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Photometric variability in a warm, strongly magnetic DQ white dwarf, SDSS J103655.39+652252.2
dc.contributor.author | Williams, Kurtis | pt_BR |
dc.contributor.author | Winget, Donald Earl | pt_BR |
dc.contributor.author | Montgomery, Michael Houston | pt_BR |
dc.contributor.author | Dufour, Patrick | pt_BR |
dc.contributor.author | Kepler, Souza Oliveira | pt_BR |
dc.contributor.author | Hermes, James J. | pt_BR |
dc.contributor.author | Falcon, Ross E. | pt_BR |
dc.contributor.author | Winget, K. I. | pt_BR |
dc.contributor.author | Bolte, Michael | pt_BR |
dc.contributor.author | Rubin, Kate H. R. | pt_BR |
dc.contributor.author | Liebert, James | pt_BR |
dc.date.accessioned | 2015-01-20T02:15:27Z | pt_BR |
dc.date.issued | 2013 | pt_BR |
dc.identifier.issn | 0004-637X | pt_BR |
dc.identifier.uri | http://hdl.handle.net/10183/109077 | pt_BR |
dc.description.abstract | We present the discovery of photometric variability in the DQ white dwarf SDSS J103655.39+652252.2 (SDSS J1036+6522). Time-series photometry reveals a coherent monoperiodic modulation at a period of 1115.64751(67) s with an amplitude 0.442% ± 0.024%; no other periodic modulations are observed with amplitudes >~0.13%. The period, amplitude, and phase of this modulation are constant within errors over 16 months. The spectrum of SDSS J1036+6522 shows magnetic splitting of carbon lines, and we use Paschen–Back formalism to develop a grid of model atmospheres for mixed carbon and helium atmospheres. Our models, while reliant on several simplistic assumptions, nevertheless match the major spectral and photometric properties of the star with a self-consistent set of parameters: Teff ≈ 15,500 K, log g ≈ 9, log(C/He) = −1.0, and a mean magnetic field strength of 3.0 ± 0.2 MG. The temperature and abundances strongly suggest that SDSS J1036+6522 is a transition object between the hot, carbon-dominated DQs and the cool, heliumdominated DQs. The variability of SDSS J1036+6522 has characteristics similar to those of the variable hot carbon-atmosphere white dwarfs (DQVs), however, its temperature is significantly cooler. The pulse profile of SDSS J1036+6522 is nearly sinusoidal, in contrast with the significantly asymmetric pulse shapes of the known magnetic DQVs. If the variability in SDSS J1036+6522 is due to the same mechanism as other DQVs, then the pulse shape is not a definitive diagnostic on the absence of a strong magnetic field in DQVs. It remains unclear whether the root cause of the variability in SDSS J1036+6522 and the other hot DQVs is the same. | en |
dc.format.mimetype | application/pdf | |
dc.language.iso | eng | pt_BR |
dc.relation.ispartof | The astrophysical journal. Bristol. Vol. 769, no. 2 (June 2013), 123, 11 p. | pt_BR |
dc.rights | Open Access | en |
dc.subject | Stars: evolution | en |
dc.subject | Estrelas magneticas | pt_BR |
dc.subject | Anãs brancas | pt_BR |
dc.subject | Stars: individual (SDSS J103655.39+652252.2) | en |
dc.subject | Stars: magnetic field | en |
dc.subject | Magnetismo estelar | pt_BR |
dc.subject | Fotometria estelar | pt_BR |
dc.subject | Stars: oscillations (including pulsations) | en |
dc.subject | White dwarfs | en |
dc.title | Photometric variability in a warm, strongly magnetic DQ white dwarf, SDSS J103655.39+652252.2 | pt_BR |
dc.type | Artigo de periódico | pt_BR |
dc.identifier.nrb | 000900653 | pt_BR |
dc.type.origin | Estrangeiro | pt_BR |
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