Related papers: A Chondritic Solar Neighborhood
Recent discoveries of extrasolar planets at small orbital radii, or with significant eccentricities, indicate that interactions between massive planets and the disks of gas and dust from which they formed are vital for determining the final…
The compositions of stars are a critical diagnostic tool for many topics in astronomy such as the evolution of our Galaxy, the formation of planets, and the uniqueness of the Sun. Previous spectroscopic measurements indicate a large…
Planet formation is generally described in terms of a system containing the host star and a protoplanetary disc, of which the internal properties (e.g. mass and metallicity) determine the properties of the resulting planetary system.…
Circumstantial evidence suggests that most known extra-solar planetary systems are survivors of violent dynamical instabilities. Here we explore how giant planet instabilities affect the formation and survival of terrestrial planets. We…
The bulk composition of an exoplanet is commonly inferred from its average density. For small planets, however, the average density is not unique within the range of compositions. Variations of a number of important planetary…
The accretion of planetesimals onto white dwarf atmospheres allows determination of the composition of this polluting material. This composition is usually inferred from observed pollution levels by assuming it originated from a single…
Theoretical studies of giant planet formation suggest that substantial quantities of metals - elements heavier than hydrogen and helium - can be delivered by solid accretion during the envelope-assembly phase. This metal enhancement process…
We present a survey of >4,000 star compositions from the Hypatia Catalog to examine whether rocky exoplanets (i.e., those with rocky surfaces, dominated by silicates) might be geologically similar to Earth, at least with respect to…
White dwarfs are the burnt out cores of Sun-like stars and are the final fate of 97% of all stars in our Galaxy. The internal structure and composition of white dwarfs are hidden by their high gravities, which causes all elements, apart…
Simulations have shown that a diverse range of extrasolar terrestrial planet bulk compositions are likely to exist, based on the observed variations in host star elemental abundances. Based on recent studies, it is expected that a…
We present HST ultraviolet spectroscopy of the white dwarfs PG0843+516, PG1015+161, SDSS1228+1040, and GALEX1931+0117, which accrete circumstellar planetary debris formed from the destruction of asteroids. Combined with optical data, a…
Observations of circumstellar disks around stars as a function of stellar properties such as mass, metallicity, multiplicity, and age, provide constraints on theories concerning the formation and evolution of planetary systems. Utilizing…
This paper gives an overview of the properties of all possible equilibrium sequences of compact strange-matter stars with nuclear crusts, which range from strange stars to strange dwarfs. In contrast to their non-strange counterparts,…
Existing determinations show that n(C)/n(Fe) is more than a factor of 10 below solar in the atmospheres of three white dwarfs that appear to be externally-polluted. These results are not easily explained if the stars have accreted…
White dwarf stars frequently experience external pollution by heavy elements, and yet the intrinsically carbon-enriched DQ spectral class members fail to exhibit this phenomenon, representing a decades-old conundrum. This study reports a…
A significant fraction of white dwarfs (WDs) exhibit signs of ongoing accretion of refractory elements at rates $\sim10^3$--$10^7$ kg s$^{-1}$, among which, 37 WDs were detected to harbor dusty debris disks. Such a concurrence requires not…
Tidal disruption and subsequent accretion of planetesimals by white dwarfs can reveal the elemental abundances of rocky bodies in exoplanetary systems. Those abundances provide information on the composition of the nebula from which the…
The porosity of an asteroid is important when studying the evolution of our solar system through small bodies and for planning mitigation strategies to avoid disasters due to asteroid impacts. Our knowledge of asteroid porosity largely…
White dwarfs are routinely observed to have polluted atmospheres, and sometimes significant infrared excesses, that indicate ongoing accretion of circumstellar dust and rocky debris. Typically this debris is assumed to be in the form of a…
The present-day bulk elemental composition of an exoplanet can provide insight into a planet's formation and evolutionary history. Such information is now being measured for dozens of planets with state-of-the-art facilities using Bayesian…