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Physical properties of asteroid 308635 (2005 YU55) derived from multi-instrument infrared observations during a very close Earth approach
Altieri, B.; Metcalfe, L.; Pál, A. +19 more
The near-Earth asteroid 308635 (2005 YU55) is a potentially hazardous asteroid which was discovered in 2005 and passed Earth on Nov. 8, 2011 at 0.85 lunar distances. This was the closest known approach by an asteroid of several hundred metres in diameter since 1976 when an object of similar size passed at 0.5 lunar distances. We observe…
Evidence of rocky planetesimals orbiting two Hyades stars
Gänsicke, B. T.; Koester, D.; Farihi, J.
The Hyades is the nearest open cluster, relatively young and containing numerous A-type stars; its known age, distance, and metallicity make it an ideal site to study planetary systems around 2-3 M⊙ stars at an epoch similar to the late heavy bombardment. Hubble Space Telescope far-ultraviolet spectroscopy strongly suggests ongoing, ext…
A statistical study on O+ flux in the dayside magnetosheath
Nilsson, H.; Slapak, R.; Westerberg, L. G.
Studies on terrestrial oxygen ion (O+) escape into the interplanetary space have considered a number of different escape paths. Recent observations however suggest a yet insufficiently investigated additional escape route for hot O+: along open magnetic field lines in the high altitude cusp and mantle. Here we present a stati…
The Association of Polar Faculae with Polar Magnetic Patches Examined with Hinode Observations
Kubo, M.; Tsuneta, S.; Suematsu, Y. +2 more
The magnetic properties of the Sun's polar faculae are investigated with spectropolarimetric observations of the north polar region obtained by the Hinode satellite in 2007 September. Polar faculae are embedded in nearly all magnetic patches with fluxes greater than 1018 Mx, while magnetic patches without polar faculae dominate in the f…
Outflow versus Infall in Spiral Galaxies: Metal Absorption in the Halo of NGC 891
Miller, Eric D.; Bregman, Joel N.; Seitzer, Patrick +2 more
Gas accreting onto a galaxy will be of low metallicity while halo gas due to a galactic fountain will be of near-solar metallicity. We test these predictions by measuring the metal absorption line properties of halo gas 5 kpc above the plane of the edge-on galaxy NGC 891, using observations taken with HST/STIS toward a bright background quasar. Me…
Detection of the Compressed Primary Stellar Wind in η Carinae
Gull, T. R.; Corcoran, M. F.; Madura, T. I. +2 more
A series of three Hubble Space Telescope/Space Telescope Imaging Spectrograph spectroscopic mappings, spaced approximately one year apart, reveal three partial arcs in [Fe II] and [Ni II] emissions moving outward from η Carinae. We identify these arcs with the shell-like structures, seen in the three-dimensional hydrodynamical simulations, formed …
Accurate Characterization of High-degree Modes Using MDI Observations
Larson, T. P.; Schou, J.; Korzennik, S. G. +1 more
We present the first accurate characterization of high-degree modes, derived using the best Michelson Doppler Imager (MDI) full-disk full-resolution data set available. A 90 day long time series of full-disk 2 arcsec pixel-1 resolution Dopplergrams was acquired in 2001, thanks to the high rate telemetry provided by the Deep Space Networ…
A Peculiar Faint Satellite in the Remote Outer Halo of M31
Dotter, A.; Mackey, A. D.; Martin, N. F. +9 more
We present Hubble Space Telescope imaging of a newly discovered faint stellar system, PAndAS-48, in the outskirts of the M31 halo. Our photometry reveals this object to be comprised of an ancient and very metal-poor stellar population with age >~ 10 Gyr and [Fe/H] lsim -2.3. Our inferred distance modulus (m - M)0 = 24.57 ± 0.11 confi…
Forecasting propagation and evolution of CMEs in an operational setting: What has been learned
Mays, M. L.; Zheng, Yihua; Macneice, Peter +8 more
of the major types of solar eruption, coronal mass ejections (CMEs) not only impact space weather, but also can have significant societal consequences. CMEs cause intense geomagnetic storms and drive fast mode shocks that accelerate charged particles, potentially resulting in enhanced radiation levels both in ions and electrons. Human and technolo…
A Herschel-ATLAS study of dusty spheroids: probing the minor-merger process in the local Universe
Clements, D. L.; Smith, M.; Cooray, A. +25 more
We use multiwavelength (0.12-500 µm) photometry from Herschel-ATLAS, WISE, UKIDSS, SDSS and GALEX to study 23 nearby spheroidal galaxies with prominent dust lanes (DLSGs). DLSGs are considered to be remnants of recent minor mergers, making them ideal laboratories for studying both the interstellar medium (ISM) of spheroids and minor-merger-d…