Massive Search for Spot- and Facula-Crossing Events in 1598 Exoplanetary Transit Light Curves
R.V. Baluev1,
E.N.Sokov2,1,
I.A. Sokova2,1,
V.Sh. Shaidulin1,
A.V. Veselova1,
V.N. Aitov3,
G.Sh. Mitiani3,
A.F. Valeev3,4,
D.R. Gadelshin3,
A.G. Gutaev3,5,
G.M. Beskin3,5,
G.G. Valyavin3,4,1,
K. Antonyuk4,
K. Barkaoui6,7,
M. Gillon6,
E. Jehin8,
L. Delrez6,8,
S. Guðmundsson9,
H.A. Dale10,
E. Fernández-Lajús11,12,
R.P. Di Sisto11,12,
M. Bretton13,
A. Wunsche13,
V.-P. Hentunen14,
S. Shadick15,
Y. Jongen16,
W. Kang17,
T. Kim17,18,
E. Pakštienė19,
J.K.T. Qvam20,
C.R. Knight21,
P. Guerra22,
A. Marchini23,
F. Salvaggio23,
R. Papini23,
P. Evans24,
M. Salisbury25,
J. Garlitz26,
N. Esseiva27,
Y. Ogmen28,
P. Bosch-Cabot29,
A. Selezneva29 and
T.C. Hinse30,31
1Saint Petersburg State University, 7--9 Universitetskaya Emb., St Petersburg 199034, Russia
2Central Astronomical Observatory at Pulkovo of Russian Academy of Sciences, Pulkovskoje sh. 65/1, St Petersburg 196140, Russia
3Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhyz, 369167, Russia
4Crimean Astrophysical Observatory, Russian Academy of Sciences, Nauchny, 298409, Russia
5Kazan (Volga Region) Federal University, Kazan, 420008, Russia
6Astrobiology Research Unit, Universitè de Liège, Alleè du 6 Août 19C, B-4000 Liège, Belgium
7Oukaimeden Observatory, High Energy Physics and Astrophysics Laboratory, Cadi Ayyad University, Marrakech, Morocco
8Space Sciences, Technologies and Astrophysics Research (STAR) Institute, Universitè de Liège, Allèe du 6 Août 19C, B-4000 Liège, Belgium
9Nes Observatory, Hraunholl 5, 781 Hornafjörður, Southeast Iceland
10Emory University Department of Physics, 400 Dowman Drive, Suite N201, Atlanta, GA 30322
11Facultad de Ciencias Astronómicas y Geofísicas - Universidad Nacional de La Plata, Paseo del Bosque S/N - 1900 La Plata,
Argentina
12Instituto de Astrofísica de La Plata (CCT La Plata - CONICET/UNLP), Argentina
13Baronnies Provençales Observatory, Hautes Alpes - Parc Naturel Règional des Baronnies Provençales, F-05150 Moydans, France
14Taurus Hill Observatory, Warkauden Kassiopeia ry., Härkämäentie 88, 79480 Kangaslampi, Finland
15Physics and Engineering Physics Department, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan,
S7N 5E2, Canada
16Observatoire de Vaison la Romaine, 1075 RD 51, Le Palis, 84110 Vaison-la-Romaine, France
17National Youth Space Center, Goheung, Jeollanam-do, 59567, South Korea
18Department of Astronomy and Space Science, Chungbuk National University, Cheongju-City, 28644, South Korea
19Institute of Theoretical Physics and Astronomy, Vilnius University, Sauletekio al. 3, Vilnius 10257, Lithuania
20Horten Videregående Skole, Strandpromenaden 33, 3183 Horten, Norway
21Ngileah Observatory, 144 Kilkern Road, RD 1. Bulls 4894, New Zealand
22Observatori Astronómic Albanyà, Camí de Bassegoda s/n, 17733 Albanyà, Spain
23Astronomical Observatory, DSFTA - University of Siena, Via Roma 56, 53100 -- Siena, Italy
24El Sauce Observatory, Coquimbo Province, Chile
25School of Physical Sciences, The Open University, Milton Keynes, MK7 6AA, UK
26AAVSO, Private Observatory, Elgin, OR 97827, USA
27Observatory Saint Martin, code k27, Amathay Vesigneux, France
28Green Island Observatory, Code B34, Gecitkale, Famagusta, North Cyprus
29Observatori Astronómic Albanyà, 17733 Albanyà, Girona, Spain
30Institute of Astronomy, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Toruń, Poland
31Chungnam National University, Department of Astronomy, Space Science and Geology, Daejeon, South Korea
Received: March 15, 2021
ABSTRACT
We developed a dedicated statistical test for a massive detection of
spot- and facula-crossing anomalies in multiple exoplanetary transit
light curves, based on the frequentist p-value thresholding. This
test was used to augment our algorithmic pipeline for transit light
curves analysis. It was applied to 1598 amateur and professional
transit observations of 26 targets being monitored in the EXPANSION
project. We detected 109 statistically significant candidate events
revealing a roughly 2:1 asymmetry in favor of spots-crossings over
faculae-crossings. Although some candidate anomalies likely appear
non-physical and originate from systematic errors, such asymmetry
between negative and positive events should indicate a physical
difference between the frequency of star spots and faculae. Detected
spot-crossing events also reveal positive correlation between their
amplitude and width, possibly due to spot size
correlation. However, the frequency of all detectable crossing
events appears just about a few per cent, so they cannot explain
excessive transit timing noise observed for several targets.
Key words:
Planetary systems - Techniques: photometric - starspots
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