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Combined geometrical modelling and white-light mass determination of coronal mass ejections
Vourlidas, Angelos; Bothmer, Volker; Pluta, Adam +2 more
Context. We use forward modelling on multi-viewpoint coronagraph observations to estimate the 3-dimensional morphology, initial speed and deprojected masses of Coronal Mass Ejections (CMEs). The CME structure is described via the Graduated Cylindrical Shell (GCS) model, which enables the measurement of CME parameters in a consistent and comparable…
High- and Low-α Disk Stars Separate Dynamically at All Ages
Ness, Melissa K.; Gandhi, Suroor S.
There is a dichotomy in the Milky Way in the [α/Fe]-[Fe/H] plane, in which stars fall into high-α and low-α sequences. The high-α sequence comprises mostly old stars, and the low-α sequence comprises primarily young stars. The origin of this dichotomy is uncertain. To better understand how the high- and low-α stars are affiliated, we examine if th…
Probing Structure in Cold Gas at z ≲ 1 with Gravitationally Lensed Quasar Sight Lines
Ellison, Sara L.; Kulkarni, Varsha P.; Lopez, Sebastian +3 more
Absorption spectroscopy of gravitationally lensed quasars (GLQs) enables study of spatial variations in the interstellar and/or circumgalactic medium of foreground galaxies. We report observations of four GLQs, each with two images separated by 0.″8-3.″0, that show strong absorbers at redshifts 0.4 < z abs < 1.3 in their spectra, …
The visual spectrum of Jupiter's Great Red Spot accurately modeled with aerosols produced by photolyzed ammonia reacting with acetylene
Baines, K. H.; Sromovsky, L. A.; Carlson, R. W. +2 more
We report results incorporating the optical properties of the red-tinted photochemically-generated aerosols of Carlson et al. (2016, Icarus 274, 106-115) in spectral models of Jupiter's Great Red Spot (GRS). This material - created in laboratory GRS simulations from acetylene reacting with photolytic products of ammonia produced by 0.2-µm ra…
From ridges in the velocity distribution to wiggles in the rotation curve
Martinez-Medina, Luis; Pichardo, Barbara; Peimbert, Antonio +1 more
Recently, the Gaiadata release 2 (DR2) showed us the richness in the kinematics of the Milky Way disc. Of particular interest is the presence of ridges covering the stellar velocity distribution, Vϕ-R; as shown by others, it is likely that these ridges are the signature of phase mixing, transient spirals, or the bar. Here, with a Galact…
HST/STIS analysis of the first main sequence pulsar CU Virginis
Pigulski, A.; Trigilio, C.; Leto, P. +9 more
Context. CU Vir has been the first main sequence star that showed regular radio pulses that persist for decades, resembling the radio lighthouse of pulsars and interpreted as auroral radio emission similar to that found in planets. The star belongs to a rare group of magnetic chemically peculiar stars with variable rotational period.
Aims: We…
Progenitor constraints on the Type Ia supernova SN 2014J from Hubble Space Telescope H β and [O III] observations
Graur, Or; Woods, Tyrone E.
Type Ia supernovae are understood to arise from the thermonuclear explosion of a carbon-oxygen white dwarf, yet the evolutionary mechanisms leading to such events remain unknown. Many proposed channels, including the classical single-degenerate scenario, invoke a hot, luminous evolutionary phase for the progenitor, in which it is a prodigious sour…
Observational Evidence for Summer Rainfall at Titan's North Pole
Sotin, Christophe; Barnes, Jason W.; Soderblom, Jason M. +13 more
Methane rain on Saturn's moon Titan makes it the only place, other than Earth, where rain interacts with the surface. When and where that rain wets the surface changes seasonally in ways that remain poorly understood. Here we report the discovery of a bright ephemeral feature covering an area of 120,000 km2 near Titan's north pole in ob…
NGTS-5b: a highly inflated planet offering insights into the sub-Jovian desert
Smalley, Barry; Jackman, James A. G.; Wheatley, Peter J. +32 more
Context. Planetary population analysis gives us insight into formation and evolution processes. For short-period planets, the sub-Jovian desert has been discussed in recent years with regard to the planet population in the mass/period and radius/period parameter space without taking stellar parameters into account. The Next Generation Transit Surv…
An efficient approach to extract parameters from star cluster CMDs: fitCMD
Bonatto, Charles
This work presents an approach (fitCMD) designed to obtain a comprehensive set of astrophysical parameters from colour-magnitude diagrams (CMDs) of star clusters. Based on initial mass function (IMF) properties taken from isochrones, fitCMD searches for the values of total (or cluster) stellar mass, age, global metallicity, foreground reddening, d…