The white dwarf Giclas 29-38 has attracted much attention due to its large infrared excess and the suggestion that excess might be due to a companion brown dwarf. We observed this object using speckle interferometry at the Keck telescope, obtaining diffraction-limited resolution (55 milliarcseconds) at K band, and found it unresolved. Assuming the entire K band excess is due to a single point-l...

A recent analysis of Chandra X-ray data the metal-polluted white dwarf (WD) G29-38 has revealed emission that can be attributed to accretion debris from a planetary body. In light this detection we revisit here archival XMM-Newton observations which only an upper limit was derived in past due presence relatively bright nearby source. An these multiple energy bands allows disentangling at locati...

We compare capital requirements derived by tail conditional expectation (TCE) with those derived by tail conditional median (TCM) and find that there is no clear-cut relationship between these two measures in empirical data. Our results highlight the relevance of TCM as a robust alternative to TCE, especially for regulatory control. JEL Classification: G10, G11, G23, G29

Designed to compete with fiat currencies, bitcoin proposes it is a crypto-currency alternative. Bitcoin makes a number of false claims, including: bitcoin can be a reserve currency for banking; hoarding equals saving; and that we should believe bitcoin can expand by deflation to become a global transactional currency supply. Bitcoin’s developers combine technical implementation proficiency with...

We report the detection of the heavy elements Ca, Mg, Fe in the atmosphere of the variable DA white dwarf G29-38. The abundance of Ca can be understood only if accretion from interstellar matter is going on currently at a high rate. This lends support also to the interpretation of the observed infrared excess as due to heated circumstellar material, from which the accretion onto the star takes ...

Metals in the photospheres of white dwarfs with TeA between 12,000 and 25,000 K should gravitationally settle out of these atmospheres in 1Y2 weeks. Temporal variations in the line strengths of these metals could provide a direct measurement of episodic metal accretion. Using archival VLTand Keck spectroscopy, we find evidence that the DAZd white dwarf G29-38 shows significant changes in its Ca...