Search Publications
The Relation between the Mass Accretion Rate and the Disk Mass in Class I Protostars
Kóspál, Ágnes; Fiorellino, Eleonora; Cruz-Sáenz de Miera, Fernando +5 more
Evidence of a relation between the mass accretion rate and the disk mass is established for young, Class II pre-main-sequence stars. This observational result opened an avenue to test theoretical models and constrain the initial conditions of disk formation, fundamental in the understanding of the emergence of planetary systems. However, it is bec…
K2 Photometry on Oscillation Mode Variability: The New Pulsating Hot B Subdwarf Star EPIC 220422705
Ma, Xiao-Yu; Zong, Weikai; Fu, Jian-Ning +4 more
We present an analysis of oscillation mode variability in the hot B subdwarf star EPIC 220422705, a new pulsator discovered from ~78 days of K2 photometry. The high-quality light curves provide a detection of 66 significant independent frequencies, from which we identified nine incomplete potential triplets and three quintuplets. Those g- and p-mu…
Simultaneous Observations of Chromospheric Evaporation and Condensation during a C-class Flare
Li, Dong; Hong, Zhenxiang; Ning, Zongjun
We explored simultaneous observations of chromospheric evaporation and condensation during the impulsive phase of a C6.7 flare on 2019 May 9. The solar flare was simultaneously observed by multiple instruments, i.e., the New Vacuum Solar Telescope (NVST), the Interface Region Imaging Spectrograph, the Atmospheric Imaging Assembly (AIA), Fermi, the…
Gaia EDR3 bright star parallax zero-point using stellar clusters
Flynn, C.; Sekhri, R.; Venville, T. +4 more
We examine the zero-point of parallaxes in the Gaia EDR3 (Early Data Release 3, Gaia Collaboration (2021a)), using stars in open and globular clusters. Our aim is to check for zero-point systematics between bright stars G < 12 (which includes some important distance scale calibrators) and faint stars G > 14, for which the parallax scale has …
Radial and Local Time Variations in the Thickness of Jupiter's Magnetospheric Current Sheet
Hospodarsky, G. B.; Khurana, K. K.; Paranicas, C. P. +1 more
The magnetic field observations from the Galileo, Ulysses, Voyager 1 and 2, and Pioneer 10 and 11 spacecraft are analyzed to understand the structures and thickness of the Jovian magnetospheric current sheet. Using a new technique that can determine the motion of the spacecraft relative to the current sheet, we have built the first global map of t…
X-Ray Reverberation Mapping of Ark 564 Using Gaussian Process Regression
Ingram, Adam; Reynolds, Christopher S.; García, Javier A. +15 more
Ark 564 is an extreme high-Eddington narrow-line Seyfert 1 galaxy, known for being one of the brightest, most rapidly variable soft X-ray active galactic nuclei (AGN), and for having one of the lowest temperature coronae. Here, we present a 410 ks NuSTAR observation and two 115 ks XMM-Newton observations of this unique source, which reveal a very …
Blanco DECam Bulge Survey (BDBS). V. Cleaning the foreground populations from Galactic bulge colour-magnitude diagrams using Gaia EDR3
Rich, R. Michael; Kunder, Andrea; Johnson, Christian I. +8 more
Aims: The Blanco DECam Bulge Survey (BDBS) has imaged more than 200 square degrees of the southern Galactic bulge, providing photometry in the ugrizy filters for ∼250 million unique stars. The presence of a strong foreground disk population, along with complex reddening and extreme image crowding, has made it difficult to constrain the presen…
A selection function toolbox for subsets of astronomical catalogues
Everall, Andrew; Boubert, Douglas
Large catalogues are ubiquitous throughout astronomy, but most scientific analyses are carried out on smaller samples selected from these catalogues by chosen cuts on catalogued quantities. The selection function of that scientific sample - the probability that a star in the catalogue will satisfy these cuts and so make it into the sample - is thu…
Unresolved Binaries in the Intermediate Mass Range in the Pleiades Star Cluster
Carraro, Giovanni; Seleznev, Anton F.; Malofeeva, Alina A.
The identification of binary stars of different mass ratios in resolved stellar populations is a challenging task. We show how the photometric diagram constructed with the pseudocolors (H-W2)-W1 versus W2-(BP-K) can be employed to estimate the binary and multiple star ratios and the distribution of their component mass ratio q effectively. As an a…
Galactic Chemical Evolution of Exoplanet Hosting Stars: Are High-mass Planetary Systems Young?
Manoj, P.; Narang, Mayank; Swastik, C. +5 more
The imprints of stellar nucleosynthesis and chemical evolution of the galaxy can be seen in different stellar populations, with older generation stars showing higher α-element abundances and the later generations becoming enriched with iron-peak elements. The evolutionary connections and chemical characteristics of circumstellar disks, stars, and …