Skip to content
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Menu
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Menu
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Publication Details
AFRICAN RESEARCH NEXUS
SHINING A SPOTLIGHT ON AFRICAN RESEARCH
earth and planetary sciences
Periodic variations in the O-C diagrams of five pulsation frequencies of the DB white dwarf EC 20058-5234
Astrophysical Journal, Volume 765, No. 1, Article 5, Year 2013
Notification
URL copied to clipboard!
Description
Variations in the pulsation arrival time of five independent pulsation frequencies of the DB white dwarf EC 20058-5234 individually imitate the effects of reflex motion induced by a planet or companion but are inconsistent when considered in unison. The pulsation frequencies vary periodically in a 12.9 year cycle and undergo secular changes that are inconsistent with simple neutrino plus photon-cooling models. The magnitude of the periodic and secular variations increases with the period of the pulsations, possibly hinting that the corresponding physical mechanism is located near the surface of the star. The phase of the periodic variations appears coupled to the sign of the secular variations. The standards for pulsation-timing-based detection of planetary companions around pulsating white dwarfs, and possibly other variables such as subdwarf B stars, should be re-evaluated. The physical mechanism responsible for this surprising result may involve a redistribution of angular momentum or a magnetic cycle. Additionally, variations in a supposed combination frequency are shown to match the sum of the variations of the parent frequencies to remarkable precision, an expected but unprecedented confirmation of theoretical predictions. © 2013. The American Astronomical Society. All rights reserved..
Authors & Co-Authors
Dalessio, James
United States, Newark
University of Delaware
United States
Delaware Asteroseismology Research Center
Sullivan, Denis J.
New Zealand, Wellington
Victoria University of Wellington
Provençal, Judith L.
United States, Newark
University of Delaware
United States
Delaware Asteroseismology Research Center
Shipman, Harry L.
United States, Newark
University of Delaware
United States
Delaware Asteroseismology Research Center
Sullivan, Tiri
New Zealand, Wellington
Victoria University of Wellington
Kilkenny, David
South Africa, Bellville
University of the Western Cape
Fraga, Luciano
Chile, La Serena
Southern Observatory for Astrophysical Research
Sefako, Ramotholo R.
South Africa, Cape Town
South African Astronomical Observatory
Statistics
Citations: 25
Authors: 8
Affiliations: 6
Identifiers
Doi:
10.1088/0004-637X/765/1/5
ISSN:
0004637X
e-ISSN:
15384357