Search Publications
Discovery of a Metal-poor, Luminous Post-AGB Star that Failed the Third Dredge-up.
Wood, P. R.; Asplund, M.; Van Winckel, H. +3 more
Post-asymptotic giant branch (post-AGB) stars are known to be chemically diverse. In this paper we present the first observational evidence of a star that has failed the third dredge-up (TDU). J005252.87-722842.9 is an A-type (T eff = 8250 ± 250 K) luminous (8200 ± 700 L ⊙) metal-poor ([Fe/H] = -1.18 ± 0.10) low-mass (M …
GRAVITY Spectro-interferometric Study of the Massive Multiple Stellar System HD 93206 A
Henning, Th.; van Boekel, R.; Brandner, W. +9 more
Characterization of the dynamics of massive star systems and the astrophysical properties of the interacting components are a prerequisite for understanding their formation and evolution. Optical interferometry at milliarcsecond resolution is a key observing technique for resolving high-mass multiple compact systems. Here, we report on Very Large …
2004 TT357: A Potential Contact Binary in the Trans-Neptunian Belt
Noll, Keith S.; Thirouin, Audrey; Sheppard, Scott S.
We report photometric observations of the trans-Neptunian object 2004 TT357 obtained in 2015 and 2017 using the 4.3 m Lowell’s Discovery Channel Telescope. We derive a rotational period of 7.79 ± 0.01 hr and a peak-to-peak lightcurve amplitude of 0.76 ± 0.03 mag. 2004 TT357 displays a large variability that can be explained b…
Novel Analysis of the Multiwavelength Structure of the Relativistic Jet in Quasar 3C 273
Jamrozy, Marek; Stawarz, Łukasz; Harris, D. E. +4 more
We present a detailed analysis of the best-quality multiwavelength data gathered for the large-scale jet in the core-dominated quasar 3C 273. We analyze all the archival observations of the target with the Chandra X-ray Observatory, the far-ultraviolet observations with the Hubble Space Telescope, and the 8.4 GHz map obtained with the Very Large A…
High-resolution Spectroscopic Abundances of Red Giant Branch Stars in NGC 6681
McWilliam, Andrew; Chaboyer, Brian; O'Malley, Erin M. +1 more
We obtain high-resolution spectra of nine red giant branch stars in NGC 6681 and perform the first detailed abundance analysis of stars in this cluster. We confirm cluster membership for these stars based on consistent radial velocities of 214.5 ± 3.7 km s-1 and find a mean [Fe/H] = -1.63 ± 0.07 dex and [α/Fe] = 0.42 ± 0.11 dex. Additio…
Further Constraints on Variations in the Initial Mass Function from Low-mass X-ray Binary Populations
Kundu, Arunav; Coulter, David A.; Zepf, Stephen E. +6 more
We present constraints on variations in the initial mass function (IMF) of nine local early-type galaxies based on their low-mass X-ray binary (LMXB) populations. Comprised of accreting black holes and neutron stars, these LMXBs can be used to constrain the important high-mass end of the IMF. We consider LMXB populations beyond the cores of the ga…
A Submillimeter Perspective on the Goods Fields. II. The High Radio Power Population in the Goods-N
Wang, W. -H.; Owen, F. N.; Barger, A. J. +2 more
We use ultradeep 20 cm data from the Karl G. Jansky Very Large Array and 850 µm data from SCUBA-2 and the Submillimeter Array of an 124 arcmin2 region of the Chandra Deep Field-north to analyze the high radio power ({P}20{cm}> {10}31 erg s-1 Hz-1) population. We find that 20 (42 ± 9%)…
Is There a CME Rate Floor? CME and Magnetic Flux Values for the Last Four Solar Cycle Minima
St. Cyr, O. C.; Webb, D. F.; Howard, R. A. +1 more
The recent prolonged activity minimum has led to the question of whether there is a base level of the solar magnetic field evolution that yields a “floor” in activity levels and also in the solar wind magnetic field strength. Recently, a flux transport model coupled with magneto-frictional simulations has been used to simulate the continuous magne…
Action-based Dynamical Modeling for the Milky Way Disk: The Influence of Spiral Arms
Bovy, Jo; Rix, Hans-Walter; Trick, Wilma H. +1 more
RoadMapping is a dynamical modeling machinery developed to constrain the Milky Way’s (MW) gravitational potential by simultaneously fitting an axisymmetric parametrized potential and an action-based orbit distribution function (DF) to discrete 6D phase-space measurements of stars in the Galactic disk. In this work, we demonstrate RoadMapping's rob…
ALMA CO Clouds and Young Star Complexes in the Interacting Galaxies IC 2163 and NGC 2207
Brinks, Elias; Struck, Curtis; Elmegreen, Bruce G. +5 more
Atacama Large Millimeter Array (ALMA) observations of CO(1-0) emission in the interacting galaxies IC 2163 and NGC 2207 are used to determine the properties of molecular clouds and their association with star-forming regions observed with the Hubble Space Telescope. Half of the CO mass is in 249 clouds, each more massive than 4.0× {10}5…