Date: September 6, 2009
Title: Eyes Above: The Emotions of a Scientific Discovery
Podcaster: Mario Damasso
Organization: Astronomical Observatory of the Autonomous Region of the Aosta Valley (OAVdA)
Description: We are a group of astronomers working together, searching the sky above our observatory for new worlds, small solar system bodies, and super-massive black holes in galaxies billions of light years far from us. This multi-voice tale will focus in particular on one remarkable episode related to our researches: on 2007, September 7, we discovered an asteroid — now named 2007 RT6 — which was the first ever discovered in our observatory. All this happened while a meeting for amateur astronomers was being hosted in the observatory, providing a unique opportunity to share with them all “the emotions of a scientific discovery.”
Bio: Opened in August 2003, the Astronomical Observatory of the Autonomous Region of the Aosta Valley (OAVdA) is located in the North-West of Italy in the Saint-Barthélemy valley, 1675 m above the sea level. A permanent staff of scientists is involved in research projects related to solar physics, small solar system bodies, active galactic nuclei and extrasolar planets, in tight collaboration with national and international research institutions. The OAVdA is also actively involved in organizing didactical activities for school students and events for the general public. Several education & outreach activities have been planned to promote the International Year of Astronomy 2009.
Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by Clockwork Active Media Systems. Clockwork invents, designs, develops and maintains web applications that market, sell, streamline, automate and communicate. Visit clockwork.net or email inquiries at clockwork.net to get started on your web project.
Transcript:
Mario Damasso (astronomer): Hello to everybody, lovers of the sky and of the beauty of the Universe. These voices are reaching you, all around the world, from the north of Italy in the Alps mountains. We are in the Astronomical Observatory of the Autonomous Region of the Aosta Valley, and me and my colleagues we spend all the time here working and studying the sky.
Tonight is a mid-summer night and the sky is incredibly full of stars. So, as usual, we are beginning our observations. We are inside the dome of our observatory, close to the main telescope that gave us already a lot of satisfactions.
[the background noise is produced by the electrical engine which put the dome roof in movement]
The dome is moving now and the telescope is ready to be pointed in the sky.
In the evening of September 7th of two years ago my colleague, the astronomer Albino Carbognani, was performing the same actions, as usual before starting the observations.
Albino, what is your research field here in the Observatory?
Albino Carbognani (astronomer): I work on asteroids. Asteroids are minor bodies of the Solar System and they are located between the orbits of the planets Mars and Jupiter. My research field can be divided in three main points: NEAs follow-up, NEAs photometry, and statistical analysis of main-belt and Trojan asteroids.
MD: What are NEAs asteroids?
AC: NEAs asteroids are asteroids whose orbits are close to the Earth orbit and so they pose a collision danger for our planet.
MD: Albino, how are asteroids discovered?
AC: Well, this is a good question. Asteroids are discovered by a four steps process. First, you must take a photography — a CCD image — of a region of the sky. Second, you must take another image of the same part of the sky and compare the two images you have taken. For the comparison of the two images you must use the blinking technique that you can perform with a software, an astrometric software, and any body in orbit around the Sun moves within the pair of images. The body appears to float above the background stars. So, it is very easy to discover an asteroid. Then, when a moving body is identified its location is measured using the software, and similar measurement must be repeated the next day. Once you have the astrometric measurements, you must send them to the Minor Planet Center, where a computer program determines if this is really a new asteroid of it is an old asteroid already known. If the object is a new asteroid it receives a provisional catalogue number, consisting of the year of the discovery and an alphanumeric code indicating the half-month of the discovery and the sequence within the half-month. The observer of the first apparition is declared the discoverer and granted the honour of naming the object, subject to the approval of the International Astronomical Union.
MD: Now let’s go back to the night of September 7th of two years ago. You were here, looking for asteroids, and…
AC: …and I took an image of the Aries constellation. This image was compared with another image I took two hours after and I saw a little bright object floating above the background stars. I took astrometric measurements of the position and I repeated the same measure the next day. In the meantime I was reading the Minor Planet Center catalogue for asteroids, and I saw that probably this asteroid was new. So, after two days of observations I sent the astrometric measurements to the Minor Planet Center that confirmed immediately to me that this was a new asteroid of the main belt of the Solar System.
MD: Albino, unfortunately I was not yet here two years ago. So, can you now tell me something about your emotions for this discovery?
AC: It was a very exciting moment for me. It was my first asteroid discovery and I was very excited. I did not sleep for two nights and also for the next week after the discovery!
[again, in background noise from the moving dome roof]
MD: In the meantime the observational session is going on and now the telescope is pointed to the Dolphin constellation. Close to me there is the astronomer Paolo Calcidese, another my colleague in this astronomical observatory. Paolo is involved in a totally different project than Albino.
What about you, Paolo? Which part of the Universe you are exploring with the same telescope?
Paolo Calcidese (astronomer): I am interested in celestial objects that are located billions of light years from the Earth. They are named AGN, Active Galactic Nuclei. According the stronger theoretical model, in the core of this galaxies there is a supermassive black hole. The mass of this black hole is estimated to be several hundreds of millions solar masses. My work is a multi-frequency study of these objects.
The Observatory is a member of an international consortium, the WEBT. In this observatory I take optical images of AGN, but the WEBT uses also data coming from the Medicina radio telescope, in Italy, and from satellites for X and gamma rays.
MD: As for Albino, even for you there is one night that is special. It was the 22nd of July of two years ago and you were observing an object in the constellation of the Lizard, when something strange happened…What exactly?
PC: Yes, that night I was observing that active nucleus named BL LAC 2200+420 and I was a witness of an evident outburst of light. I was observing this object from 58 nights and that one I was the only one in the world to record this important event.
It was a really important moment for me because that was the first time that I saw an AGN “in action.” and this kind of phenomena is very rare to be observed. To monitor the evolution of the outburst I did not sleep for two nights!
ND: And finally, while the telescope is still looking back in space and time, it is my turn to introduce myself. My name is Mario Damasso and I am working here as an extrasolar planet hunter. My researches for new worlds are just started here, but me too I have something to share with you.
The method I apply to search for planets around other stars consists in looking for planetary shadows. If a star hosts a planet orbiting around, it is possible to find it if it passes in front of its parent star, producing a sort of stellar eclipse. An extrasolar planet will leave its sign producing a dimming in the light of the star that we receive and measure during each night.
It seems that few nights ago I found such sign in a small star not far from the Milky Way. But it is too early to say “Yes! I got a new planet!” For the moment I just wanted to share with you all the emotions I had looking to my data for the first time some nights ago. Now…now we just have to keep our eyes above, night after night, restless…and a new discovery will be for sure the best award for us!
End of podcast:
365 Days of Astronomy
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The 365 Days of Astronomy Podcast is produced by the New Media Working Group of the International Year of Astronomy 2009. Audio post-production by Preston Gibson. Bandwidth donated by libsyn.com and wizzard media. Web design by Clockwork Active Media Systems. You may reproduce and distribute this audio for non-commercial purposes. Please consider supporting the podcast with a few dollars (or Euros!). Visit us on the web at 365DaysOfAstronomy.org or email us at info@365DaysOfAstronomy.org. Until tomorrow…goodbye.