91福利

The Isaac Newton Telescope (INT) Photometric H-halpha Survey of the Northern Galactic plane (IPHAS, Drew et al. 2005) is a powerful tool for selecting effectively emission line stars. More than 50% of the IPHAS emitters are suggested to be classical Be stars (Corradi et al., 2008). We proposed this class of stars, which are intrinsically bright and relatively young (< 100 Myr old), as novel structure tracers of the Milky Way disc. The focus of the talk is on a sub-sample of 67 classical Be stars that are drawn out of our larger sample of 248 newly uncovered classical Be stars, in a section of the Galactic disc towards the Perseus Arm. I will present the optical spectroscopic follow-up and the spectral classification of the
sample. I will discuss the determination of interstellar reddenings and the problems concerning it, along with the assessment of spectroscopic parallaxes.

The discussion will focus on the study of the spatial distribution of the sample. The stars are confirmed to be distant classical Be stars, found at heliocentric distances ranging between ~2 kpc and ~12 kpc. However, the errors on the distances are too large to allow statistical distinction between models
placing the stars in the spiral arms or in a smooth exponential declining distribution. The total sample of 248 objects doubles the number of known classical Be stars in this part of the Galactic plane and it is offered for more exploitation in future, when Gaia parallaxes will be available.

Twenty years after the discovery of the first exoplanets, our knowledge of which stellar properties influence
planet formation is still far away to be complete. Furthermore, most of our current knowledge on planet formation is based on observations of main-sequence stars.

In this contribution I will give an overview of my research work, showing the results of a high-resolution,
optical spectra study of a sample of nearby late-type stars. The observations and analysis (kinematics, age, stellar parameters determination ...) will be described. I will focus on the metallicity distribution of stars with and without known debris discs and/or planetary companions, setting the results in the context of planet formation models. Then, I will present the first results on the analysis of the metallicity and elemental abundances of a large
sample of evolved stars with and without known planetary companions.

The precise form of the equation of state (EOS) for neutron stars (NS) has long been an outstanding problem within astrophysics. There have been numerous theoretically derived EOS proposed over the previous few decades, each of which define a NS mass-radius relation and predict a maximum NS mass. In order to eliminate some of the contending theories we must however turn to observations.

Within this talk I will describe our ongoing work within the area of High Mass X-ray Binaries (HMXB) in which we have attempted to determine the upper mass limit for neutron stars. The systems in which this can be achieved are rare, and the main part of this talk will comprise our work on 3 HMXB systems containing an eclipsing X-ray pulsar : OAO 1657-415, EXO 1722-363 and IGR J18027-2016.

The companion massive star in each of these systems is extremely obscured and is only observable in the near-infrared (NIR). Observations obtained over the last few years from ESO VLT and the NIR spectrograph ISSAC has allowed the construction of an orbital solution and a corresponding NS mass range determination for each system, the first time this has been achieved in the NIR.

My three-part presentation will cover: (1) highlights from my main sequence-based research, including modelling observations from Doppler radial velocity, transit timing variation, and direct imaging exoplanet searches, (2) highlights from my post-main sequence-based research, including characterizing planetary evolution in single-star and binary systems, and sourcing white dwarf pollution through dynamical instabilities, and (3) my potential contributions to the ERC group, including investigations of outstanding unsolved issues in stellar and planetary astrophysics through white dwarf studies.

Semiconductor and Metal-Oxide Nanocrystal Simulations with Linear-Scaling PAW DFT

We have undertaken a study to identify nearby cataclysmic variables (CVs) and related objects in the solar neighborhood through a proper motion based approach. We start with the new SUPERBLINK proper motion survey, which is sensitive down to 40 mas/yr and select candidates from this using Near-UV magnitudes from GALEX, K magnitudes from 2Mass, and V magnitudes derived from Digital Sky Survey plates. We present results from numerous observing runs at the MDM Observatory with both the 1.3m McGraw-Hill Telescope and the 2.4m Hiltner including a new cataclysmic variable and a sample of 169 newly discovered white dwarf main sequence binaries.