Search Publications
The MUSCLES Treasury Survey. I. Motivation and Overview
Loyd, R. O. Parke; Kowalski, Adam F.; Hawley, Suzanne L. +19 more
Ground- and space-based planet searches employing radial velocity techniques and transit photometry have detected thousands of planet-hosting stars in the Milky Way. With so many planets discovered, the next step toward identifying potentially habitable planets is atmospheric characterization. While the Sun-Earth system provides a good framework f…
Photolytic Hazes in the Atmosphere of 51 Eri b
Morley, C. V.; Zahnle, K.; Moses, J. I. +1 more
We use a 1D model to address photochemistry and possible haze formation in the irradiated warm Jupiter, 51 Eridani b. The intended focus was to be carbon, but sulfur photochemistry turns out to be important. The case for organic photochemical hazes is intriguing but falls short of being compelling. If organic hazes form, they are likeliest to do s…
Space Telescope and Optical Reverberation Mapping Project. IV. Anomalous Behavior of the Broad Ultraviolet Emission Lines in NGC 5548
Im, M.; Geier, S.; Brandt, W. N. +98 more
During an intensive Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS) UV monitoring campaign of the Seyfert 1 galaxy NGC 5548 performed from 2014 February to July, the normally highly correlated far UV continuum and broad emission line variations decorrelated for ∼60-70 days, starting ∼75 days after the first HST/COS observation. Foll…
Living with a Red Dwarf: Rotation and X-Ray and Ultraviolet Properties of the Halo Population Kapteyn's Star
Guinan, Edward F.; Engle, Scott G.; Durbin, Allyn
As part of Villanova's Living with a Red Dwarf program, we have obtained UV, X-ray, and optical data of the Population II red dwarf -- Kapteyn's Star. Kapteyn's Star is noteworthy for its large proper motions and high radial velocity of ∼+245 km s-1. As the nearest Pop II red dwarf, it serves as an old age anchor for calibrating activit…
On the Composition of Young, Directly Imaged Giant Planets
Fortney, J. J.; Zahnle, K.; Moses, J. I. +6 more
The past decade has seen significant progress on the direct detection and characterization of young, self-luminous giant planets at wide orbital separations from their host stars. Some of these planets show evidence for disequilibrium processes like transport-induced quenching in their atmospheres; photochemistry may also be important, despite the…
The Hot Companion and Circumbinary Disk of the Be Star HR 2142
Gies, Douglas R.; Wang, Luqian; Peters, Geraldine J. +1 more
We present a spectroscopic investigation of the Be+sdO binary system HR 2142 that is based upon large sets of ultraviolet observations from the International Ultraviolet Explorer (IUE) and ground-based Hα observations. We measured radial velocities for the Be star component from these spectra and computed a revised orbit. In order to search for th…
Light-curve Analysis of Neon Novae
Kato, Mariko; Hachisu, Izumi
We analyzed light curves of five neon novae, QU Vul, V351 Pup, V382 Vel, V693 CrA, and V1974 Cyg, and determined their white dwarf (WD) masses and distance moduli on the basis of theoretical light curves composed of free-free and photospheric emission. For QU Vul, we obtained a distance of d ∼ 2.4 kpc, reddening of E(B - V) ∼ 0.55, and WD mass of …
The Nucleus of the Planetary Nebula EGB 6 as a Post-Mira Binary
Bond, Howard E.; Munari, Ulisse; Ciardullo, Robin +3 more
EGB 6 is a faint, large, ancient planetary nebula (PN). Its central star, a hot DAOZ white dwarf (WD), is a prototype of a rare class of PN nuclei associated with dense, compact emission-line knots. The central star also shows excess fluxes in both the near-infrared (NIR) and mid-infrared (MIR). In a 2013 paper, we used Hubble Space Telescope (HST…
Dust and Polycyclic Aromatic Hydrocarbon in the Pre-transitional Disk around HD 169142
Seok, Ji Yeon; Li, Aigen
The pre-transitional disk around the Herbig Ae star HD 169142 shows a complex structure of possible ongoing planet formation in dust thermal emission from the near-infrared (IR) to millimeter wavelength range. Also, a distinct set of broad emission features at 3.3, 6.2, 7.7, 8.6, 11.3, and 12.7 µ {{m}}, commonly attributed to polycyclic arom…
Investigating the Circumstellar Disk of the Be Shell Star 48 Librae
Okazaki, A. T.; Carciofi, A. C.; Bednarski, D. +6 more
A global disk oscillation implemented in the viscous decretion disk (VDD) model has been used to reproduce most of the observed properties of the well known Be star ζ Tau. 48 Librae shares several similarities with ζ Tau—they are both early-type Be stars, display shell characteristics in their spectra, and exhibit cyclic V/R variations—but has som…