Search Publications
The HST lightcurve of (486958) 2014 MU69
Stern, S. A.; Buie, M. W.; Spencer, J. R. +6 more
We report Hubble Space Telescope (HST) lightcurve observations of the New Horizons spacecraft encounter Kuiper Belt object (KBO) (486958) 2014 MU69 acquired near opposition in July 2017. In order to plan the optimum flyby sequence the New Horizons mission planners needed to learn as much as possible about the target in advance of the en…
Genus Statistic Applied to the X-Ray Remnant of SN 1572: Clues to the Clumpy Ejecta Structure of Type Ia Supernovae
Sato, Toshiki; Hughes, John P.; Williams, Brian J. +1 more
Clumpy structures are a common feature in X-ray images of young Type Ia supernova remnants (SNRs). Although the precise origin of such clumps remains unclear, there are three generic possibilities: clumpiness imposed during the explosion, hydrodynamic instabilities that act during the remnant’s evolution, and preexisting structures in the ambient …
Exoplanet transits with next-generation radio telescopes
Pope, Benjamin J. S.; Withers, Paul; Vogt, Marissa F. +1 more
Nearly everything we know about extrasolar planets to date comes from optical astronomy. While exoplanetary aurorae are predicted to be bright at low radio frequencies (<1 GHz), we consider the effect of an exoplanet transit on radio emission from the host star. As radio emission from solar-like stars is concentrated in active regions, a planet…
A Comparison of the X-Ray Properties of FU Ori-type Stars to Generic Young Stellar Objects
Hillenbrand, Lynne A.; Kuhn, Michael A.
Like other young stellar objects (YSOs), FU Ori-type stars have been detected as strong X-ray emitters. However, little is known about how the outbursts of these stars affect their X-ray properties. We assemble available X-ray data from XMM-Newton and Chandra observations of 16 FU Ori stars, including a new XMM-Newton observation of Gaia 17bpi dur…
Solar microflares: a case study on temperatures and the Fe XVIII emission
Del Zanna, G.; Mitra-Kraev, U.
In this paper, we discuss the temperature distribution and evolution of a microflare, simultaneously observed by Hinode's X-Ray Telescope (XRT), its Extreme Ultraviolet Imaging Spectrometer (EIS), as well as the Atmospheric Imaging Assembly (AIA) on-board the Solar Dynamics Observatory (SDO). Using EIS lines, we find that during peak emission the …
Constraints on the Galactic Inner Halo Assembly History from the Age Gradient of Blue Horizontal-branch Stars
Whitten, Devin D.; Beers, Timothy C.; Placco, Vinicius M. +6 more
We present an analysis of the relative age distribution of the Milky Way halo, based on samples of blue horizontal-branch (BHB) stars obtained from the Panoramic Survey Telescope and Rapid Response System and Galaxy Evolution Explorer photometry, as well a Sloan Digital Sky Survey spectroscopic sample. A machine-learning approach to the selection …
Kepler Object of Interest Network. III. Kepler-82f: a new non-transiting 21 M⊕ planet from photodynamical modelling
Mallonn, M.; Becker, A. C.; Ribas, I. +13 more
Context. The Kepler Object of Interest Network (KOINet) is a multi-site network of telescopes around the globe organised for follow-up observations of transiting planet candidate Kepler objects of interest with large transit timing variations (TTVs). The main goal of KOINet is the completion of their TTV curves as the Kepler telescope stopped obse…
TOI-150: A Transiting Hot Jupiter in the TESS Southern CVZ
Butler, R. Paul; Schneider, Donald P.; Kollmeier, Juna A. +24 more
We report the detection of a hot Jupiter ({M}p={1.75}-0.17+0.14 {M}{{J}}, R p = 1.38 ± 0.04 R J) orbiting a middle-aged star ({log}g={4.152}-0.043+0.030) in the Transiting Exoplanet Survey Satellite (TESS) southern continuous viewing zone (β = -79.°59). We co…
Constraining the thermal properties of planetary surfaces using machine learning: Application to airless bodies
Furfaro, Roberto; Cambioni, Saverio; Delbo, Marco +2 more
We present a new method for the determination of the surface properties of airless bodies from measurements of the emitted infrared flux. Our approach uses machine learning techniques to train, validate, and test a neural network representation of the thermophysical behavior of the atmosphereless body given shape model, illumination and observatio…
Ongoing astrometric microlensing events from VVV and Gaia
Evans, N. W.; Belokurov, V.; Lucas, P. W. +2 more
We extend predictive microlensing event searches using the Vista Variables in the Via Lactea survey and the second Gaia data release. We identify two events with maxima in 2019 that require urgent follow-up. First, we predict that the nearby M2 dwarf L 338-152 will align with a background source with a closest approach of 35^{+35}_{-23} mas on 201…