Research Notes of the AAS
EISSN : 2515-5172
Published by: American Astronomical Society (10.3847)
Total articles ≅ 1,154
Latest articles in this journal
Research Notes of the AAS, Volume 6; https://doi.org/10.3847/2515-5172/ac7ab7
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.
Research Notes of the AAS, Volume 6; https://doi.org/10.3847/2515-5172/ac7aba
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.
Research Notes of the AAS, Volume 6; https://doi.org/10.3847/2515-5172/ac7ab9
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.
Research Notes of the AAS, Volume 6; https://doi.org/10.3847/2515-5172/ac79b8
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.
Research Notes of the AAS, Volume 6; https://doi.org/10.3847/2515-5172/ac79b9
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.
Research Notes of the AAS, Volume 6; https://doi.org/10.3847/2515-5172/ac7957
We analyzed archival data of the warm Neptune HD 106315c, an exoplanet with an extended atmosphere orbiting an F-type star with a 21 days period. We used data from the HARPS instrument covering three transits and employed the high-resolution transmission spectroscopy technique. Our analysis yielded a non-detection of sodium with an upper limit of 0.24% on the depth of the planetary feature. This can hint at the presence of Rayleigh scattering in the atmosphere and/or clouds in the upper atmosphere. The HD 106315 system with its two Neptune-sized planets remains an intriguing target for comparative planetology in the starting era of JWST and the upcoming Ariel mission.
Research Notes of the AAS, Volume 6; https://doi.org/10.3847/2515-5172/ac7809
The analysis of eighteen high resolution SWP spectra of the HgMn star HD 78316 (κ Cnc) recorded by the International Ultraviolet Explorer reveals that the far-ultraviolet flux of this star remained constant over the various observations with IUE. The TESS lightcurve of HD 78316 reveals a double-wave structure with a rotational period of about 6.25 days. The absence of far-ultraviolet variability and the reproducibility of the brightness in the V band during most IUE observations do not support the presence of large chemical gradients over the surface of κ Cnc at the time of the IUE observations.
Research Notes of the AAS, Volume 6; https://doi.org/10.3847/2515-5172/ac7808
Modern galaxy simulations have reached the complexity required to create sophisticated mock catalogs. Ananke is a set of nine mock catalogs constructed from synthetic surveys of three Milky Way-like galaxies from the Latte suite of FIRE simulations. Ananke provides observed quantities for comparison with modern large-scale stellar surveys. In SDSS-IV DR17, mock catalogs for the Apache Point Galactic Evolution Experiment (APOGEE) were built from Ananke synthetic surveys as a Value-Added Catalog, but were only provided as large flat files (∼>10's GB). Here we announce an >40 Tb SQL database for nine APOGEE-specific mock catalogs and describe additions to the data model necessary for effective user queries. The catalogs can be accessed on the free, science platform, SciServer—supported by the Institute for Data Intensive Engineering and Science at the Johns Hopkins University (IDIES); SciServer supports server-side analysis with commonly used coding languages and tools.
Research Notes of the AAS, Volume 6; https://doi.org/10.3847/2515-5172/ac780b
Galaxy morphological classification is a fundamental aspect of galaxy formation and evolution studies. Various machine learning tools have been developed for automated pipeline analysis of large-scale surveys, enabling a fast search for objects of interest. However, crowded regions in the image may pose a challenge as they can lead to bias in the learning algorithm. In this Research Note, we present galmask, an open-source package for unsupervised galaxy masking to isolate the central object of interest in the image. galmask is written in Python and can be installed from PyPI via the pip command.
Research Notes of the AAS, Volume 6; https://doi.org/10.3847/2515-5172/ac780a
We present WDJ220838.73+454434.04 (hereafter WD2208+454), a wide, co-moving white dwarf companion to the eclipsing binary system, AR Lacertae. The companion was discovered through the Backyard Worlds: Planet 9 citizen science collaboration. It has a separation of 21.″9 on the sky from the central eclipsing pair, translating to a projected separation of ∼930 au. We present a review of the physical properties and orbital parameters of this new addition to the system.