serve as new good targets for studying protoplanetary disks and young exoplanets.</jats:p>