Volume 506, Number 1, October IV 2009
The CoRoT space mission: early results
|Page(s)||425 - 429|
|Published online||16 April 2009|
Noise properties of the CoRoT data*
A planet-finding perspective
School of Physics, University of Exeter, Exeter, EX4 4QL, UK e-mail: firstname.lastname@example.org
2 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, US
3 LAM, Université de Provence, 13388 Marseille, France
4 LESIA, Observatoire de Paris, 92195 Meudon, France
5 IAS, Université Paris XI, 91405 Orsay, France
6 Observatoire de Haute-Provence, 04870 St Michel l'Observatoire, France
7 IAC, 38205 La Laguna, Spain
8 ON/MCT, 20921-030, Rio de Janeiro, Brazil
9 IfA, University of Vienna, 1180 Vienna, Austria
10 Institute of Planetary Research, DLR, 12489 Berlin, Germany
11 RSSD, ESA/ESTEC, 2200 Noordwijk, The Netherlands
12 IWF, Austrian Academy of Sciences, 8042 Graz, Austria
13 IAG, Université de Liège, Liège 1, Belgium
14 Sch. Physics & Astronomy, Tel Aviv Univ., Tel Aviv 69978, Israel
15 RIU, Universität zu Köln, 50931 Köln, Germany
16 Observatoire de Genève, 1290 Sauverny, Switzerland
17 ZAA, TU Berlin, 10623 Berlin, Germany
18 LUTH, Observatoire de Paris, 92195 Meudon, France
19 Thüringer Landessternwarte, 07778 Tautenburg, Germany
20 Dept. Geophysics & Planetary Sciences, Tel Aviv Univ., Tel Aviv 69978, Israel
Accepted: 9 March 2009
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 to 1 mmag at , 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 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.
Key words: methods: data analysis / techniques: photometric / stars: planetary systems
The CoRoT space mission, launched on December 27, 2006, has been developed and is operated by the CNES, with the contribution of Austria, Belgium, Brazil, ESA, Germany, and Spain. CoRoT data become publicly available one year after release to the Co-Is of the mission from the CoRoT archive: http://idoc-corot.ias.u-psud.fr/.
© ESO, 2009
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