WASP3-b daje szanse na nowe odkrycie dla amatorów.

[Hans]

Cześć,

 

Wyniki TTV dla WASP-3b sugerują obecność drugiej planety pozasłonecznej w układzie WASP3. Różnice w wynikach czasów rejestrowanych środków tranzytu dochodzą do 3, 4 minut. Spokojnie możemy łapać to sami. O czym dokładnie mowa możecie znaleźć w kilku miejscach. Dosyć przystępnie idea opisana jest na AP - http://forum.astropolis.pl/topic/27553-exomoons-nowa-ziemia-w-zasigu-amatora/

 

 

Poniżej pełna treść prośby o obserwacje. Masz okazję dołożyć cegiełkę do odkrycia nowej egzoplanety.

 

Pozdrawiam.

 

Exoplanet Observers,*Subject #1*This is a "call for observations" of WASP-3b transits. A recent publication by Maciejewski et al, http://arxiv.org/abs/1006.1348, suggests that a Transit Timing Variation (TTV) is present with a periodicity corresponding to a second exoplanet in an outer 2:1 orbit. The peak-to-peak variation is ~ 3 or 4 minutes, so this signal should be observable by amateurs. The above paper used only professional observations, consisting or 14 mid-transit times. There are more than 28 amateur observations in the AXA and ETD archives, so to see if this data would "strengthen the case" for the suggested TTV signal I performed an analysis of the 21 best quality amateur mid-transit times. I concluded that the amateur data, like the professional data, are "suggestive" but not conclusive in detecting an approximate 2:1 TTV periodicity (~ 3.75 days). You can find a description of my analysis at the AXA web page for WASP-3b: http://brucegary.net/AXA/WASP3/wasp3.htmJuly is the best observing season for WASP-3, so even though the nights are short this target is observable all night. Please submit light curve observations of transits to the ETD.*Subject #2*On a somewhat related subject, I want to express caution about reporting observations in terms of HJD. I will never again use HJD (based on UTC time standard) because it has shortcomings that are easily overcome by using BJD (based on either the TT or TDB time standards). BJD stands for Barycentric Julian Date, which uses the solar system's center-of-mass for a reference frame. HJD, or Heliocentric Julian Date, uses the sun's center for a reference frame, and because of gravitational effects of Jupiter, Saturn and the other planets the sun-center follows a wobbling path corresponding to +/- 4 seconds of light travel time. That means that comparing two mid-transit times using HJD could produce an error of as much as 8 seconds! Another improvement in reporting observations is to convert UTC to a time standard that doesn't have 1-second discontinuities whenever leap second adjustments are made (typically once a year). The two most common time standards that overcome this are TAI (International Atomic Time) and TT (Terrestial Time). TAI is obtained by adding the accumulation of leap seconds since they were started (currently 34 seconds), and TT is obtained by adding an additional 32.2 seconds (to make it consistent with a time standard used decades ago by solar system dynamics people). An even more accurate time standard is TDB (Barycentric Dynamical Time), which is usable when accuracies of microseconds are needed (something pulsar people need). We don't need microsecond accuracy, but it's easier to get (from an on-line converter web page) than TT. There is merit in reporting an astronomical event, such as a mid-transit time, in terms of when it would be observed by someone "living" at the solar system's center-of-mass with a perfect clock, and calculating this is now quite simple! Here's what you do:1) be sure to set your computer clock before observing (using any of the internet clock-setting programs; I think they all set to UTC),2) Check that your photometrically-processed data file has JD time tags corresponding to middle of exposure (this is what MaxIm DL does for its CSV-files). If not, be sure to figure out a way to alter the time tags before fitting the data and solving for mid-transit time (or submitting them to ETD).3) Copy the mid-transit time JD (using UTC time standard) and paste it in the input window of the on-line converter web site: http://astroutils.astronomy.ohio-state.edu/time/utc2bjd.html Enter RA/DE coordinates, then Click "Submit Query" and within the "blink of an eye" you see the BJD (based on TDB time standard) listed in an answer window! Just copy this BJD_TDB to wherever you want it (spreadsheet, e-mail, etc), and be sure to note that this mid-transit time is BJD_TDB, the new "Gold Standard" for all exoplanet investigations. Note, you can copy & paste hundreds of JD_UTC values to the above web site input window, and then copy the same number of BJD_TDB times from the answers window.For a fuller discussion of the many time standards and reference frames, and the reasons for adhering to a new standard of reporting astronomical observations, read the article by Eastman et al (2010): http://arxiv.org/abs/1005.4415Bruce GaryHereford Arizona Observatory

 

 

 

[sumas]

no nie, no bo:

スーパーWASPは全天に渡って、15等級までの太陽系外惑星の通過を検出するプロジェクトである。WASPとはWide Angle Search for Planetsという言葉の略である。

 

スーパーWASPは、2つの機械的な観測から成り立っている。北半球ではカナリア諸島ラ・パルマ島のロク・デ・ロス・ムチャチョス天文台、南半球では南アフリカ共和国の南アフリカ天文台が担当している。それぞれの天文台には、 2k×2kの高品質のCCDイメージセンサを備えた8機のキヤノン200 mm f1.8レンズを設置している。望遠鏡はOptical Mechanics, Inc.で作られたものである[1]。キヤノンのレンズの広い視野により、それぞれの天文台で点当たり500°という広い範囲の観測が可能である。

 

天文台は継続的に観測を行ない、およそ1分間に1枚の画像を撮影する。これは一晩では合計100ギガバイトのデータ量に及ぶ。トランジット法を用いることにより、集められたデータでそれぞれの画像ごとの各恒星の明るさを測定し、恒星の前面を通過する大きな惑星による恒星の明るさのわずかな変化を検出することができる。

 

スーパーWASPは、Instituto de Astrofisica de Canarias、the Isaac Newton Group of Telescopes、キール大学、レスター大学、オープン大学、クイーンズ大学ベルファスト、セント・アンドリューズ大学の8 つの研究機関からなるコンソーシアムによって運営されており、将来の地球型惑星探索のために惑星の進化を解明することが期待されている。

 

sorry za ten głupi żart, ale mógłbyś tak bardziej po tutejszemu pisać?

Edytowane 16 Lipca 2010 przez sumas