Oct 9, 2026 · 34 min · 9 segments
What can a visitor from another star system teach us about our own cosmic neighborhood? Join host Dr. Franck Marchis and guest Dr. Cecilia Tubiana (INAF) for a conversation about interstellar comet…
Franck MarchisHostOne, one thing that should be kept in mind is that the observation secured, uh, in November, between the 5th and the 25th of November, but the data took three months to come to ground.
Uh, how do we get a production rate, water production rate? Well, uh, this is, um, done through spectra.
And, um, the, the lines from this, um, from this spectra, uh, are a indication of which are the, the molecules which are visible in the, in the coma of the... or in the coma or in the nucleus of the, of the object.
In this case it's the coma, which is this, uh, dust and gas which is all around the nucleus because the nucleus is, uh, so the comet are done of, uh, dust and ice.
When the, the comet comes in the vicinity of the sun, uh, the, the ice sublimates and creates this sort of cloud, uh, around the nucleus r- and hiding the nucleus from, from the view.
And so what we actually see, uh, when the comet is, uh, close to the sun is mainly the, the coma and the-
And, uh, Majis observed, uh, during the, um, the, the beginning of the observing campaign, uh, observed three times, uh, this, um, this object.
And, uh, in their spectra they could, uh, see the line which comes from the, um, from the water.
And, uh, and from, from the, from the intensity of the line you determine which is the abundance of, uh, of this species.
One, one thing that should be kept in mind is that the observation secured, uh, in November, between the 5th and the 25th of November, but the data took three months to come to ground.
Uh, how do we get a production rate, water production rate? Well, uh, this is, um, done through spectra.
And, um, the, the lines from this, um, from this spectra, uh, are a indication of which are the, the molecules which are visible in the, in the coma of the... or in the coma or in the nucleus of the, of the object.
In this case it's the coma, which is this, uh, dust and gas which is all around the nucleus because the nucleus is, uh, so the comet are done of, uh, dust and ice.
When the, the comet comes in the vicinity of the sun, uh, the, the ice sublimates and creates this sort of cloud, uh, around the nucleus r- and hiding the nucleus from, from the view.
And so what we actually see, uh, when the comet is, uh, close to the sun is mainly the, the coma and the-
And, uh, Majis observed, uh, during the, um, the, the beginning of the observing campaign, uh, observed three times, uh, this, um, this object.
And, uh, in their spectra they could, uh, see the line which comes from the, um, from the water.
And, uh, and from, from the, from the intensity of the line you determine which is the abundance of, uh, of this species.
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