Search Publications
Understanding the Angular Momentum Evolution of T Tauri and Herbig Ae/Be Stars
Osorio, Yeisson; Hernández, Jesús; Roman-Lopes, Alexandre +8 more
We investigate a sample of six Herbig Ae/Be stars belonging to the Orion OB1 association, as well as 73 low-mass objects, members of the σ Orionis cluster, in order to explore the angular momentum evolution at early stages of evolution, and its possible connection with main-sequence Ap/Bp magnetic stars. Using FIES and HECTOCHELLE spectra, we obta…
Occultation of a Large Star by the Large Plutino (28978) Ixion on 2020 October 13 UTC
Bosh, Amanda S.; Person, Michael J.; Levine, Stephen E. +3 more
We observed the occultation of the star Gaia DR2 4056440205544338944 by (28978) Ixion. The event was observed from two Lowell Observatory sites, using the 4.3 m Lowell Discovery Telescope (LDT), near Happy Jack, AZ, USA, and a 0.32 m telescope co-mounted with the Titan Monitoring telescope on Lowell's Mars Hill campus in Flagstaff, AZ. The LDT cho…
Radial Segregation between Red Giant Populations in the Globular Cluster NGC 3201: Tentative Role of Varying Mass among the Progenitors
Kravtsov, Valery; Calderón, Francisco A.
In the globular cluster NGC 3201, we study subpopulations (SPs) of red giants (RGs) distinguished by their characteristics. In its central part, we make use of multicolor Hubble Space Telescope (HST) photometry coupled with spectroscopy of RGs spread out over a larger cluster face. In the color index CI $=\,({m}_{{\rm{F}}275{\rm{W}}}-{m}_{{\rm{F}}…
The Galactic Chemical Evolution of Chlorine
Pilachowski, C. A.; Maas, Z. G.
We measured 35Cl abundances in 52 M giants with metallicities in the range -0.5 < [Fe/H] < 0.12. Abundances and atmospheric parameters were derived using infrared spectra from CSHELL on the NASA Infrared Telescope Facility and from optical echelle spectra. We measured Cl abundances by fitting a H35Cl molecular feature a…
Measuring Young Stars in Space and Time. II. The Pre-main-sequence Stellar Content of N44
Gennaro, Mario; Dolphin, Andrew E.; Klessen, Ralf S. +9 more
The Hubble Space Telescope survey Measuring Young Stars in Space and Time (MYSST) entails some of the deepest photometric observations of extragalactic star formation, capturing even the lowest-mass stars of the active star-forming complex N44 in the Large Magellanic Cloud. We employ the new MYSST stellar catalog to identify and characterize the c…
Phase Modeling of the TRAPPIST-1 Planetary Atmospheres
Kane, Stephen R.; Fauchez, Thomas; Selsis, Franck +2 more
Transiting compact multiplanet systems provide many unique opportunities to characterize the planets, including studies of size distributions, mean densities, orbital dynamics, and atmospheric compositions. The relatively short orbital periods in these systems ensure that events requiring specific orbital locations of the planets (such as primary …
Anomalous Stellar Populations in Low-surface-brightness Galaxies
Schombert, James; McGaugh, Stacy
We present new Hubble Space Telescope WFC3 near-IR observations of the color-magnitude diagrams (CMDs) in two low-surface-brightness galaxies, F575-3 and F615-1, notable for having no current star formation based on a lack of Hα emission. Key features of the near-IR CMDs are resolved, such as the red giant branch (RGB), the asymptotic giant branch…
Seeking Echoes of Circumstellar Disks in Kepler Light Curves
Kenyon, Scott J.; Bromley, Benjamin C.; Leonard, Austin +3 more
Light echoes of flares on active stars offer the opportunity for direct detection of circumstellar dust. We revisit the problem of identifying faint echoes in postflare light curves, focusing on debris disks from ongoing planet formation. Starting with simulations, we develop an algorithm for estimating the radial extent and total mass from disk e…
Herschel Photometric Observations of LITTLE THINGS Dwarf Galaxies
Madden, Suzanne C.; Gomez, Haley L.; Brinks, Elias +6 more
We present here far-infrared photometry of galaxies in a sample that is relatively unexplored at these wavelengths: low-metallicity dwarf galaxies with moderate star formation rates. Four dwarf irregular galaxies from the LITTLE THINGS survey are considered, with deep Herschel PACS and SPIRE observations at 100, 160, 250, 350, and 500 µm. Re…
New Subgrouping of Multiple Stellar Populations in NGC 2808 Based on Low-resolution Spectroscopy
Kim, Jaeyeon; Han, Sang-Il; Chung, Chul +3 more
We performed low-resolution spectroscopy for the red giant branch stars in an intriguing globular cluster (GC) NGC 2808, which hosts subpopulations with extreme helium and light-element abundances. In order to trace N, C, and Ca abundance differences among subpopulations, we measured CN, CH, and Ca II H&K spectral indices, respectively. We ide…