Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>We investigate the evolution of the physical extent of star formation of <jats:italic>M</jats:italic> <jats:sub>⋆</jats:sub> &gt; 10<jats:sup>9</jats:sup>  <jats:italic>M</jats:italic> <jats:sub>⊙</jats:sub> rapidly quenching galaxies at <jats:italic>z</jats:italic> = 1.0–1.4. We measure the galaxy H<jats:italic>α</jats:italic> and stellar continuum sizes from their HST/WFC3 G141 grism spectroscopy and connect the galaxy sizes to time on their evolutionary delayed–<jats:italic>τ</jats:italic> tracks determined in Noirot et al. Most galaxies (10/13) have non-evolving H<jats:italic>α</jats:italic>-to-continuum size-ratios consistent with unity within the measurement uncertainties, suggesting an homogeneous decline of star formation in these galaxies despite a rapid shut-down of their star formation. On the other hand, a handful (3/13) show statistically smaller H<jats:italic>α</jats:italic> sizes compared to the stellar continuum as they age and approach the blue-cloud/red-sequence transition region. This suggests an outside-in shut-down of the star formation (potentially driven by environmental mechanisms) in these rapidly evolving galaxies as they move from the blue cloud toward the red sequence.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present medium-resolution (<jats:italic>λ</jats:italic>/Δ<jats:italic>λ</jats:italic> = 2700), near-infrared spectral standards for field L0–L2, L4, and L7–Y0 dwarfs obtained with the Near-Infrared Echellette Spectrometer on the Keck II 10 m telescope. These standards allow for detailed spectral comparative analysis of cold brown dwarfs discovered through ongoing ground-based projects such as Backyard Worlds: Planet 9, and forthcoming space-based spectral surveys such as the James Webb Space Telescope, SPHEREx, Euclid, and the Nancy Grace Roman Space Telescope.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The radiative transfer model makes it possible to establish relationships between the single scattering albedo and the integral albedo of a medium consisting of particles. In this paper, an approximation is proposed for solving the inverse problem—calculating the albedo of a single scattering of a particle, based on the known value of the integral albedo. This approximation can be useful to all researchers involved in the photometry of solar system bodies with regolith-like surfaces.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The analysis of 18 high resolution spectra of the chemically peculiar star HR 1079 recorded by the International Ultraviolet Explorer reveals large amplitude variations of the far ultraviolet flux (about 80% flux decrease at minimum compared to maximum) over the various observations with IUE. These variations could reflect the presence of spots over the surface of HD 21933. The TESS lightcurve of HD 21933 has a complex structure which resembles a double sine structure. The time intervals separating successive minima are not constant but range from 1.16 to 1.32 ± 0.03 days.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Using a data-driven machine learning tool we report <jats:italic>T</jats:italic> <jats:sub>eff</jats:sub>, <jats:inline-formula> <jats:tex-math> <?CDATA $\mathrm{log}(g)$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>log</mml:mi> <mml:mo stretchy="true">(</mml:mo> <mml:mi>g</mml:mi> <mml:mo stretchy="true">)</mml:mo> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="rnaasac8676ieqn1.gif" xlink:type="simple" /> </jats:inline-formula>, <jats:inline-formula> <jats:tex-math> <?CDATA $v\sin (i)$?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>v</mml:mi> <mml:mi>sin</mml:mi> <mml:mo stretchy="true">(</mml:mo> <mml:mi>i</mml:mi> <mml:mo stretchy="true">)</mml:mo> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="rnaasac8676ieqn2.gif" xlink:type="simple" /> </jats:inline-formula>, and elemental abundances for 15 elements (C, N, O, Na, Mg, Al, Si, Ca, Ti, V, Cr, Mn, Fe, Ni, Y) for a sample of 25 exoplanet host stars targeted by JWST's first year of observations. The chemical diversity of these stars show that, while a number of their companion planets may have formed in a disk with chemistry similar to Solar, some JWST targets likely experienced different disk compositions. This sample is part of a larger forthcoming catalog that will report homogeneous abundances of ∼4500 FGK stars derived from Keck/HIRES optical spectra.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Dynamical interactions facilitated by the high densities in massive star clusters can lead to large numbers of stellar collisions and unique stellar evolution pathways not possible for stars evolving in isolation. Using <jats:italic>N</jats:italic>-body cluster models, we study the role of stellar collisions in the formation of massive black holes, specifically studying the effect of stellar metallicity on this process. We show that at high metallicity (up to solar), the number of massive black holes formed may be reduced by up to a factor of ten compared to low-metallicity clusters. We also examine the role of collisions in the production of pair-instability supernovae and predict event rates of these transients in the local universe.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The degree of linear polarization of the main-belt asteroid 47 Aglaja was measured at low phase angles. The data obtained made it possible to construct a complete branch of the negative polarization. Comparison with asteroids of the same spectral type and having equally high albedo values showed that asteroid 47 Aglaja has a much smaller negative polarization branch, which indicates a possible difference in the chemical composition or structure of matter on the surface.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The Symbiotic Mira HM Sge has dimmed considerably over the last year, beyond what is expected of its pulsation-related variability. HM Sge is composed of a cool oxygen-rich AGB star accreting onto a hotter white dwarf companion. The system brightened 6 mag in the optical in 1975 as a result of a Nova-like outburst. It has since dimmed and plateaued in the visible, while gradually growing in brightness in the near-IR over the past 15 yr (0.092 mag yr<jats:sup>−1</jats:sup>). Within the last year, however, the brightness has dropped by 1.52 mag in the <jats:italic>I</jats:italic>-band. While the system is expected to be near its pulsation minimum, the brightness is below the values expected of the last three pulsation cycles, and appears independent of the system’s fundamental mode pulsations. We suspect this may be the result of a change in the orientation of the system or episodic mass loss.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Low-velocity encounters between our planet and any near-Earth object (NEO) in an Earth-like orbit may induce its temporary capture as a mini-moon. Such mini-moon episodes could lead the NEO to complete one or more revolutions around Earth when gravitationally bound, a temporarily-captured orbiter, like in the cases of 2006 RH<jats:sub>120</jats:sub> and 2020 CD<jats:sub>3</jats:sub>; sometimes not even one revolution is completed, a temporarily-captured flyby, like in the case of 1991 VG. Asteroid 2022 NX<jats:sub>1</jats:sub> experienced a temporarily-captured flyby in 1981, has had another one in 2022, and will become a temporarily-captured orbiter in 2051. This object occupies the edge of Earth’s co-orbital space and sometimes it approaches us following a horseshoe path.</jats:p>