Search Publications
Efficiently Imaging Accreting Protoplanets from Space: Reference Star Differential Imaging of the PDS 70 Planetary System Using the HST/WFC3 Archival PSF Library
Zhou, Yifan; Bowler, Brendan P.; Sanghi, Aniket
Accreting protoplanets provide key insights into how planets assemble from their natal protoplanetary disks. Recently, Zhou et al. (2021) used angular differential imaging (ADI) with Hubble Space Telescope's Wide Field Camera 3 (HST/WFC3) to recover the young accreting planet PDS 70 b in F656N (Hα) at a signal-to-noise ratio (S/N) of 7.9. In this …
Determining the Timescale over Which Stellar Feedback Drives Turbulence in the Interstellar Medium: A Study of Four Nearby Dwarf Irregular Galaxies
McQuinn, Kristen B. W.; Dolphin, Andrew E.; van Zee, Liese +2 more
Stellar feedback is fundamental to the modeling of galaxy evolution, as it drives turbulence and outflows in galaxies. Understanding the timescales involved are critical for constraining the impact of stellar feedback on the interstellar medium. We analyzed the resolved star formation histories along with the spatial distribution and kinematics of…
Influence of the Gaia-Sausage-Enceladus on the Density Shape of the Galactic Stellar Halo Revealed by Halo K Giants from the LAMOST Survey
Zhao, Gang; Yang, Chengqun; Pei, Wenxiang +2 more
We present a study of the influence of the Gaia-Sausage-Enceladus (GSE) on the density shape of the Galactic stellar halo using 11,624 K giants from the LAMOST survey. Every star is assigned a probability of being a member of the GSE based on its spherical velocities and metallicity by a Gaussian mixture model. We divide the stellar halo into two …
Apparent Motion of the Circumstellar Envelope of CQ Tau in Scattered Light
Strakhov, Ivan A.; Goliguzova, Maria V.; Safonov, Boris S. +1 more
The study of spiral structures in protoplanetary disks is of great importance for understanding the processes in the disks, including planet formation. Bright spiral arms were detected in the disk of young star CQ Tau by Uyama et al. in the H and L bands. The spiral arms are located inside the gap in millimeter-sized dust, discovered earlier using…
SCExAO and Keck Direct Imaging Discovery of a Low-mass Companion Around the Accelerating F5 Star HIP 5319
Currie, Thayne; Tamura, Motohide; Bailey, John I., III +26 more
We present the direct imaging discovery of a low-mass companion to the nearby accelerating F star, HIP 5319, using SCExAO coupled with the CHARIS, VAMPIRES, and MEC instruments in addition to Keck/NIRC2 imaging. CHARIS JHK (1.1-2.4 µm) spectroscopic data combined with VAMPIRES 750 nm, MEC Y, and NIRC2 L p photometry is best matche…
Evolution of the Hub-filament Structures in IC 5146 in the Context of the Energy Balance of Gravity, Turbulence, and Magnetic Field
Kwon, Woojin; Soam, Archana; Cho, Jungyeon +3 more
We present the results of 850 µm polarization and C18O (3 - 2) line observations toward the western hub-filament structure (W-HFS) of the dark Streamer in IC 5146 using the James Clerk Maxwell Telescope SCUBA-2/POL-2 and HARP instruments. We aim to investigate how the relative importance of the magnetic field, gravity, and turbule…
Tracers of Dense Gas in the Outer Galaxy
Jose, Jessy; Kim, Kee-Tae; Kauffmann, Jens +5 more
We have mapped $\mathrm{HCN}$ and HCO+ (J = 1 → 0) line emission toward a sample of seven star-forming regions (with $12+\mathrm{log}[{\rm{O}}/{\rm{H}}]$ ranging from 8.34 to 8.69) in the outer Milky Way (Galactocentric distance >9.5 kpc), using the 14 m radio telescope of the Taeduk Radio Astronomy Observatory. We compare these two …
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 …
The COS CGM Compendium. IV. Effects of Varying Ionization Backgrounds on Metallicity Determinations in the z < 1 Circumgalactic Medium
Fox, Andrew J.; Lehner, Nicolas; Howk, J. Christopher +3 more
Metallicity estimates of circumgalactic gas based on absorption-line measurements typically require photoionization modeling to account for unseen ionization states. We explore the impact of uncertainties in the extreme-ultraviolet background (EUVB) radiation on such metallicity determinations for the z < 1 circumgalactic medium. In particular,…