Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Full Refereed Journal Article (PDF/Postscript)
· Full Refereed Scanned Article (GIF)
· References in the article
· Citations to the Article (49) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (4)
· Reads History
·
· Translate This Page
Title:
Periodic and secular variations in the lightcurve of dwarf nova EX Hydrae
Authors:
Vogt, N.; Krzeminski, W.; Sterken, C.
Affiliation:
AA(European Southern Observatory, Santiago, Chile), AB(Polska Akademia Nauk, Centrum Astronomiczne, Warsaw, Poland), AC(Brussel, Vrije Universiteit, Brussels, Belgium)
Publication:
Astronomy and Astrophysics, vol. 85, no. 1-2, May 1980, p. 106-112. Research supported by the Fonds de la Recherche Fondamentale Collective. (A&A Homepage)
Publication Date:
05/1980
Category:
Astrophysics
Origin:
STI
NASA/STI Keywords:
ASTRONOMICAL PHOTOMETRY, DWARF STARS, LIGHT CURVE, NOVAE, X RAY SOURCES, BINARY STARS, ELECTROPHOTOMETRY, MASS TRANSFER, PERIODIC VARIATIONS
Comment:
A&AA ID. AAA027.122.088
Bibliographic Code:
1980A&A....85..106V

Abstract

Extensive photoelectric observations of EX Hya were obtained between 1962 and 1976 at different telescopes and observatories. Evaluation of the data reveals a decrease of the orbital period at the rate of 5.2 x 10 to the -12th. This period change is likely caused by mass transfer with angular momentum exchange between orbital motion and disc rotation on a time scale which is considerably shorter than the corresponding Kelvin-Helmholtz time scale. Gravitational radiation losses are negligible in the evolution of EX Hya. Furthermore, the detection of a periodic modulation of the light curve with a period of 0.046546447 days and mean amplitudes between 0.2 and 0.4 magnitudes ('67-minute-cycle') is reported. This oscillation remained coherent over the 14 yr covered by observations. Either (1) asynchronous rotation or pulsations of the red component, (2) asynchronous rotation of the magnetic primary, or (3) resonances in the outer regions of the accretion disc are mentioned as possible sources for this periodicity.

Printing Options

Send high resolution image to Level 2 Postscript Printer
Send low resolution image to Level 2 Postscript Printer
Send low resolution image to Level 1 Postscript Printer
Get high resolution PDF image
Get low resolution PDF
Send 300 dpi image to PCL Printer
Send 150 dpi image to PCL Printer

More Article Retrieval Options

HELP for Article Retrieval
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
  New!

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints