Search Publications
Systematics and Consequences of Comet Nucleus Outgassing Torques
Jewitt, David
Anisotropic outgassing from comets exerts a torque sufficient to rapidly change the angular momentum of the nucleus, potentially leading to rotational instability. Here, we use empirical measures of spin changes in a sample of comets to characterize the torques, and to compare them with expectations from a simple model. Both the data and the model…
Rotation periods for cool stars in the open cluster NGC 3532. The transition from fast to slow rotation
Strassmeier, K. G.; Barnes, S. A.; James, D. J. +1 more
Context. A very rich cluster intermediate in age between the Pleiades (150 Myr) and the Hyades (600 Myr) is needed to probe the rotational evolution, especially the transition between fast and slow rotation that occurs between the two ages.
Aims: We study the rich 300 Myr-old open cluster NGC 3532 to probe this important transition and to pro…
ALMA Observations of the Sub-kpc Structure of the Host Galaxy of a z = 6.5 Lensed Quasar: A Rotationally Supported Hyper-Starburst System at the Epoch of Reionization
Fan, Xiaohui; Keeton, Charles R.; Walter, Fabian +11 more
We report Atacama Large Millimeter/Submillimeter Array (ALMA) observations of the dust continuum and [C II] emission of the host galaxy of J0439+1634, a gravitationally lensed quasar at z = 6.5. Gravitational lensing boosts the source-plane resolution to ~0"15 (~0.8 kpc). The lensing model derived from the ALMA data is consistent with the fiducial…
Data Mining Reconstruction of Magnetotail Reconnection and Implications for Its First-Principle Modeling
Sitnov, Mikhail; Stephens, Grant; Motoba, Tetsuo +1 more
Magnetic reconnection is a fundamental process providing topological changes of the magnetic field, reconfiguration of space plasmas and release of energy in key space weather phenomena, solar flares, coronal mass ejections and magnetospheric substorms. Its multiscale nature is difficult to study in observations because of their sparsity. Here we …
A Galactic survey of radio jets from massive protostars
Lumsden, S. L.; Purser, S. J. D.; Hoare, M. G. +1 more
In conjunction with a previous southern-hemisphere work, we present the largest radio survey of jets from massive protostars to date with high-resolution (~0.04 arcsec) Jansky Very Large Array observations towards two subsamples of massive star-forming regions of different evolutionary statuses: 48 infrared-bright, massive, young, stellar objects …
TESS Asteroseismology of α Mensae: Benchmark Ages for a G7 Dwarf and Its M Dwarf Companion
Butler, R. Paul; Chaplin, William J.; Stassun, Keivan G. +27 more
Asteroseismology of bright stars has become increasingly important as a method to determine the fundamental properties (in particular ages) of stars. The Kepler Space Telescope initiated a revolution by detecting oscillations in more than 500 main-sequence and subgiant stars. However, most Kepler stars are faint and therefore have limited constrai…
Dark Higgs dark matter
Slone, Oren; Pospelov, Maxim; Mondino, Cristina +1 more
A new U (1 ) "dark" gauge group coupled to the Standard Model (SM) via the kinetic mixing portal provides a dark matter candidate in the form of the Higgs field, hd, responsible for generating the mass of the dark photon, γd. We show that the condition mhd≤mγd , together with smalln…
The spiral structure in the Solar neighbourhood
Hou, L. G.
The spiral structure in the solar neighborhood is an important issue in astronomy. In the past few years, there has been significant progress in observation. The distances for a large number of good spiral tracers, i.e., giant molecular clouds, high-mass star-formation region masers, HII regions, O-type stars, and young open clusters, have been ac…
Inspecting the Cepheid Distance Ladder: the Hubble Space Telescope Distance to the SN Ia Host Galaxy NGC 5584
Mérand, Antoine; Breuval, Louise; Gieren, Wolfgang +7 more
The current tension between the direct and the early-universe measurements of the Hubble constant, H0, requires detailed scrutiny of all the data and methods used in the studies on both sides of the debate. The Cepheids in the Type Ia supernova (SN Ia) host galaxy NGC 5584 played a key role in the local measurement of H0. The…
37 new validated planets in overlapping K2 campaigns
Kuzuhara, M.; Tamura, M.; Fridlund, M. +24 more
We analysed 68 candidate planetary systems first identified during Campaigns 5 and 6 (C5 and C6) of the NASA K2 mission. We set out to validate these systems by using a suite of follow-up observations, including adaptive optics, speckle imaging, and reconnaissance spectroscopy. The overlap between C5 with C16 and C18, and C6 with C17, yields light…