Results 11 to 20 of about 24,589 (267)
Rapid Evolution of the White Dwarf Pulsar AR Scorpii
The Astrophysical Journal Letters, 2023 Analysis of AR Sco optical light curves spanning 9 yr shows a secular change in the relative amplitudes of the beat pulse pairs generated by the two magnetic poles of its rotating white dwarf.
Peter Garnavich +6 more
doaj +1 more source
Missing metals in DQ stars: A simple explanation
Astronomy & Astrophysics, 2022 Classical DQ stars are white dwarfs whose atmospheres contain detectable traces of carbon brought up to the surface by a convective dredge-up process. Intriguingly, unlike other white dwarf spectral classes, DQ stars virtually never show signs of external pollution by elements heavier than carbon.
openaire +2 more sources
A Hot DQ White Dwarf in the Open Star Cluster M35 [PDF]
The Astrophysical Journal, 2006 We report the discovery of a hot DQ white dwarf, NGC 2168:LAWDS 28, that is a likely member of the 150-Myr old cluster NGC 2168 (Messier 35). The spectrum of the white dwarf is dominated by CII features. The effective temperature is difficult to estimate but likely > 20,000 K based on the temperatures of hot DQs with similar spectra.
Williams, Kurtis A. +3 more
openaire +2 more sources
The Astrophysical Journal, 2023 DQ Tau is a unique young high-eccentricity binary system that exhibits regular magnetic reconnection flares and pulsed accretion near periastron. We conducted NuSTAR, Swift, and Chandra observations during the 2022 July 30 periastron to characterize X ...
Konstantin V. Getman +5 more
doaj +1 more source
Model atmosphere analysis of the extreme DQ white dwarf GSC2U J131147.2+292348 [PDF]
, 2003 A new model atmosphere analysis for the peculiar DQ white dwarf discovered by Carollo et al. (2002) is presented. The effective temperature and carbon abundance have been estimated by fitting both the photometric data (UBJ,VRF,IN,JHK) and a low ...
A. Spagna +16 more
core +2 more sources
On the formation of hot DQ white dwarfs [PDF]
, 2009 We present the first full evolutionary calculations aimed at exploring the origin of hot DQ white dwarfs. These calculations consistently cover the whole evolution from the born-again stage to the white dwarf cooling track.
A. D. Romero +13 more
core +4 more sources
The Astrophysical Journal, 2022 Abstract We continue our comprehensive theoretical investigation of the spectral evolution of white dwarfs based on sophisticated simulations of element transport. In this paper, we focus on the transformation of PG 1159 stars into DO/DB white dwarfs due to the gravitational settling of heavy elements and then into DQ white dwarfs ...
A. Bédard, P. Bergeron, P. Brassard
openaire +2 more sources
An Initial Survey of White Dwarfs in the Sloan Digital Sky Survey [PDF]
, 2003 An initial assessment is made of white dwarf and hot subdwarf stars observed in the Sloan Digital Sky Survey. In a small area of sky (190 square degrees), observed much like the full survey will be, 269 white dwarfs and 56 hot subdwarfs are identified ...
Alan Uomoto +47 more
core +1 more source
Recurring millimeter flares as evidence for star-star magnetic reconnection events in the DQ Tauri PMS binary system [PDF]
Astronomy and Astrophysics, 2010 Observations of the T Tauri spectroscopic binary DQ Tau in April 2008 captured an unusual flare at 3 mm, which peaked at an observed max flux of 0.5 Jy (about 27x the quiescent value). Here we present follow-up mm observations that demonstrate a periodicity to the phenomenon.
Salter, D. M. +7 more
openaire +3 more sources
The 1.17-day orbit of the double-degenerate (DA+DQ) NLTT 16249 [PDF]
, 2012 New spectroscopic observations show that the double degenerate system NLTT 16249 is in a close orbit (a = 5.6+/-0.3 R_sun) with a period of 1.17 d. The total mass of the system is estimated between 1.47 and 2.04 M_sun but it is not expected to merge ...
Dreizler +9 more
core +3 more sources