English

A survey for variable stars with small telescopes: IX -- Evolution of Spot Properties on YSOs in IC5070

Solar and Stellar Astrophysics 2024-03-20 v1 Astrophysics of Galaxies

Abstract

We present spot properties on 32 periodic young stellar objects in IC 5070. Long term, \sim5 yr, light curves in the VV, RR, and II-bands are obtained through the HOYS (Hunting Outbursting Young Stars) citizen science project. These are dissected into six months long slices, with 3 months oversampling, to measure 234 sets of amplitudes in all filters. We fit 180 of these with reliable spot solutions. Two thirds of spot solutions are cold spots, the lowest is 2150 K below the stellar temperature. One third are warm spots that are above the stellar temperature by less than \sim2000 K. Cold and warm spots have maximum surface coverage values of 40 percent, although only 16 percent of warm spots are above 20 percent surface coverage as opposed to 60 percent of the cold spots. Warm spots are most likely caused by a combination of plages and low density accretion columns, most common on objects without inner disc excess emission in KW2K-W2. Five small hot spot solutions have <3<3 percent coverage and are 3000 - 5000 K above the stellar temperature. These are attributed to accretion, and four of them occur on the same object. The majority of our objects are likely to be accreting. However, we observe very few accretion hot spots as either the accretion is not stable on our timescale or the photometry is dominated by other features. We do not identify cyclical spot behaviour on the targets. We additionally identify and discuss a number of objects that have interesting amplitudes, phase changes, or spot properties.

Keywords

Cite

@article{arxiv.2403.10595,
  title  = {A survey for variable stars with small telescopes: IX -- Evolution of Spot Properties on YSOs in IC5070},
  author = {Carys Herbert and Dirk Froebrich and Siegfried Vanaverbeke and Aleks Scholz and Jochen Eislöffel and Thomas Urtly and Ivan L. Walton and Klaas Wiersema and Nick J. Quinn and Georg Piehler and Mario Morales Aimar and Rafael Castillo García and Tonny Vanmunster and Francisco C. Soldán Alfaro and Faustino García de la Cuesta and Domenico Licchelli and Alex Escartin Perez and Esteban Fernández Mañanes and Noelia Graciá Ribes and José Luis Salto González and Stephen R. L. Futcher and Tim Nelson and Shawn Dvorak and Dawid Moździerski and Krzysztof Kotysz and Przemysław Mikołajczyk and George Fleming and Mark Phillips and Tony Vale and Franky Dubois and Heinz-Bernd Eggenstein and Michael A. Heald and Pablo Lewin and Derek OKeeffe and Adam Popowicz and Krzysztof Bernacki and Andrzej Malcher and Slawomir Lasota and Jerzy Fiolka and Adam Dustor and Stephen C. Percy and Pat Devine and Aashini L. Patel and Matthew D. Dickers and Lord Dover and Ivana I. Grozdanova and James S. Urquhart and Chris J. R. Lynch},
  journal= {arXiv preprint arXiv:2403.10595},
  year   = {2024}
}

Comments

Accepted for publication by MNRAS. 17 + 7 pages, 7 + 23 figures, 1 table