Results 11 to 20 of about 676 (225)
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
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Identification of DQ Serpentis and DT Serpentis as symbiotic stars [PDF]
Astronomy and Astrophysics Supplement Series, 1997 Optical and near infrared spectroscopy of the stars DQ Ser and DT Ser are presented. DQ Ser shows a late-type continuum (M3 - M5) with emission lines of Balmer series, HeI, HeII, [OIII], OI and CaII triplet while DT Ser presents a earlier spectral type with emission of Balmer lines, HeI, HeII and [OIII].
D. Cieslinski +3 more
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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.
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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
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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
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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
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Gravitational Redshift Detection from the Magnetic White Dwarf Harbored in RX J1712.6–2414
The Astrophysical Journal, 2023 Gravitational redshift is a fundamental parameter that allows us to determine the mass-to-radius ratio of compact stellar objects, such as black holes, neutron stars, and white dwarfs (WDs).
Takayuki Hayashi +4 more
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Captured at millimeter wavelengths: a flare from the classical T Tauri star DQ Tauri [PDF]
Astronomy & Astrophysics, 2008 For several hours on 2008 April 19 the T Tauri spectroscopic binary DQ Tau was observed to brighten, reaching a maximum detected flux of 468 mJy and likely making it (briefly) the brightest object at 3 mm in the Taurus star-forming region. We present the light curve of a rarely before observed millimeter flare originating in the region around a pre ...
Salter, D. M. +2 more
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The OmegaWhite Survey for short-period variable stars – IV. Discovery of the warm DQ white dwarf OW J175358.85−310728.9 [PDF]
Monthly Notices of the Royal Astronomical Society, 2017 11 pages, 8 figures, 7 tables.
Macfarlane, S. A. +12 more
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Polarization observations of DQ Her stars and other cataclysmic variables [PDF]
Monthly Notices of the Royal Astronomical Society, 1986 © Royal Astronomical Society. Linear and circular polarizations are presented for the DQ Her stars FO Aqr, AE Aqr, EX Hya, AO Psc and V1223 Sgr and for 17 other cataclysmic variables. Upper limits (~0.1 per cent in circular) are set to any periodic varia- tions in the polarization for the DQ Her stars.
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