Search Publications
Evidence of nonthermal particles in coronal loops heated impulsively by nanoflares
Golub, L.; Tian, H.; De Pontieu, B. +21 more
The physical processes causing energy exchange between the Sun’s hot corona and its cool lower atmosphere remain poorly understood. The chromosphere and transition region (TR) form an interface region between the surface and the corona that is highly sensitive to the coronal heating mechanism. High-resolution observations with the Interface Region…
Magnetic moment and plasma environment of HD 209458b as determined from Lyα observations
Holmström, Mats; Lammer, Helmut; Kislyakova, Kristina G. +2 more
Transit observations of HD 209458b in the stellar Lyman-α(Lyα) line revealed strong absorption in both blue and red wings of the line interpreted as hydrogen atoms escaping from the planet’s exosphere at high velocities. The following sources for the absorption were suggested: acceleration by the stellar radiation pressure, natural spectral line b…
A VLBI resolution of the Pleiades distance controversy
Stauffer, John R.; Bower, Geoffrey C.; Melis, Carl +2 more
Because of its proximity and its youth, the Pleiades open cluster of stars has been extensively studied and serves as a cornerstone for our understanding of the physical properties of young stars. This role is called into question by the “Pleiades distance controversy,” wherein the cluster distance of 120.2 ± 1.5 parsecs (pc) as measured by the op…
On the origin of near-infrared extragalactic background light anisotropy
Gong, Yan; Cooray, Asantha; Matsuura, Shuji +13 more
Extragalactic background light (EBL) anisotropy traces variations in the total production of photons over cosmic history and may contain faint, extended components missed in galaxy point-source surveys. Infrared EBL fluctuations have been attributed to primordial galaxies and black holes at the epoch of reionization (EOR) or, alternately, intrahal…
Early 56Ni decay gamma rays from SN2014J suggest an unusual explosion
Diehl, Roland; Grebenev, Sergei A.; Greiner, Jochen +7 more
Type Ia supernovae result from binary systems that include a carbon-oxygen white dwarf, and these thermonuclear explosions typically produce 0.5 solar mass of radioactive 56Ni. The 56Ni is commonly believed to be buried deeply in the expanding supernova cloud. In SN2014J, we detected the lines at 158 and 812 kiloelectron volt…
On the prevalence of small-scale twist in the solar chromosphere and transition region
Golub, L.; Tian, H.; De Pontieu, B. +21 more
The solar chromosphere and transition region (TR) form an interface between the Sun’s surface and its hot outer atmosphere. There, most of the nonthermal energy that powers the solar atmosphere is transformed into heat, although the detailed mechanism remains elusive. High-resolution (0.33-arc second) observations with NASA’s Interface Region Imag…
Constraints on Mimas’ interior from Cassini ISS libration measurements
Charnoz, S.; Lainey, V.; Noyelles, B. +4 more
Like our Moon, the majority of the solar system’s satellites are locked in a 1:1 spin-orbit resonance; on average, these satellites show the same face toward the planet at a constant rotation rate equal to the satellite’s orbital rate. In addition to the uniform rotational motion, physical librations (oscillations about an equilibrium) also occur.…
The unresolved fine structure resolved: IRIS observations of the solar transition region
Golub, L.; Tian, H.; De Pontieu, B. +18 more
The heating of the outer solar atmospheric layers, i.e., the transition region and corona, to high temperatures is a long-standing problem in solar (and stellar) physics. Solutions have been hampered by an incomplete understanding of the magnetically controlled structure of these regions. The high spatial and temporal resolution observations with …
The Source Crater of Martian Shergottite Meteorites
Poulet, François; Werner, Stephanie C.; Ody, Anouck
Absolute ages for planetary surfaces are often inferred by crater densities and only indirectly constrained by the ages of meteorites. We show that the <5 million-year-old and 55-km-wide Mojave Crater on Mars is the ejection source for the meteorites classified as shergottites. Shergottites and this crater are linked by their coinciding meteori…
Super-Eddington Mechanical Power of an Accreting Black Hole in M83
Long, K. S.; Soria, R.; Kuntz, K. D. +5 more
Mass accretion onto black holes releases energy in the form of radiation and outflows. Although the radiative flux cannot substantially exceed the Eddington limit, at which the outgoing radiation pressure impedes the inflow of matter, it remains unclear whether the kinetic energy flux is bounded by this same limit. Here, we present the detection o…