相关论文: Perfecting our set of spectrophotometric standard …

We use star counts from 13 deep HST fields imaged with the {\it Wide Field Camera - 2} in order to constrain the amount of dark matter in the Galaxy that can be in the form of low-mass main sequence stars or white-dwarfs. Based on the…

We identified 46 unresolved source candidates in the Hubble Ultra Deep Field, down to i775 = 29.5. Unresolved objects were identified using a parameter S, which measures the deviation from the curve-of-growth of a point source. Extensive…

A sample of white dwarfs is selected from SDSS DR3 imaging data using their reduced proper motions, based on improved proper motions from SDSS plus USNO-B combined data. Numerous SDSS and followup spectra (Kilic et al. 2005) are used to…

We present follow-up spectroscopy of 711 white dwarfs within 100 pc, and present a detailed model atmosphere analysis of the 100 pc white dwarf sample in the SDSS footprint. Our spectroscopic follow-up is complete for 83% of the white…

We present a spectroscopic analysis of white dwarfs found in the Kiso survey. Spectroscopic observations at high signal-to-noise ratio have been obtained for all DA and DB stars in the Kiso Schmidt ultraviolet excess survey (KUV stars).…

We have serendipitously discovered a previously-unknown, bright source (B_T = 11.75+/-0.07 mag) with a very blue V_T-K_s color, to which we have named Albus 1. A photometric and astrometric study using Virtual Observatory tools has shown…

We present the calibration of the [$\alpha/$Fe] element in terms of ultra-violet excess for 465 dwarf stars with spectral type F0-K2. We used a single calibration, fitted to a third degree polynomial with a square of the correlation…

Based on the astrometry and photometry in Gaia DR3, we identified new nearby white dwarfs and validated those that had been missed from recent white dwarf catalogues despite being previously documented. To ensure the reliability of their…

We present an overview of the sample of northern hemisphere white dwarfs within 40 pc of the Sun detected from $Gaia$ Data Release 2 (DR2). We find that 521 sources are spectroscopically confirmed degenerate stars, 111 of which were first…

AIMS: With our low-resolution spectroscopic observing program for selected blue proper motion stars, we tried to find new white dwarfs (WDs) in the solar neighbourhood. METHODS: We used the LSPM catalogue with a lower proper motion limit of…

We present medium resolution spectroscopy and multi-epoch VRI photometry for 21 new nearby (< 50 pc) white dwarf systems brighter than V ~ 17. Of the new systems, ten are DA (including a wide double degenerate system with two DA…

We present ugriz photometry and optical spectroscopy for 28 DB and DO white dwarfs with temperatures between 28,000K and 45,000K. About 10 of these are particularly well-observed; the remainder are candidates. These are the hottest DB stars…

A total of 81 DA white dwarfs have been observed with the Cosmic Origins Spectrograph on the Hubble Space Telescope in a snapshot program. The targets were selected to be in the $T_{\rm eff}$ range from 17000 - 25000 K, where optical metal…

We present an analysis of long-term photometric variability for nearby red dwarfs at optical wavelengths. The sample consists of 264 M dwarfs south of DEC = +30 with V-K = 3.96-9.16 and Mv~10-20 (spectral types M2V-M8V), most of which are…

We present the results of a medium resolution optical spectroscopic survey of 92 cool ($3,000 \lesssim T_{\rm eff} \lesssim 4,500\,$K) southern TESS candidate planet hosts, and describe our spectral fitting methodology used to recover…

Using light curves from the HATNet survey for transiting extrasolar planets we investigate the optical broad-band photometric variability of a sample of 27,560 field K and M dwarfs selected by color and proper-motion. A total of 2120 stars…

We present a method which uses colour-colour cuts on SDSS photometry to select white dwarfs with hydrogen rich (DA) atmospheres without the recourse to spectroscopy. This method results in a sample of DA white dwarfs that is 95% complete at…

We present Spitzer 5-15 micron spectroscopy of one cool white dwarf and 3.6-8 micron photometry of 51 cool white dwarfs with T_eff < 6000 K. The majority of our targets have accurate BVRIJHK photometry and trigonometric parallax…

As they evolve, white dwarfs undergo major changes in surface composition, a phenomenon known as spectral evolution. In particular, some stars enter the cooling sequence with helium atmospheres (type DO) but eventually develop hydrogen…

We present spectra of 59 nearby stars candidates, M dwarfs and white dwarfs, previously identified using high proper motion catalogues and the DENIS database. We review the existing spectral classification schemes and spectroscopic parallax…