Time series photometric spot modelling

K. Oláh, K. G. Strassmeier, T. Granzer

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

We present spot models for nine years of continuous VIC photometry of UZ Lib from 1993-2001. The relatively stable double-humped light curve shape suggests extreme phase coherence. From the spot-modelling analysis, we found that the major spots or spot groups are always located on the hemisphere facing the secondary star and exactly in the opposite hemisphere anti-facing the secondary. Several single-humped light curves and our suggested binary scenario rule out a pure ellipsoidal variability as the cause of the double-humped light curve shape. We try to explain this preferred spot pattern with a magnetic-field structure that connects the two components, as suggested earlier for RS CVn stars in general. A possible 4.8 years spot cycle is found from the long-term brightness variations but needs confirmation. We rediscuss the basic astrophysical data of UZ Lib. The Hipparcos parallax is likely wrong, a possible reason could be that UZ Lib is e.g., a triple system.

Original languageEnglish
Pages (from-to)453-461
Number of pages9
JournalAstronomische Nachrichten
Volume323
Issue number5
DOIs
Publication statusPublished - 2002

Fingerprint

light curve
time series
hemispheres
modeling
stars
phase coherence
parallax
photometry
astrophysics
brightness
magnetic field
cycles
causes
magnetic fields
analysis
need

Keywords

  • Binaries: close
  • Stars: activity
  • Stars: individual (UZ Lib)
  • Stars: late-type
  • Stars: spots

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Time series photometric spot modelling. / Oláh, K.; Strassmeier, K. G.; Granzer, T.

In: Astronomische Nachrichten, Vol. 323, No. 5, 2002, p. 453-461.

Research output: Contribution to journalArticle

Oláh, K. ; Strassmeier, K. G. ; Granzer, T. / Time series photometric spot modelling. In: Astronomische Nachrichten. 2002 ; Vol. 323, No. 5. pp. 453-461.
@article{53a90546ebaf45098ca5ca090f7a87e0,
title = "Time series photometric spot modelling",
abstract = "We present spot models for nine years of continuous VIC photometry of UZ Lib from 1993-2001. The relatively stable double-humped light curve shape suggests extreme phase coherence. From the spot-modelling analysis, we found that the major spots or spot groups are always located on the hemisphere facing the secondary star and exactly in the opposite hemisphere anti-facing the secondary. Several single-humped light curves and our suggested binary scenario rule out a pure ellipsoidal variability as the cause of the double-humped light curve shape. We try to explain this preferred spot pattern with a magnetic-field structure that connects the two components, as suggested earlier for RS CVn stars in general. A possible 4.8 years spot cycle is found from the long-term brightness variations but needs confirmation. We rediscuss the basic astrophysical data of UZ Lib. The Hipparcos parallax is likely wrong, a possible reason could be that UZ Lib is e.g., a triple system.",
keywords = "Binaries: close, Stars: activity, Stars: individual (UZ Lib), Stars: late-type, Stars: spots",
author = "K. Ol{\'a}h and Strassmeier, {K. G.} and T. Granzer",
year = "2002",
doi = "10.1002/1521-3994(200210)323:5<453::AID-ASNA453>3.0.CO;2-Y",
language = "English",
volume = "323",
pages = "453--461",
journal = "Astronomische Nachrichten",
issn = "0004-6337",
publisher = "Wiley-VCH Verlag",
number = "5",

}

TY - JOUR

T1 - Time series photometric spot modelling

AU - Oláh, K.

AU - Strassmeier, K. G.

AU - Granzer, T.

PY - 2002

Y1 - 2002

N2 - We present spot models for nine years of continuous VIC photometry of UZ Lib from 1993-2001. The relatively stable double-humped light curve shape suggests extreme phase coherence. From the spot-modelling analysis, we found that the major spots or spot groups are always located on the hemisphere facing the secondary star and exactly in the opposite hemisphere anti-facing the secondary. Several single-humped light curves and our suggested binary scenario rule out a pure ellipsoidal variability as the cause of the double-humped light curve shape. We try to explain this preferred spot pattern with a magnetic-field structure that connects the two components, as suggested earlier for RS CVn stars in general. A possible 4.8 years spot cycle is found from the long-term brightness variations but needs confirmation. We rediscuss the basic astrophysical data of UZ Lib. The Hipparcos parallax is likely wrong, a possible reason could be that UZ Lib is e.g., a triple system.

AB - We present spot models for nine years of continuous VIC photometry of UZ Lib from 1993-2001. The relatively stable double-humped light curve shape suggests extreme phase coherence. From the spot-modelling analysis, we found that the major spots or spot groups are always located on the hemisphere facing the secondary star and exactly in the opposite hemisphere anti-facing the secondary. Several single-humped light curves and our suggested binary scenario rule out a pure ellipsoidal variability as the cause of the double-humped light curve shape. We try to explain this preferred spot pattern with a magnetic-field structure that connects the two components, as suggested earlier for RS CVn stars in general. A possible 4.8 years spot cycle is found from the long-term brightness variations but needs confirmation. We rediscuss the basic astrophysical data of UZ Lib. The Hipparcos parallax is likely wrong, a possible reason could be that UZ Lib is e.g., a triple system.

KW - Binaries: close

KW - Stars: activity

KW - Stars: individual (UZ Lib)

KW - Stars: late-type

KW - Stars: spots

UR - http://www.scopus.com/inward/record.url?scp=0036399213&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0036399213&partnerID=8YFLogxK

U2 - 10.1002/1521-3994(200210)323:5<453::AID-ASNA453>3.0.CO;2-Y

DO - 10.1002/1521-3994(200210)323:5<453::AID-ASNA453>3.0.CO;2-Y

M3 - Article

AN - SCOPUS:0036399213

VL - 323

SP - 453

EP - 461

JO - Astronomische Nachrichten

JF - Astronomische Nachrichten

SN - 0004-6337

IS - 5

ER -