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Three Z Camelopardalis-type dwarf novae exhibiting IW Andromedae-type phenomenon
Kato, Taichi
I found that V507 Cyg, IM Eri, and FY Vul are Z Cam-type dwarf novae and they showed sequences of standstill terminated by brightening, in contrast to fading as ordinary Z Cam stars do, followed by damping oscillation. These sequences are characteristic to IW And-type objects (also known as anomalous Z Cam stars). New additions to the IW And-type …
Merging Cluster Collaboration: Optical and Spectroscopic Survey of a Radio-selected Sample of 29 Merging Galaxy Clusters
Bradač, M.; Jee, M. J.; van Weeren, R. J. +11 more
Multi-band photometric and multi-object spectroscopic surveys of merging galaxy clusters allow for the characterization of the distributions of constituent DM and galaxy populations, constraints on the dynamics of the merging subclusters, and an understanding of galaxy evolution of member galaxies. We present deep photometric observations from Sub…
Searching for the GD-1 stream progenitor in Gaia DR2 with direct N-body simulations
Bovy, Jo; Webb, Jeremy J.
We perform a large suite of direct N-body simulations aimed at revealing the location of the progenitor, or its remnant, of the GD-1 stream. Data from Gaia DR2 reveal that the GD-1 stream extends over ≈100°, allowing us to determine the stream's leading and trailing ends. Our models suggest that the length of the stream is consistent with a dynami…
The Transiting Multi-planet System HD15337: Two Nearly Equal-mass Planets Straddling the Radius Gap
Torres, Guillermo; Cochran, William D.; Endl, Michael +53 more
We report the discovery of a super-Earth and a sub-Neptune transiting the star HD 15337 (TOI-402, TIC 120896927), a bright (V = 9) K1 dwarf observed by the Transiting Exoplanet Survey Satellite (TESS) in Sectors 3 and 4. We combine the TESS photometry with archival High Accuracy Radial velocity Planet Searcher spectra to confirm the planetary natu…
The magnetic early B-type Stars II: stellar atmospheric parameters in the era of Gaia
Wade, G. A.; Neiner, C.; Shultz, M. E. +6 more
Atmospheric parameters determined via spectral modelling are unavailable for many of the known magnetic early B-type stars. We utilized high-resolution spectra together with non-local thermodynamic equilibrium models to measure effective temperatures Teff and surface gravities log g of stars for which these measurements are not yet avai…
Detection of Rotational Acceleration of Bennu Using HST Light Curve Observations
Emery, J. P.; Chesley, S. R.; Noll, K. S. +7 more
We observed the near-Earth asteroid (101955) Bennu from the ground in 1999 and 2005, and with the Hubble Space Telescope (HST) in 2012, to constrain its rotation rate. The data reveal an acceleration of 2.64 ± 1.05 × 10-6 deg/day2, which could be due to a change in the moment of inertia of Bennu or to spin up from the Yarkovs…
Brown dwarf census with the Dark Energy Survey year 3 data and the thin disc scale height of early L types
Bechtol, K.; Smith, M.; Abbott, T. M. C. +46 more
In this paper we present a catalogue of 11 745 brown dwarfs with spectral types ranging from L0 to T9, photometrically classified using data from the Dark Energy Survey (DES) year 3 release matched to the Vista Hemisphere Survey (VHS) DR3 and Wide-field Infrared Survey Explorer (WISE) data, covering ≈2400 deg2 up to iAB = 22.…
The Martian Bow Shock Over Solar Cycle 23-24 as Observed by the Mars Express Mission
Holmström, M.; Wild, J. A.; Lester, M. +2 more
The Martian bow shock position is known to be correlated with solar extreme ultraviolet irradiance. Since this parameter is also correlated with the evolution of the solar cycle, it is expected that the Martian bow shock position should also vary over such a period. However, previous reports on this topic have often proved contradictory. Using 13 …
Clues on the Origin and Evolution of Massive Contact Binaries: Atmosphere Analysis of VFTS 352
Sana, Hugues; Tramper, Frank; Justham, Stephen +10 more
The massive O4.5 V + O5.5 V binary VFTS 352 in the Tarantula Nebula is one of the shortest-period and most massive overcontact binaries known. Recent theoretical studies indicate that some of these systems could ultimately lead to the formation of gravitational waves via black hole binary mergers through the chemically homogeneous evolution pathwa…
Strong lensing reveals jets in a sub-microJy radio-quiet quasar
Jackson, N.; Sluse, D.; Stacey, H. R. +2 more
We present e-MERLIN and European VLBI Network observations which reveal unambiguous jet activity within radio-quiet quasar HS 0810+2554. With an intrinsic flux density of 880 nJy, this is the faintest radio source ever imaged. The findings present new evidence against the idea that radio-loud and radio-quiet quasars are powered by different underl…