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Variability of Disk Emission in Pre-main Sequence and Related Stars. V. Occultation Events from the Innermost Disk Region of the Herbig Ae Star HD 163296
Bayyari, Ammar; Sitko, Michael L.; Grady, Carol A. +8 more
HD 163296 is a Herbig Ae star that underwent a dramatic ~0.8 magnitude drop in brightness in the V photometric band in 2001 and a brightening in the near-IR in 2002. Because the star possesses Herbig-Haro objects traveling in outflowing bipolar jets, it was suggested that the drop in brightness was due to a clump of dust entrained in a disk wind, …
A Deep Search for Five Molecules in the 49 Ceti Debris Disk
Hughes, A. Meredith; Roberge, Aki; Moór, Attila +9 more
Surprisingly strong CO emission has been observed from more than a dozen debris disks around nearby main-sequence stars. The origin of this CO is unclear, in particular whether it is left over from the protoplanetary disk phase or is second-generation material released from collisions between icy bodies like debris dust. The primary unexplored ave…
The IGRINS YSO Survey II: Veiling Spectra of Pre-main-sequence Stars in Taurus-Auriga
Tofflemire, Benjamin M.; López-Valdivia, Ricardo; Mace, Gregory +5 more
We present measurements of the H- and K-band veiling for 141 young stellar objects (YSOs) in the Taurus-Auriga star-forming region using high-resolution spectra from the Immersion Grating Near-Infrared Spectrometer. In addition to providing measurements of rH and rK, we produce low-resolution spectra of the excess emission ac…
[C II] and CO Emission along the Bar and Counter-arms of NGC 7479
Laine, Seppo; Fadda, Dario; Appleton, Philip N.
We present new SOFIA [C II] and ALMA COJ=1→0 observations of the nearby asymmetric barred spiral galaxy NGC 7479. The data, which cover the whole bar of the galaxy and the counter-arms visible in the radio continuum, are analyzed in conjunction with a wealth of existing visible, infrared, radio, and X-ray data. As in most normal galaxie…
Core Mass Estimates in Strong Lensing Galaxy Clusters: A Comparison between Masses Obtained from Detailed Lens Models, Single-halo Lens Models, and Einstein Radii
Sharon, K.; Gladders, M. D.; Bleem, L. E. +7 more
The core mass of galaxy clusters is both an important anchor of the radial mass distribution profile and a probe of structure formation. With thousands of strong lensing galaxy clusters being discovered by current and upcoming surveys, timely, efficient, and accurate core mass estimates are needed. We assess the results of two efficient methods to…
Searching for Extragalactic Exoplanetary Systems: The Curious Case of BD+20 2457
Limberg, Guilherme; Rossi, Silvia; Borbolato, Lais +4 more
Planets and their host stars carry a long-term memory of their origin in their chemical compositions. Thus, identifying planets formed in different environments improves our understating of planetary formation. Although restricted to detecting exoplanets within the solar vicinity, we might be able to detect planetary systems that formed in small e…
Fe XVII 2p-3s Line Ratio Diagnostic of Shock Formation Radius in O Stars
Leutenegger, Maurice A.; Grell, Gabriel J.; Shah, Chintan
The 2p-3s lines of Fe XVII in the X-ray spectrum of the O-type star ζ Puppis exhibit an anomalous (3G + M2)/(3F) line ratio of ~1.4, in comparison with ~2.4 for almost all other collisionally excited astrophysical spectra. Based on the work of Mauche et al., we conjectured that the strong UV field of ζ Puppis produces the observed ratio by depopul…
Thermal Pressures in the Interstellar Medium away from Stellar Environments
Tripp, Todd M.; Jenkins, Edward B.
Interstellar thermal pressures can be measured using C I absorption lines that probe the pressure-sensitive populations of the fine-structure levels of its ground state. In a survey of C I absorption toward Galactic hot stars, Jenkins & Tripp found evidence of small amounts (~0.05%) of gas at high pressures ( $p/k\gg {10}^{4}\,{\mat…
Discovery of Two Infrared Objects with Strong Ice Absorption in the Akari Slitless Spectroscopic Survey of the Galactic Plane
Onaka, Takashi; Sakon, Itsuki; Shimonishi, Takashi +1 more
We discover two infrared objects that show deep absorption features of H2O, CO2, and CO ices in the AKARI/Infrared Camera slitless spectroscopic survey of the Galactic plane in 2.5-13 µm. Both objects are neither located in known star-forming regions nor in known dense clouds. For one of the objects, Object 1, we succes…
Multiwavelength Observations of the RV Tauri Variable System U Monocerotis: Long-term Variability Phenomena That Can Be Explained by Binary Interactions with a Circumbinary Disk
Stassun, Keivan G.; Kastner, Joel H.; Sabin, Laurence +7 more
We present an X-ray through submillimeter observations of the classical RV Tauri (RVb-type) variable U Mon, a post-asymptotic giant branch (AGB) binary with a circumbinary disk (CBD). Our SMA observations indicate a CBD diameter of ≲550 au. Our XMM-Newton observations make U Mon the first RV Tauri variable detected in X-rays. The X-ray emission is…