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October 2004 IL Aqr/GJ 876 CampaignIL Aqr, known as GJ 876 in the exoplanet transit community, has two planets orbiting it. On October 21, 2004 the AAVSO will be conducting a ten-hour observing campaign to detect the largest of these planets, GJ 876b. Last updated: Wed Oct 27 13:36:50 EDT 2004 The main observing campaign is over. But we still need high-precision nightly observations through the end of the year.
Possible transit?
Day 1 (so far)
Day 2 (so far)
Day 3 (so far)
Campaign DetailsIntensive time series observation of IL Aqr/GJ 876 on October 21 is needed to detect a possible planetary transit. CCD observations unfiltered and in V are requested. The transit depth may be as much as 0.1 magnitude, but high precision is needed to look for possible anomalous behavior during the ingress and egress. Please practice on this field ahead of time and submit your observations to the AAVSO. Observing window: Transit Prediction: October 21 23:22 UT - 03:27 UT (Oct. 22) w/1 sigma uncertainty: October 21 18:22 UT - 08:27 UT (Oct. 22) w/3 sigma uncertainty: October 20 11:22 UT - 15:27 UT (Oct. 23) 
VRI image of IL Aqr/GJ 876 (the bright red one). Northeast is topleft. Image from Paddy McGee, of the University of Adelaide (used with permission). ParticipantsE-mail aaronp @ aavso.org to be added to this list. We need observers for the entire observing window, October 20 11:22 UT - October 23 15:27 UT and we need multiple observers per night.
Announcement(from CCD Views #326 - Oct 7, 2004) -------------------------------------------------------------------------- 1. EXOPLANET TRANSIT CAMPAIGN FOR IL AQR/GJ 867 The AAVSO has teamed up with transitsearch.org to coordinate an observing campaign for IL Aqr, a.k.a GJ 867 in the transit search community. Dr. Greg Laughlin, University of California at Santa Cruz, is looking for observations during an upcoming transit opportunity. IL Aqr is located at R.A.: 22:53:17.03 -14:15:52.5 The GJ 876 system contains two planets orbiting a nearby M-dwarf star. The planets are in an orbital resonance which leads to significant precession of their orbits. The causes the transits to be somewhat unpredictable and by observing the transits we can learn more about the orbital dynamics of the system. The purpose of the campaign is to detect transits of planet "b" if they are occuring, or to convincingly rule them out. Below are the transit windows: === Observations Transit Prediction: October 21 23:22 UT - October 22 03:27 UT w/3 sigma uncertainty: October 20 11:22 UT - October 23 15:27 UT ** Observations are needed during the entire 3 sigma window!! ** In addition, IL Aqr is a variable star that has not been well monitored. It has a tiny GCVS range of V=10.15-10.19, however that is just enough to interfere with transit detection. We need observations of IL Aqr to begin now so we can set a baseline of activity. Please begin observing IL Aqr at least once per night in B and V with as high precision as possible. Use the 119 comp star on the chart (B=12.956 +/- 0.033) and set your exposure for a good SNR. If possible, get a few time series runs in of at least four hours. Submit your data as soon as you can so we can evaluate IL Aqr's typical activity (so as not to confuse it with any transit activity). An e-scale chart has been created with 3 comparison stars from ASAS-3. It can be downloaded at: http://www.aavso.org/cgi-bin/searchcharts3.pl?name=il%20aqr The predicted transit depth *could* be relatively large, up to 0.1 magnitude. However detection of a transit is not assured, much less its amplitude! However, there is a catch. IL Aqr is a very red star so you need to use a filter, preferably a V filter. Also, be sure to use the star labelled 119 on the chart as your comp star and use the others as check stars. The 119 star is also red, but not as much, so it will provide more accurate photometry for untransformed observations. The 119's B magnitude is 12.956 +/- 0.033 . Observers should begin practicing on the object right now to make sure you can achieve the required level of precision. Try to get 0.01 mag precision to look for structure in the transit light curve. === Sign Up! Please observe as much as possible during the 3 days. We are creating a list on our web site of observers who can participate and during what windows they can observe. Please sign up by e-mailing aaronp@aavso.org with: Name, observer code, location, time zone and when you can observe. This will help us coordinate observations between observers. Weather has been a real challenge with prior observations of this object so we need multiple people observing from multiple locations around the globe. === Coordination A web page will be setup and maintained during the campaign: http://www.aavso.org/news/ilaqr.shtml The campaign will be coordinated via the web page and the AAVSO- Photometry Discussion Group. Visit the web page for links to the discussion group archives, updated light curves, progress reports, links to charts and more information. If you plan to participate in the campaign send us a note and we'll put you on the web page. During the campaign itself we may setup a chat server for observers to participate in. This transit would be of GJ 876b, the first (outer) planet discovered in the system. Details on the system and other transit results can be found at http://www.ucolick.org/~elaugh/GJ876____c.results.html The results of this transit will be combined with other transit results and research and submitted for publication. All observers who contribute significant photometry to this effort are welcome to be listed as co-authors of the manuscript. Note: IL Aqr was also the subject of Alert Notice #281 issued on May 11, 2001 and CCD Views Vol. 1 No. 1 for June, 2001. It can be read at this URL: http://www.aavso.org/publications/ccdviews/ccdviewsvol2no1.shtml If you have any unsubmitted data from those publications please submit them as soon as possible. They may be very valuable! ------------------------------------------------------------------------- |
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