Scientific Activities   

Since its inauguration on March 2011, The Weizmann Institute of Science’s observatory has been involved in several scientific research projects with significant results. This is remarkable, since the observatory, residing in an urban area, was not designed primarily for scientific work.   

  • μFUN

The Weizmann Institute of Science Martin S. Kraar Observatory participates on a regular basis in the μFUN project, the Microlensing Follow-Up Network (see here), a network of a dozen observatories, mainly in the southern hemisphere, which collaborate in an effort to detect exoplanets (planets revolving around stars other than our Sun) around stars residing in the bulge of our Milky Way galaxy, using a technique called gravitational microlensing.   

Starting in the beginning of spring and continuing till the end of autumn, the uFun central node at OSU circulates messages to participating observatories about potential events. Targets which are bright enough are imaged for a full night or more.   

A microlensing event usually requires the combined efforts of several observatories to record its full span. On July 4th, 2011, we were in the right location and at the right time to record such an event, the peak of which took place during our ‘shift’. Thus we were able to register uniquely the telltale signatures of a planet when its host star went through a microlensing event.  

The resulting paper, titled “MOA-2011-BLG-293Lb: A Test of Pure Survey Microlensing Planet Detections”, accounting this discovery and providing details about the participation of the Weizmann Institute of Science Martin S. Kraar Observatory in the global observing campaign, which culminated in the discovery of an exoplanet, can be found here and here.  

Following is a triplet of small sections of the  images taken at different times during the event, with the discovery clearly marked. The increase in the luminosity of the star marked is due to the gravitational amplification of its light by a gravitational lens, composed of a star+planet system. (Clicking on the image will open a larger frame):  

 

Below is a light curve of the microlensing event of MOA-2011-BLG-293. The left-hand panel shows a broad view of the light curve, while the right-hand panel highlights the peak of the event where the planetary perturbation occurs. Data from different observatories are represented by different colors, where the WIS MKO contribution to this discovery is in yellow, indicating observation at the exact time of planetary transition. The black curve is the best-fit model with a close topology (s < 1). The times are given in HJD’ = HJD−2450000: 

     

 

  •  Occultation of a star by KBO 2003 AZ84

KBOs (Kuiper Belt Objects) are large bodies located at the outer reaches of the solar system, also known as TNOs (Trans-Neptunian Objects). Due to their large distance from the Sun and their relatively low albedo, their intrinsic brightness is such that not much information about these objects can be obtained telescopically. Finding the size of these remote objects is therefore extremely difficult.

One of the methods employed for obtaining this purpose is an occultation. During an occultation, a solar system object ‘hides’ the light of a faraway star for a certain duration, usually in the order of seconds of time. From this duration, while knowing the object’s precise distance from the Sun during the occultation, one can measure the occulting object’s unknown size.    

A Kuiper Belt Object (KBO)’s occultation is a rare event and the prediction of the occultation path often shifts quite significantly several days before the event itself. The night of the occultation, February 3rd 2012, was almost lost due to bad weather, which cleared just in time for preparing the observatory for this demanding observation.    

As it turns out, from the 17 observatories which participated in the campaign to observe KBO 2003 AZ84’s occultation, only two were able to contributed data – one in India, which had scant information and the WIS MKO, which saw the full duration of the occultation. From this data is was deduced that the size of the KBO is between 575 km (lower limit) and 1125 km (upper limit). A lightcurve of the data analysis of the occultation can be seen here:    

  

  

  • Observatory Code

One of the first achievements of the observatory was the assignment of an official Observatory Code by the IAU/MPC (International Astronomical Union / Minor Planet Center).

The IAU/MPC enforces a strict protocol of observation of several asteroids, each at a different magnitude, for several consecutive nights to justify the approval of an Observatory Code. The Weizmann Institute of Science Martin S. Kraar Obervatory was assigned Observatory Code C78. 

  

  • Supernova in M51

On May 27, 2011 a relatively bright type IIb supernova (SN) occured in a nearby galaxy M51 (the Whirlpool Galaxy, ~30 million light years distant). The Weizmann Institute of Science Martin S. Kraar Obervatory was one of the first observatories in the world to observe this SN soon after its discovery, contributing data relating to the early phases of this event.    

Following is the image of M51 obtained one day after the supernova’s eruption. It was taken in monochrome through several different filters and combined into a single, color image. The supernova is circled:    

     

  

  • Experimental Equipment Benchmark

The WIS MKO observatory is also used for testing new instrumentation to evaluate its utilization in scientific research.