Search Publications
Zodiacal Exoplanets in Time (ZEIT). IX. A Flat Transmission Spectrum and a Highly Eccentric Orbit for the Young Neptune K2-25b as Revealed by Spitzer
Gaidos, Eric; Dalba, Paul A.; Rizzuto, Aaron C. +9 more
Transiting planets in nearby young clusters offer the opportunity to study the atmospheres and dynamics of planets during their formative years. To this end, we focused on K2-25b—a close-in (P = 3.48 days), Neptune-sized exoplanet orbiting a M4.5 dwarf in the 650 Myr Hyades cluster. We combined photometric observations of K2-25 covering a total of…
H- and Dissociation in Ultra-hot Jupiters: A Retrieval Case Study of WASP-18b
Madhusudhan, Nikku; Gandhi, Siddharth; Mandell, Avi
Atmospheres of a number of ultra-hot Jupiters (UHJs) with temperatures ≳2000 K have been observed recently. Many of these planets show largely featureless thermal spectra in the near-infrared observed with the HST WFC3 spectrograph (1.1-1.7 µm) even though this spectral range contains strong H2O opacity. Recent works have proposed…
Ultra-short-period Planets Are Stable against Tidal Inspiral
Schlaufman, Kevin C.; Hamer, Jacob H.
It has been unambiguously shown both in individual systems and at the population level that hot Jupiters experience tidal inspiral before the end of their host stars' main-sequence lifetimes. Ultra-short-period (USP) planets have orbital periods P < 1 day, rocky compositions, and are expected to experience tidal decay on similar timescales to h…
Physical Characterization of Interstellar Comet 2I/2019 Q4 (Borisov)
Tholen, David J.; Ye, Quan-Zhi; Hui, Man-To +2 more
We present a study of interstellar comet 2I/2019 Q4 (Borisov) using both preperihelion and postperihelion observations spanning late September 2019 through late January 2020. The intrinsic brightness of the comet was observed to continuously decline throughout the timespan, likely due to the decreasing effective scattering cross-section as a resul…
Simultaneous Optical Transmission Spectroscopy of a Terrestrial, Habitable-zone Exoplanet with Two Ground-based Multiobject Spectrographs
Charbonneau, David; Kempton, Eliza M. -R.; Diamond-Lowe, Hannah +2 more
Investigating the atmospheres of rocky exoplanets is key to performing comparative planetology between these worlds and the terrestrial planets that reside in the inner solar system. Terrestrial exoplanet atmospheres exhibit weak signals, and attempting to detect them pushes at the boundaries of what is possible for current instrumentation. We foc…
Observations of Binary Stars with the Differential Speckle Survey Instrument. IX. Observations of Known and Suspected Binaries, and a Partial Survey of Be Stars
Henry, Todd J.; van Belle, Gerard T.; Winters, Jennifer G. +13 more
We report 370 measures of 170 components of binary and multiple-star systems, obtained from speckle imaging observations made with the Differential Speckle Survey Instrument at Lowell Observatory's Discovery Channel Telescope in 2015 through 2017. Of the systems studied, 147 are binary stars, 10 are seen as triple systems, and 1 quadruple system i…
Spectroscopically Identified Cataclysmic Variables from the LAMOST Survey. I. The Sample
Qin, Li; Hou, Wen; Li, Yin-Bi +1 more
A sample of cataclysmic variables (CVs) is presented including spectroscopically identified 380 spectra of 245 objects, of which 58 CV candidates are new discoveries. The BaggingTopPush and the Random Forest algorithms are applied to the Fifth Data Release (DR5) of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) to retrieve …
Optical to Near-infrared Transmission Spectrum of the Warm Sub-Saturn HAT-P-12b
Deming, Drake; Nikolov, Nikolay; Sing, David K. +12 more
We present the transmission spectrum of HAT-P-12b through a joint analysis of data obtained from the Hubble Space Telescope Space Telescope Imaging Spectrograph and Wide Field Camera 3 and Spitzer, covering the wavelength range 0.3-5.0 µm. We detect a muted water vapor absorption feature at 1.4 µm attenuated by clouds, as well as a Ray…
WASP-117 b: An Eccentric Hot Saturn as a Future Complex Chemistry Laboratory
Changeat, Quentin; Venot, Olivia; Edwards, Billy +4 more
We present spectral analysis of the transiting Saturn-mass planet WASP-117 b, observed with the G141 grism of the Hubble Space Telescope's (HST) Wide Field Camera 3. We reduce and fit the extracted spectrum from the raw transmission data using the open-source software Iraclis before performing a fully Bayesian retrieval using the publicly availabl…
The Vanishing and Appearing Sources during a Century of Observations Project. I. USNO Objects Missing in Modern Sky Surveys and Follow-up Observations of a “Missing Star”
Gupta, Alok C.; Kochukhov, Oleg; Krisciunas, Kevin +19 more
In this paper we report the current status of a new research program. The primary goal of the “Vanishing and Appearing Sources during a Century of Observations” project is to search for vanishing and appearing sources using existing survey data to find examples of exceptional astrophysical transients. The implications of finding such objects exten…