The White Dwarfs Within 20 Parsecs of the Sun: Kinematics and Statistics

Sion, E. M.; Holberg, J. B.; Oswalt, Terry D.; McCook, G. P.; Wasatonic, R.

doi:10.1088/0004-6256/138/6/1681

Cited by 103 publications

(111 citation statements)

References 37 publications

(26 reference statements)

Supporting

Mentioning

102

Contrasting

Order By: Relevance

“…Of these, only two have T eff below 6600 K (at 6090 and 4660 K). Given that already about half a dozen cool DZ known within 20 pc of the Sun are brighter than this SDSS sample (including van Maanen 2 at only 4.3 pc, Sion et al 2009) this suggests that a large number of cooler DZ remain to be found.…”

Section: Introductionmentioning

confidence: 64%

Cool DZ white dwarfs in the SDSS

Koester

Girven²,

Gänsicke³

et al. 2011

A&A

View full text Add to dashboard Cite

Aims. We report the identification of 26 cool DZ white dwarfs that lie across and below the main sequence in the Sloan Digital Sky Survey (SDSS) (u − g) vs. (g − r) two-color diagram; 21 of these stars are new discoveries. Methods. The sample was identified by visual inspection of all spectra of objects that fall below the main sequence in the two-color diagram, as well as by an automated search for characteristic spectral features over a large area in color space that included the main sequence. The spectra and photometry provided by the SDSS project are interpreted with model atmospheres, including all relevant metals. Effective temperatures and element abundances are determined, while the surface gravity has to be assumed and was fixed at the canonical value of logg = 8. Results. These stars represent the extension of the well-known DZ sequence towards cooler temperatures and fill the gap around T eff = 6500 K present in a previous study. The metal abundances are similar to those in the hotter DZ, but the lowest abundances are missing, probably because of our selection procedures. The interpretation is complicated in terms of the accretion/diffusion scenario, because we do not know if accretion is still occurring or has ended long ago. Independent of that uncertainty, the masses of the metals currently present in the convection zones -and thus an absolute lower limit of the total accreted masses -of these stars are similar to the largest asteroids in our solar system.

show abstract

Section: Introductionmentioning

confidence: 64%

Cool DZ white dwarfs in the SDSS

Koester

Girven²,

Gänsicke³

et al. 2011

A&A

View full text Add to dashboard Cite

show abstract

“…14, 16, 17, 18, 22 and 25) must be ruled out as Hyades components, since their updated distances imply residual velocities of more than 20 km s −1 . Indeed, it is obvious that a cluster candidate can not have a residual velocity of the order of the velocity dispersion of field white dwarfs, which is ∼30 km s −1 in each spatial direction (Sion et al 2009). …”

Section: Membership Status Of New Hyades Candidatesmentioning

confidence: 99%

“…The objects are randomly distributed in the galactic X, Y, Z coordinates, with axes pointing to the Galactic centre (X), the direction of galactic rotation (Y), and the North Galactic Pole (Z). The U, V, W velocities are distributed according to a Gaussian weight function using the observed velocity distribution from Sion et al (2009) To derive the mean velocity and the velocity dispersion, Sion et al (2009) assumed zero radial velocity, which, at least, sets a lower limit to the velocity dispersion.…”

Section: Field White Dwarfs Contaminationmentioning

confidence: 99%

Spectroscopic and photometric studies of white dwarfs in the Hyades

Tremblay

Schilbach

Röser

et al. 2012

A&A

View full text Add to dashboard Cite

The Hyades cluster is known to harbour ten so-called classical white dwarf members. Numerous studies through the years have predicted that more than twice this amount of degenerate stars should be associated with the cluster. Using the PPMXL Catalog of proper motions and positions, a recent study proposed 17 new white dwarf candidates. We review the membership of these candidates by using published spectroscopic and photometric observations, as well as by simulating the contamination from field white dwarfs. In addition to the ten classical Hyades white dwarfs, we find six white dwarfs that may be of Hyades origin and three more objects that have an uncertain membership status due to their unknown or imprecise atmospheric parameters. Among those, two to three are expected as field stars contamination. Accurate radial velocity measurements will confirm or reject the candidates. One consequence is that the longstanding problem that no white dwarf older than ∼340 Myr appears to be associated with the cluster remains unsolved.

show abstract

“…Searches for such disks around the oldest white dwarfs have been unsuccessful (Kilic et al 2009), but about 15% of local white dwarfs contain metal-rich material in their photosphere, indicative of accretion from a residual dust reservoir (Sion et al 2009). Although these white dwarfs may have a variety of origins, they may include the progeny of the M 2-29-type disks.…”

Section: Evolution Of the Diskmentioning

confidence: 99%

Disk evaporation in a planetary nebula

Gęsicki

Zijlstra

Szyszka

et al. 2010

A&A

View full text Add to dashboard Cite

Aims. Binary interactions are believed to be important contributors to the structures seen in planetary nebulae (PN), and the sole cause of the newly discovered compact dust disks. The evolution of these disks is not clear, nor are the binary parameters required for their creation. Methods. Using HST imaging and VLT spectroscopy, both long-slit and integral field, we study the Galactic bulge planetary nebula M 2-29 for which a 3-year eclipse event of the central star has been attributed to a dust disk. Results. The central PN cavity of M 2-29 is being filled with a decreasingly, slow wind. An inner high density core is detected, of radius smaller than 250 AU, interpreted as a rotating gas/dust disk with a bipolar disk wind. The evaporating disk is argued to be the source of the slow wind. The central star is the source of a very fast wind (∼10 3 km s −1 ). An outer, partial ring is seen in the equatorial plane, expanding at 12 km s −1 . The azimuthal asymmetry is attributed to mass-loss modulation by an eccentric binary. A crucial point in disk evolution is represented by M 2-29 where ionization causes the gas to be lost, leaving a low-mass dust disk behind.

show abstract

The White Dwarfs Within 20 Parsecs of the Sun: Kinematics and Statistics

Cited by 103 publications

References 37 publications

Cool DZ white dwarfs in the SDSS

Cool DZ white dwarfs in the SDSS

Spectroscopic and photometric studies of white dwarfs in the Hyades

Disk evaporation in a planetary nebula

Contact Info

Product

Resources

About