Äîêóìåíò âçÿò èç êýøà ïîèñêîâîé ìàøèíû. Àäðåñ îðèãèíàëüíîãî äîêóìåíòà : http://www.mrao.cam.ac.uk/wp-content/uploads/2014/04/AHall.pdf Äàòà èçìåíåíèÿ: Wed Apr 16 17:16:43 2014 Äàòà èíäåêñèðîâàíèÿ: Sun Apr 10 13:22:29 2016 Êîäèðîâêà:

Neptunes in the Noise:
Improved Precision in Exoplanet Transit Detection
AimÈe Hall, Simon Hodgkin Institute of Astronomy, Cambridge
Anderson, D. R.; Armstrong, D.; Barros, S. C. C.; Brown, D.; Collier Cameron, A.; Doyle, A. P.; Faedi, F.; GÑmez Maqueo Chew, Y.; Haswell, C. A.; HÈbrard, G.; Hellier, C.; Lendl, M.; McCormac, J.; Norton, A. J.; Parley, N.; Pollacco, D.; Queloz, D.; Skillen, I.; Smalley, B.; Triaud, A. H. M. J.; P. J.; Udry, S.; Watson, C.; West, R. G.; Wheatley, P.


So many small exoplanets
A. W. Howard et al., Ap. J. S. 201 15 (2012)

Neptunes in the Noise

AimÈe Hall Institute of Astronomy, Cambridge


The ground is the limit?
Kepler All known

Neptunes in the Noise

AimÈe Hall Institute of Astronomy, Cambridge


The ground is the limit?
SuperWASP Kepler All known

Neptunes in the Noise

AimÈe Hall Institute of Astronomy, Cambridge


Brighter is better

Pont (2010, www.exoclimes.com)

Magnitude distribution of SuperWASP Planets
Neptunes in the Noise

Brighter stars better for atmospheric detection
AimÈe Hall Institute of Astronomy, Cambridge


SuperWASP
New Analysis
Co-located list driven photometry Soft-edged apertures Robust background estimator Seasonal Flatfields

Up to late 2011
Survey Mode 6 minute Cadence
Neptunes in the Noise

After late 2011
Stare Mode 1 minute Cadence
AimÈe Hall Institute of Astronomy, Cambridge


SuperWASP Archival Data
· · · · ·

There is a huge volume of archived SuperWASP data 3.2x1011 data points 30.8 million objects 10.6 million images (V=15) More than half of the observations span at least 4 years (up to 7) Mean of 15,000 epochs per star

Neptunes in the Noise

AimÈe Hall Institute of Astronomy, Cambridge


Noise reduction: Survey mode
New analysis Previous analysis Previous analysis + trend removal (SYSREM)

3mmag

Neptunes in the Noise

AimÈe Hall Institute of Astronomy, Cambridge


The colour of noise I - Survey Mode

Neptunes in the Noise

AimÈe Hall Institute of Astronomy, Cambridge


XO-5b Single Transit

Neptunes in the Noise

AimÈe Hall Institute of Astronomy, Cambridge


SuperWASP ­ Stare Mode
30 nights between Nov-Dec 2011

7 fields in this analysis
6000-14000 raw frames per field 70% of frames have suitable: · Average source ellipticity · Frame astrometric fit error · Seeing · Sky level · Zero point magnitude
Neptunes in the Noise

AimÈe Hall Institute of Astronomy, Cambridge


The colour of noise II ­ Stare Mode

2009 Survey Mode
2011 Stare Mode

Neptunes in the Noise

AimÈe Hall Institute of Astronomy, Cambridge


Planet Candidates
BLS search for potential transits Se · · · lected if: SNR > 8 More than 3 transits observed < 80% of transit data from 1 night

53 candidates have R < 2RJ Smallest candidate radius ~0.6RJ

Neptunes in the Noise

AimÈe Hall Institute of Astronomy, Cambridge


Example Candidates

Period: 0.31 days Depth ~3.5mmag
Neptunes in the Noise

Period: 1.68 days Depth ~6 mmag
AimÈe Hall Institute of Astronomy, Cambridge


Summary
We have developed and tested new processing strategies for SuperWASP:
· Reach 1-1.5mmag noise on archival SuperWASP data · Reach 1mmag noise on stare-mode SuperWASP data on transit duration timescales · Improved noise characteristics increase sensitivity to smaller planets and at longer periods · Lightcurves can tell blends from true planet candidates, saving follow-up resources

With just 30 nights we have 53 candidates with radii between 0.63 RJ and 2RJ

Window of opportunity to extend this analysis to the rest of the SuperWASP data to find planets for planet characterisation
Neptunes in the Noise

AimÈe Hall Institute of Astronomy, Cambridge