The Probable Detecting of Surface Spots on AR Lacertae B

Kron, Gerald E.

doi:10.1086/125964

Cited by 81 publications

(49 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The variability seen in young, rapidly rotating stars has long been thought to be due to photospheric heterogeneities, such as magnetically induced starspots (for early discussions on spot induced brightness variations on active stars, see Pickering 1881;Kron 1947;Krzeminski 1969;Evans 1971). Therefore, by accurately measuring the period of their variability, we are able to sample the rotation-rate distribution of stars in Blanco 1.…”

Section: Periodic Variability In Blancomentioning

confidence: 99%

Evaluating Gyrochronology on the Zero-Age-Main-Sequence: Rotation Periods in the Southern Open Cluster Blanco 1 From the Kelt-South Survey

Cargile

James

Pepper

et al. 2014

ApJ

View full text Add to dashboard Cite

We report periods for 33 members of Blanco 1 as measured from Kilodegree Extremely Little Telescope-South light curves, the first reported rotation periods for this benchmark zero-age-main-sequence open cluster. The distribution of these stars spans from late-A or early-F dwarfs to mid-K with periods ranging from less than a day to ∼8 days. The rotation period distribution has a morphology similar to the coeval Pleiades cluster, suggesting the universal nature of stellar rotation distributions. Employing two different gyrochronology methods, we find an age of 146 +13 −14 Myr for the cluster. Using the same techniques, we infer an age of 134 +9 −10 Myr for the Pleiades measured from existing literature rotation periods. These rotation-derived ages agree with independently determined cluster ages based on the lithium depletion boundary technique. Additionally, we evaluate different gyrochronology models and quantify levels of agreement between the models and the Blanco 1/Pleiades rotation period distributions, including incorporating the rotation distributions of clusters at ages up to 1.1 Gyr. We find the Skumanich-like spin-down rate sufficiently describes the rotation evolution of stars hotter than the Sun; however, we find cooler stars rotating faster than predicted by a Skumanich law, suggesting a mass dependence in the efficiency of stellar angular momentum loss rate. Finally, we compare the Blanco 1 and Pleiades rotation period distributions to available nonlinear angular momentum evolution models. We find they require a significant mass dependence on the initial rotation rate of solar-type stars to reproduce the observed range of rotation periods at a given stellar mass and are furthermore unable to predict the observed over-density of stars along the upper envelope of the clusters' rotation distributions.

show abstract

Section: Periodic Variability In Blancomentioning

confidence: 99%

Evaluating Gyrochronology on the Zero-Age-Main-Sequence: Rotation Periods in the Southern Open Cluster Blanco 1 From the Kelt-South Survey

Cargile

James

Pepper

et al. 2014

ApJ

View full text Add to dashboard Cite

show abstract

“…In the middle of the last century it was realised that certain observed features of late-type stars could be explained by magnetic phenomena (Kron 1947), similar to those detected on the Sun. The cyclic pattern of solar activity had already been known for more than 120 years (Schwabe 1843) by the time systematic research of the magnetic activity of late-type stars commenced.…”

Section: Introductionmentioning

confidence: 96%

Multiple and changing cycles of active stars

Oláh¹,

Kollath²,

Granzer

et al. 2009

A&A

193

216

View full text Add to dashboard Cite

Aims. We study the time variations in the cycles of 20 active stars based on decade-long photometric or spectroscopic observations. Methods. A method of time-frequency analysis, as discussed in a companion paper, is applied to the data. Results. Fifteen stars definitely show multiple cycles, but the records of the rest are too short to verify a timescale for a second cycle. The cycles typically show systematic changes. For three stars, we found two cycles in each of them that are not harmonics and vary in parallel, indicating a common physical mechanism arising from a dynamo construct. The positive relation between the rotational and cycle periods is confirmed for the inhomogeneous set of active stars. Conclusions. Stellar activity cycles are generally multiple and variable.

show abstract

“…Numerous papers dealt with this phenomenology since the early seventies, starting with the first interpretations by Kron (1947Kron ( , 1952, Hoffmeister (1965), Chugainov (1966), Catalano & Rodonó (1967) and Hall (1972) and finally culminating in the use of fully automatic telescopes for continuously monitoring RS CVn-and even solar-type stars (e.g. Henry et al 1995a).…”

Section: Introduction: Starspot Photometrymentioning

confidence: 99%

Starspot photometry with robotic telescopes

Strassmeier¹,

Bartus²,

Cutispoto

et al. 1997

Astron. Astrophys. Suppl. Ser.

117

145

View full text Add to dashboard Cite

Abstract. We report on the progress of our ongoing photometric monitoring program of spotted late-type stars with automatic photoelectric telescopes (APTs) on Mt. Hopkins in Arizona and on Mt. Etna in Sicily. We present 9 250 differential UBV and/or V (RI) C observations for altogether 23 chromospherically active stars, singles and binaries, pre main sequence and post main sequence, taken between 1991 and 1996. The variability mechanism of our target stars is mostly rotational modulation by an asymmetrically spotted stellar surface. Therefore, precise rotational periods and their seasonal variations are determined using baselines between 3 years for HD 129333 to 34 years for V410 Tauri. We report the largest V light-curve amplitude of any spotted star observed to date: 0.m 65 for V410 Tau in 1994-95. Long-term variations of the overall light levels of our target stars are sometimes of similar amplitude as the rotational modulation itself and are most likely caused by an analog of the solar 11-year spot cycle but mostly without a well-defined periodicity. For some of our target stars (HD 12545, HD 17433, EI Eri, V410 Tau, LQ Hya, and HD 106225) we estimate a probable cycle period. A complete light curve of the semi-regular S-type giant HR Pegasii is presented. All data are available via the WorldWideWeb 1 .

show abstract

The Probable Detecting of Surface Spots on AR Lacertae B

Cited by 81 publications

References 0 publications

Evaluating Gyrochronology on the Zero-Age-Main-Sequence: Rotation Periods in the Southern Open Cluster Blanco 1 From the Kelt-South Survey

Evaluating Gyrochronology on the Zero-Age-Main-Sequence: Rotation Periods in the Southern Open Cluster Blanco 1 From the Kelt-South Survey

Multiple and changing cycles of active stars

Starspot photometry with robotic telescopes

Contact Info

Product

Resources

About