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Pulsations of the low-mass ZZ Ceti star HS 1824+6000

Steinfadt, Justin D. R. and Bildsten, Lars and Ofek, Eran O. and Kulkarni, Shri R. (2008) Pulsations of the low-mass ZZ Ceti star HS 1824+6000. Publications of the Astronomical Society of the Pacific, 120 (872). pp. 1103-1111. ISSN 0004-6280.

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Measuring g-mode pulsations of isolated white dwarfs can reveal their interior properties to high precision. With a spectroscopic mass of ≈0.51 M⊙ (log g = 7.82), the DAV white dwarf HS 1824+6000 is near the transition between carbon/oxygen-core and helium-core white dwarfs, motivating our photometric search for additional pulsations from the Palomar 60-inch telescope. We confirmed (with much greater precision) the three frequencies: 2.751190 ± 0.000010 mHz (363.479 sec), 3.116709 ± 0.000006 mHz (320.851 sec), 3.495113 ± 0.000009 mHz (286.114 sec), previously found by B. Voss and collaborators, and found an additional pulsation at 4.443120 ± 0.000012 mHz (225.067 sec). These observed frequencies are similar to those found in other ZZ Ceti white dwarfs of comparable mass (e.g. log g < 8). We hope that future observations of much lower-mass ZZ Ceti stars (< 0.4 M⊙) will reveal pulsational differences attributable to a hydrogen covered helium core.

Item Type:Article
Related URLs:
URLURL TypeDescription
Ofek, Eran O.0000-0002-6786-8774
Kulkarni, Shri R.0000-0001-5390-8563
Additional Information:© 2008 The Astronomical Society of the Pacific. Received 2008 July 22; accepted 2008 August 27; published 2008 October 7. We thank Anjum Mukadam for alerting us to the existence of this object and the referee for comments that clarified our presentation. We thank Phil Arras for useful discussion on pulsations in He-core WDs. This work was supported by the National Science Foundation under grants PHY 05-51164 and AST 07-07633.
Funding AgencyGrant Number
NSFPHY 05-51164
NSFAST 07-07633
Subject Keywords:dwarf cooling sequence; whole Earth telescope; helium white-dwarfs; instability strip; empirical determination; stellar evolution; oxygen cores; time-series; discovery; NGC-6791
Issue or Number:872
Record Number:CaltechAUTHORS:STEpasp08
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13623
Deposited By: Tony Diaz
Deposited On:27 May 2009 21:39
Last Modified:03 Oct 2019 00:41

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