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December 6, 2009:

Transitsearch.org is back online. We'll be introducing a number of new functionalities for the site quite soon, so stay tuned! Also, get ready for the transit of HD 80606b, which will be occurring Jan 13/14 2010. Transitsearch.org will be coordinating a flotilla of ground and space-based observations of the events surrounding the next '606 day.

April 05, 2009:

Transitsearch is now on Twitter. Visit http://twitter.com/Transitsearch. We'll be using this medium to provide updates on observing campaigns, new site functionalities, improvements to the ephemeris tables, and catty comments about celebrities.

March 30, 2009:

An improved orbital model has been derived for HD 28185b, a giant planet orbiting in the habitable zone of its host star. A long-shot observing campaign is being encouraged to check for transits by this planet (Aug 2009 is the next opportunity) in the hope of striking it lucky, and then following up to discover a habitable moon. See scenario one at oklo.org for more details.

March 29, 2009:

During February and March 2009, there was a revival of interest in the possibility that HD 68988 b can be observed in transit. It now appears extremely unlikely, however, that transits occur. Joao Gregorio (Portugal) and Bruce Gary (Arizona) observed HD 68988 on March 28/29 and were able to generate a assembled a composite 9-hour light curve that shows no sign of transit. This approach shows the power of multi-observer campaigns on a single target of interest. Bruce Gary has maintained a detailed discussion of the campaign on the AXA website.

March 28, 2009:

We have begun an ongoing review of the transitsearch.org candidate list in an effort to (1) verify that the transit prediction tables are as accurate as possible, and to (2) populate the candidate results pages with up-to-date information. To start, we have updated our orbital fits to the planets orbiting HD 86081, HD 33283, and HD 224693. The later two candidates (with orbital periods of 18.19d and 26.70d respectively) have never been checked for transits, and therefore make prime candidates for Transitsearch.org observers.

February 28, 2009:

HD 80606b has been detected in transit! This discovery has been reported independently by Moutou et al. (2009), Fossey et al. (2009) and Garcia-Melendo (2009). Amateur observers Alessandro Marchini from Siena, Tuscany, and Giorgio Corfini, from Lucca, Tuscany also obtained discovery photometry that shows the transit. For details of the discovery and the search, see the articles from late January 2009 through early March 2009 at oklo.org.

January 05, 2009:

Veli-Pekka Hentunen and Markku Nissinen of Varkaus Finland carried out confirmation observations of the recently discovered transiting planet WASP-12. their work showed that a misprint had been propagated into the original discovery paper ephemeris for the planet. As a result of their work, this error has now been corrected in the literature. For more details, see the discussion at the AXA. The table of upcoming transits for WASP-12 is based on the corrected ephemeris. For more information on the highly unusual planet WASP-12, see this article on oklo.org.

September 17, 2008:

Transitsearch operations are being shifted to the NStED exoplanet database. Until the transfer is complete, we'll continue to update the candidates table. Most recent additions include: Gl 832b, Gl 849b, HD11506b, HD 90647b, HD 205739b, HD 221287b, HD 23127b, HD 285968b, HD 50499b, HD 5319b, and HD 70642b.

April 04, 2008:

An intensive campaign by small telescope observers is significantly improving our understanding of the Gliese 436 planetary system. In May 2007, Gillon et al. discovered that Gliese 436 b, a Neptune-mass planet that had been discovered by the radial velocity technique, is observable in transit. In January 2008, a paper by Ribas et al. suggested that then-current radial velocity observatons were consistent with a perturbing 5-Earth mass second planet. Ribas et al. showed that transit timing observations would be able to confirm or rule out the existence of this planet. Bruce Gary has collected observations from a number of individual observers. His analysis indicates that there is currently no firm evidence for the proposed second planet. More observations of Gl 436 transits are encouraged.

January 15, 2008:

Transitsearch has partnered with Bruce Gary's Amateur Exoplanet Archive (AXA) to provide a database of observations taken by small-telescope observers of candidate transit-bearing stars. For more information, please see here at the AXA.

November 24, 2007:

HD 80606b has the most eccentric orbit of any known exoplanet. On November 20th, the Spitzer Space Telescope observed HD 80606 during the planet's periastron passage. By measuring how fast the planet heats up in response to the intense irradiation from the star, we can gain insight into the atmospheric properties.

Opportunity to catch the planet in transit comes six days after the periastron passage. The chance of observing a transit is small (~1.6%) but it's nevertheless worthwhile to verify that transits are not occuring. HD 80606b was the subject of a previous transitsearch.org campaign which covered some, but not all, of the transit window. Observers are encouraged to monitor the star from Nov. 25-27th. For observing details see here, for ephemeris see the transitsearch.org candidates page.

October 29, 2007:

A new paper by the Geneva Extrasolar Search Team (published on astro-ph yesterday) announces the discovery of highly eccentric planets orbiting the sunlike stars HD 156846 and HD 4113. The newly discovered planets have orbital periods of 359.5 and 526.6 days, and eccentricities, e=0.847 and e=0.903, respectively. Normally, planets with such long periods make poor Transitsearch.org candidates, due low a-priori transit probabilities and highly uncertain transit windows. This, however, is not the case for HD 156846. The periastron angle for this planet's orbit is reasonably well aligned with the line of sight to Earth, which increases the transit probability to a respectable 3.6%. The transit window is also quite well determined. The next opportunity occurs on Sept. 09, 2008. Save the date!

October 21, 2007:

To date, all of the known extrasolar planets transiting bright parent stars are north of the celestial equator! Follow-up photometric campaigns are therefore needed from Transitsearch.org observers in the Southern Hemisphere, and we will be promoting individual opportunities as they arise. One planet of interest is HD 76700b. Radial Velocity data published by the California-Carnegie and AAT planet search teams have allowed a re-estimation of the observing windows for this planet, which has an a-priori transit probability of 10% and an orbital period of 3.971 d.

For more details, see the results page for HD 76700 on the Transitsearch candidates table.

October 04, 2007:

Transits of HD 17156b have been confirmed.

The Sep. 9/10, 2007 transit of HD 17156 was observed by Transitsearch.org participants C. Lopresti and D. Gasparri from Italy, and by J. Almenara of the IAC in the Canary Islands. Analysis of the data was led by M. Barbieri and R. Alonso of LAM, Marseille, France.

On Sep 30/ Oct 1, the transit was confirmed by W. Welsh, A. Rajan, J. Irwin, P. Nutzman, and D. Charbonneau, and by Transitsearch.org participant D. Davies. A discovery paper, Barbieri et al. 2007 (157 KB) has been submitted for publication in the journal Astronomy and Astrophysics. With an orbital period of 21.22 days and an orbital eccentricity of e=0.67, HD 17156b has both the longest period and highest eccentricity of any known transiting extrasolar planet. It is also the first transit to be discovered under the auspices of Transitsearch.org.

Here are the discovery observations:

Discovery Photometry of the HD 17156b transit

Here is a to-scale figure showing the orbit, the planet (at equally spaced intervals in time) and the parent star. The transits occur fairly close to the moment of periastron passage, when one hemisphere of the planet is receiving a maximal amount of heating:

hd17156 orbit

September 19, 2007:

Initial results from the recent Transitsearch campaign on HD 17156 are encouraging. Jose Manuel Almenara Villa, observing from the Canary Islands, obtained a time-series that is consistent with a transit by HD 17156 b at the predicted time. The weather, however, was not optimal on the night of observation, and so follow-up observations are highly encouraged. The next transit opportunity occurs on the night of Sep 30/Oct 1, and is best observed from North America. For more details, see this post at oklo.org.

September 08, 2007:

Endl et al. have published a preprint describing the discovery of a Neptune-mass planet orbiting the nearby red dwarf star Gliese 176 (aka HD 285968). The new planet has an orbital period of 10.24 days, an a-priori transit probability of 3%, and an expected transit depth of 0.4%. This is a low-amplitude signal, but it is nevertheless accessible to many experienced amateur astronomers. The discovery paper makes no mention of a photometric transit search, making this planet a very attractive Transitsearch candidate. The star is located at RA 04:43, Dec +18:57, and the next transit window is centered on Sep. 15, 2007. We recommend obtaining photometry within 48 hours of either side of the nominal transit center. A full list of transit windows is located on the Transitsearch.org candidates page.

September 03, 2007:

Transitsearch observers are encouraged to obtain photometry of the planet-bearing star HD 17156 during upcoming transit windows. As described in this article on the systemic web log, HD 17156 b presents one of the best opportunities yet for Transitsearch observers to discover a new transit.

August 27, 2007:

Bruce Gary is an experienced observer of transiting extrasolar planets, and is a member of the XO network, which has had made several discoveries of new transiting planets (see e.g. here). Bruce has written a book, Exoplanet Observing for Amateurs which he's made available for free in .pdf form.

In other news, Transitsearchers should pay close attention to HD 17156b (see the transitsearch.org candidates page). This planet is on a highly eccentric 22-day orbit, and the geometry of the orbit is very well-suited for potential transits. The a-priori geometric probability of transit is a respectable 11%, and its high declination (+71 deg) makes it an ideal target for Northern Hemisphere observers.

August 9, 2007:

The Transitsearch.org candidates page has been updated to include the transit ephemerides of TrES-4, a bizarrely over-inflated planet that was announced this week. It is possible that TrES-4 large size is due to ongoing circularization of an eccentric orbit. If this is the case, then it's likely that there is a significant perturbing companion planet in the system. It's worthwhile to keep the TrES-4 parent star under photometric observation in order to possibly detect a transit by the unseen "planet X". And as always, visit oklo.org for the latest extrasolar planet news.

July 27, 2007:

We've made additional updates to the transitsearch.org candidates page, including the newly discovered transiting planet HAT-P-3b, and we've also introduced an unpublished candidates page for photometric follow-up of potential planets detected by the systemic collaboration.

June 7, 2007:

We've made a number of improvements to the code that updates the ephemeris tables on the transitsearch.org candidates page. The code now incorporates the latest information for known transiting planets (see here), and has been signficantly updated with the latest orbital fits for systems that are not known to transit.

June 3, 2007:

Transitsearch.org is currently teaming with the AAVSO to run a follow-up campaign on the newly discovered transiting Neptune-sized planet orbiting the red dwarf Gliese 436. More details will be announced shortly. As always, please refer to the Systemic project at oklo.org for the latest news on exoplanet resarch and transit detection.

December 15, 2006:

The results of a transitsearch.org campaign (led by CDR Paul Shankland of the United States Naval Observatory) to check for transits of the two outer planets orbiting the red dwarf Gl 876 have been published in the Astrophysical Journal. This refereed article includes 9 transitsearch.org observers as co-authors. Here are links to the ADS abstract, and to the pre-print on astro-ph. Shankland has taken the lead on photometric monitoring of nearby red dwarfs to search for transits of low-mass planets. Follow this link to his GEMSS project website.

April 16, 2006:

Transitsearch.org observers have ruled out the occurrence of transits of the Neptune-mass planet orbiting the nearby red dwarf Gl 581. See here for the results, and here and here for the background on the campaign.

Dec. 9, 2005:

Transitsearch.org is collaborating on a new Southern Hemisphere campaign on the star HD 13445 (Also known as GL 86b). This star is accompanied by a massive planet on a 15.8 day orbit. The AAVSO will provide a data collection and light curve analysis facility for this campaign. The campaign is being coordinated by Dr. David Blank (david dot blank at symbol jcu dot edu dot au) of James Cook University in Australia. Blank has written up a short campaign circular (.pdf format). The AAVSO have posted information on the campaign here.

Dec. 6, 2005:

Please visit our new extrasolar planets site at www.oklo.org. This site contains the latest transitsearch.org news and a discussion forum. Oklo.org is also the home base for both the new systemic collaboration and the Systemic Console. Systemic, to be launched in early 2006, is a public participation research project aimed at providing a better charactization of the statistical distribution of extrasolar planets.

Apr. 21, 2005:

Transitsearch.org is coordinating an extensive photometric campaign on the parent star of the recently discovered transiting planet TrES-1. The first goal of this campaign is to determine whether brightness variations occur during the periods before, during, and after transit. The second campaign goal is to develop a reporting and analysis framework for simultaneous multi-telescope observations of a single event. This campaign is being coordinated by Ron Bissinger, and is described in detail in his campaign circular. Further information can be found on the transitsearch.org TrES-1 results page.

Feb. 17, 2005:

Transitsearch.org and the AAVSO announce a photometric campaign to check for a planetary transit by the highly eccentric planet HD 80606b. The transit window occurs from Feb 24-Feb 26 2005. Details about the transit opportunity are given in this .pdf file, on the HD 80606 results page of the transitsearch.org candidates site, and at the AAVSO campaign webpage.

Feb. 16, 2005:

No sign of a transit was found for HD 74156 or HD 37605. (see campaign website) While coverage of these stars was quite good during the transit campaign of late December 2004, transits have not yet been definitively ruled out. Observers (especially Southern Hemisphere Observers not participating the the HD 80606b campaign) are thus urged to obtain photometry of the stars during the upcoming window from Feb 19-23, 2005.

Dec. 3, 2004:

Transitsearch.org and the American Association of Variable Star Observers announce a worldwide photometric campaign to check for planetary transits of HD 74156 and HD 37605 during the end of December 2004 and during the beginning of January 2005. A general overview of the campaign is given at the Sky and Telescope Website. Detailed information for observers, including a discussion group, observing techniques, coordinates, baseline photometry, and sky charts are available at the AAVSO campaign website. The scientific justification for this campaign and other technical details are given in a campaign circular downloadable here as a .pdf file.

Nov. 15, 2004:

The UC-Carnegie Planet Search Team has obtained a refined radius measurement of 1.08 Rjup of the transiting planet TrES-1. Uncertainty in the determination of the radius was reduced by combining transit photometry taken on Sep. 1, 2004 and Sep 4, 2004 by Transitsearch.org and CBA Belgium observer Tonny Vanmunster with high-resolution stellar spectra and radial velocities obtained in late August 2004 at Keck Observatory. The paper (downloadable here in preprint form) has been accepted for publication in the Astrophysical Journal.

Oct. 29, 2004:

Transitsearch.org observer Ron Bissinger has completed a detailed bootstrap Monte-Carlo analysis of multiple TrES-1 light curves obtained by transitsearch.org observers. His analysis (downloadable here in .pdf form 3.2 MB) suggests that the pre-ingress and post-egress features that have been noted in many of the TrES-1 light curves may have statistical significance. If these features are real, they should be confirmed by HST observations of TrES-1 scheduled starting in Nov. 2004.

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