Noise properties of the CoRoT data. A planet-finding perspective
Suzanne Aigrain
(1)
,
Frédéric Pont
(1)
,
Francois Fressin
(2)
,
A. Alapini
(1)
,
Roi Alonso
(3)
,
Michel Auvergne
(4)
,
Mauro Barbieri
(3)
,
Pierre Barge
(3)
,
P. Bordé
(5)
,
François Bouchy
(6)
,
Hans J. Deeg
(7)
,
R. de la Reza
(8)
,
Magali Deleuil
(3)
,
Rudolf Dvorak
(9)
,
Anders Erikson
(10)
,
Malcolm C. Fridlund
(11)
,
Philippe Gondoin
(11)
,
P. Guterman
(3)
,
Laurent Jorda
(3)
,
Helmut Lammer
(12)
,
Alain Léger
(5)
,
Antoine Llebaria
(3)
,
Pierre Magain
(13)
,
Tsevi Mazeh
(14)
,
Claire Moutou
(3)
,
Marc Ollivier
(5)
,
M. Pätzold
(15)
,
Didier Queloz
(16)
,
Heike Rauer
(10)
,
Daniel Rouan
(4)
,
Jean Schneider
(17)
,
G. Wuchter
(18)
,
S. Zucker
(14)
1
University of Exeter
2 CfA - Harvard-Smithsonian Center for Astrophysics
3 LAM - Laboratoire d'Astrophysique de Marseille
4 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
5 IAS - Institut d'astrophysique spatiale
6 OHP - Observatoire de Haute-Provence
7 IAC - Instituto de Astrofisica de Canarias
8 Observatório Nacional/MCTI
9 IfA - Institut für Astronomie, Universität Wien
10 DLR Institut für Planetenforschung
11 RSSD - Research and Scientific Support Department, ESA-ESTEC
12 ÖAW - Osterreichische Akademie der Wissenschaften = Académie autrichienne des sciences
13 Université de Liège
14 TAU - Tel Aviv University
15 RIU - Rheinisches Institut für Umweltforschung
16 ObsGE - Observatoire Astronomique de l'Université de Genève
17 LUTH (UMR_8102) - Laboratoire Univers et Théories
18 Thüringer Landessternwarte, Tautenburg Observatory
2 CfA - Harvard-Smithsonian Center for Astrophysics
3 LAM - Laboratoire d'Astrophysique de Marseille
4 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
5 IAS - Institut d'astrophysique spatiale
6 OHP - Observatoire de Haute-Provence
7 IAC - Instituto de Astrofisica de Canarias
8 Observatório Nacional/MCTI
9 IfA - Institut für Astronomie, Universität Wien
10 DLR Institut für Planetenforschung
11 RSSD - Research and Scientific Support Department, ESA-ESTEC
12 ÖAW - Osterreichische Akademie der Wissenschaften = Académie autrichienne des sciences
13 Université de Liège
14 TAU - Tel Aviv University
15 RIU - Rheinisches Institut für Umweltforschung
16 ObsGE - Observatoire Astronomique de l'Université de Genève
17 LUTH (UMR_8102) - Laboratoire Univers et Théories
18 Thüringer Landessternwarte, Tautenburg Observatory
François Bouchy
- Fonction : Auteur
- PersonId : 755523
- ORCID : 0000-0002-7613-393X
- IdRef : 069924120
P. Guterman
- Fonction : Auteur
- PersonId : 1126595
- ORCID : 0000-0001-7846-7530
- IdRef : 10204743X
Claire Moutou
- Fonction : Auteur
- PersonId : 1156835
- IdHAL : claire-moutou
- ORCID : 0000-0002-2842-3924
- IdRef : 10151218X
Résumé
In this short paper, we study the photometric precision of stellar light curves obtained by the CoRoT satellite in its planet-finding channel, with a particular emphasis on the time scales characteristic of planetary transits. Together with other articles in the same issue of this journal, it forms an attempt to provide the building blocks for a statistical interpretation of the CoRoT planet and eclipsing binary catch to date. After pre-processing the light curves so as to minimise long-term variations and outliers, we measure the scatter of the light curves in the first three CoRoT runs lasting more than 1 month, using an iterative non-linear filter to isolate signal on the time scales of interest. The behaviour of the noise on 2 h time scales is described well by a power-law with index 0.25 in R-magnitude, ranging from 0.1 mmag at R=11.5 to 1 mmag at R=16, which is close to the pre-launch specification, though still a factor 2-3 above the photon noise due to residual jitter noise and hot pixel events. There is evidence of slight degradation in the performance over time. We find clear evidence of enhanced variability on hour time scales (at the level of 0.5 mmag) in stars identified as likely giants from their R magnitude and B-V colour, which represent approximately 60 and 20% of the observed population in the directions of Aquila and Monoceros, respectively. On the other hand, median correlated noise levels over 2 h for dwarf stars are extremely low, reaching 0.05 mmag at the bright end.