Show Notes: April 9th, 2013 UTC
Hosts: Paul, Jesse, Ryan (and Lianne)
Title: Yuri’s Night and Lianne’s Fight
Lianne fought valiantly with her internet connection in order to join us on-air for the show, but alas, the internet won. While we did miss her, we were able to talk about oxygen and carbon found in the atmosphere of an extrasolar planet, as well as chat about the rate of type 1a supernovae in the early universe. This April 12th, 2013 will be the 52 anniversary of the benchmark flight of Yuri Gagarin, the first human to ever leave their earthly bounds and venture into space. This is now celebrated worldwide as ‘Yuri’s Night.’ Look for an astronomy/space club near you that’s celebrating and enjoy the festivities. As always, thanks for listening. See below for the show notes and podcast.
This week in space/astronomy history:
1. April 9, 1959 – NASA selects the Original Seven: Alan Shepard, Gus Grissom, John Glenn, Scott Carpenter, Wally Schirra, Gordon Cooper, and Deke Slayton
2. April 8, 1993 & 2002 – Ellen Ochoa – Two flights to space on the SAME day
3. April 12, 1961 – Yuri Gagarin is the first human in space. Yuri’s Night! celebration in Toronto http://yurisnight.ca/
1. YorkUniverse.com Update: Lianne (follow on twitter) is posting an OPV image of the week! The Online Public Viewing, as well as other outreach efforts of the York Observatory, result in many amazing images. Each week Lianne is posting the best of the best!
Also feel free to use our website to comment on our show, ask questions, or suggest content. Look forward to hearing from you.
2. ‘Curiosity Corner,’ on location with Ryan Marciniak (follow on twitter)! New article: http://www.bbc.co.uk/news/science-environment-22063337
3. International Dark Sky Week – http://www.darksky.org/resources/109-international-dark-sky-week
4. Crescent Moon – Pleiades conjunction at the end of the week
Major Topics Discussed:
1. Water found in the atmosphere of extrasolar planet (lead by Jesse)
Researchers have used the Keck Observatory (@KeckObservatory) to make the most detailed measurement of the properties of an exosolar planet’s atmosphere. The observatory’s technology, mixed with the state of the art techniques of the researchers, and the planetary body itself have helped make this measurement happen.
The planet observed was HR8799c, a giant Jupiter.
This experiment has made the sharpest spectrum ever obtained of an extrasolar planet.
Using OSIRIS (the OH suppressing Infrared Imaging Spectrograph), the astronomers have detected a cloudy atmosphere with water vapour and carbon monoxide. This allows a direct comparison between the amount of carbon and the amount of oxygen in the atmosphere
Two Scenarios of Planet Formation:
1. Core Accretion: planets form slowly, beginning as a small protoplanet and then slowly accreting more material (and gas) onto them.
2. Gravitational Instability: planets form instantly as part of the gravitational collapse into a disk of the entire solar system.
This planet, HR8799c, has a high ratio of carbon to oxygen. Meaning there is less oxygen in the planet than expected. How did the astronomers know what to expect? If planets form quickly, i.e., through gravitational instability, then you would expect their composition to be similar to the parent star, as they would have been collapsing at the same time. Since there is less oxygen in the giant-Jupiter, the authors expect this means the planet took longer to form, favouring the ‘core accretion’ scenario.
But where did all the oxygen go? As the disk of debris around a proto-planetary disk cools down, this allows ice to form, depleting the gas of oxygen. Therefore, the gas accreted by the proto planetary core no longer has a large amount of oxygen in it.
The astronomers first imaged the planet (yes….imaged) using the Near Infrared Imager on Keck-II. By determining that the ratios of various molecules and elements, like water and carbon, they can distinguish between the two planetary formation models.
2. Furthest known Supernova type 1a
Astronomers have discovered the new record for the most distant supernova. The astronomers used data from the Hubble Space Telescope, in a campaign called CANDELS+CLASH Supernova Project. The new record holder has redshift of 1.9, which puts its cosmological distance at roughly 10.2 billion light years.
This is a type 1a supernova, the type of explosion resulting from a white dwarf that has reached its mass limit by eating material from somewhere else. The mass limit is 1.4 solar masses, and is the point at which neuclei degeneracy can no longer support the white dwarf. If a white dwarf exceeds 1.4 solar masses, it begins a chain reaction of collapse and immediate fusion, tearing apart the object in a supernova. There are two ways we know of that could provide mass to a white dwarf: 1) by stealing mass from a red giant’s atmosphere, 2) by merging with another white dwarf.
By observing type 1a supernovae at further and further distances, we may be able to distinguish between which scenario is the dominant one. This is possible because scenario 1, the mass transfer model, only requires one white dwarf, while scenario 2 requires two white dwarfs. The latter therefore requires more time to have evolved so more white dwarfs can be formed, enough to sufficiently account for the number of type 1a supernovae seen. You would expect to see more type 1a further back in time if scenario 1 is true than if scenario 2 is true.
The reasearchers who are part of this project have indicated the expected to see more supernovae type 1a at these high distances, which may suggest that most type 1a’s are a result of two white dwarfs merging. Of course more work is required, but this evidence is telling.
play with cosmo calc!
Thanks for listening!
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