ESO: ALMA observes stellar cocoon in nearby galaxy with odd chemistry

A new report from the European Southern Observatory (ESO):

ALMA Catches Stellar Cocoon with Curious Chemistry

A hot and dense mass of complex molecules, cocooning a newborn star, has been discovered by a Japanese team of astronomers using [the Atacama Large Millimeter/submillimeter Array (ALMA)]. This unique hot molecular core is the first of its kind to have been detected outside the Milky Way galaxy. It has a very different molecular composition from similar objects in our own galaxy — a tantalising hint that the chemistry taking place across the Universe could be much more diverse than expected.

This artist’s impression shows the molecules found in a hot molecular core in the Large Magellanic Cloud using ALMA. This core is the first such object to be found outside the Milky Way, and it has significantly different chemical makeup to those found in our own galaxy. The figure is a derivative work based on material from the following sources: ESO/M. Kornmesser; NASA, ESA, and S. Beckwith (STScI) and the HUDF Team; NASA/ESA and the Hubble Heritage Team (AURA/STScI)/HEI.
This artist’s impression shows the molecules found in a hot molecular core in the Large Magellanic Cloud using ALMA. This core is the first such object to be found outside the Milky Way, and it has significantly different chemical makeup to those found in our own galaxy. The figure is a derivative work based on material from the following sources: ESO/M. Kornmesser; NASA, ESA, and S. Beckwith (STScI) and the HUDF Team; NASA/ESA and the Hubble Heritage Team (AURA/STScI)/HEI. [Larger images]
A team of Japanese researchers have used the power of the Atacama Large Millimeter/submillimeter Array (ALMA) to observe a massive star known as ST11 [1] in our neighbouring dwarf galaxy, the Large Magellanic Cloud (LMC). Emission from a number of molecular gases was detected. These indicated that the team had discovered a concentrated region of comparatively hot and dense molecular gas around the newly ignited star ST11. This was evidence that they had found something never before seen outside of the Milky Way — a hot molecular core [2].

Takashi Shimonishi, an astronomer at Tohoku University, Japan, and the paper’s lead author enthused:

“This is the first detection of an extragalactic hot molecular core, and it demonstrates the great capability of new generation telescopes to study astrochemical phenomena beyond the Milky Way.”

The ALMA observations revealed that this newly discovered core in the LMC has a very different composition to similar objects found in the Milky Way. The most prominent chemical signatures in the LMC core include familiar molecules such as sulfur dioxide, nitric oxide, and formaldehyde — alongside the ubiquitous dust. But several organic compounds, including methanol (the simplest alcohol molecule), had remarkably low abundance in the newly detected hot molecular core. In contrast, cores in the Milky Way have been observed to contain a wide assortment of complex organic molecules, including methanol and ethanol.

This figure shows observations of the first hot core to be found outside the Milky Way with ALMA and a view of the region of sky in infrared light. Left: Distributions of molecular line emission from a hot molecular core in the Large Magellanic Cloud observed with ALMA. Emissions from dust, sulfur dioxide (SO2), nitric oxide (NO), and formaldehyde (H2CO) are shown as examples. Right: An infrared image of the surrounding star-forming region (based on data from the NASA/Spitzer Space Telescope).
This figure shows observations of the first hot core to be found outside the Milky Way with ALMA and a view of the region of sky in infrared light. Left: Distributions of molecular line emission from a hot molecular core in the Large Magellanic Cloud observed with ALMA. Emissions from dust, sulfur dioxide (SO2), nitric oxide (NO), and formaldehyde (H2CO) are shown as examples. Right: An infrared image of the surrounding star-forming region (based on data from the NASA/Spitzer Space Telescope). [Larger images]
Takashi Shimonishi explains:

“The observations suggest that the molecular compositions of materials that form stars and planets are much more diverse than we expected.”

The LMC has a low abundance of elements other than hydrogen or helium [3]. The research team suggests that this very different galactic environment has affected the molecule-forming processes taking place surrounding the newborn star ST11. This could account for the observed differences in chemical compositions.

It is not yet clear if the large, complex molecules detected in the Milky Way exist in hot molecular cores in other galaxies. Complex organic molecules are of very special interest because some are connected to prebiotic molecules formed in space. This newly discovered object in one of our nearest galactic neighbours is an excellent target to help astronomers address this issue. It also raises another question: how could the chemical diversity of galaxies affect the development of extragalactic life?

Notes

[1] ST11’s full name is 2MASS J05264658-6848469. This catchily-named young massive star is defined as a Young Stellar Object. Although it currently appears to be a single star, it is possible that it will prove to be a tight cluster of stars, or possibly a multiple star system. It was the target of the science team’s observations and their results led them to realise that ST11 is enveloped by a hot molecular core.

[2] Hot molecular cores must be: (relatively) small, with a diameter of less than 0.3 light-years; have a density over a thousand billion (1012) molecules per cubic metre (far lower than the Earth’s atmosphere, but high for an interstellar environment); warm in temperature, at over –173 degrees Celsius. This makes them at least 80 degrees Celsius warmer than a standard molecular cloud, despite being of similar density. These hot cores form early on in the evolution of massive stars and they play a key role in the formation of complex chemicals in space.

[3] The nuclear fusion reactions that take place when a star has stopped fusing hydrogen to helium generate heavier elements. These heavier elements get blasted into space when massive dying stars explode as supernovae. Therefore, as our Universe has aged, the abundance of heavier elements has increased. Thanks to its low abundance of heavier elements, the LMC provides insight into the chemical processes that were taking place in the earlier Universe.

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Video: SpaceX unveils the Interplanetary Transport System

Coming up at 2:30 pm ET today, Elon Musk will describe the design of the “SpaceX Interplanetary Transport System” that will be used to send people to Mars and elsewhere. Here is a video animation of the system:

You can watch his talk online here:

Update: Here are the slides that Elon showed during hits talk: Mars Presentation (pdf)

Hubble space telescope images show possible water plumes erupting from Europa

A team using the Hubble telescope spots possible water plumes erupting on Jupiter’s moon Europa. Here is the official NASA press release:

NASA’s Hubble Spots Possible Water Plumes Erupting on Europa

Astronomers using NASA’s Hubble Space Telescope have imaged what may be water vapor plumes erupting off the surface of Jupiter’s moon Europa. This finding bolsters other Hubble observations suggesting the icy moon erupts with high altitude water vapor plumes.

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This composite image shows suspected plumes of water vapor erupting at the 7 o’clock position off the limb of Jupiter’s moon Europa. The plumes, photographed by NASA’s Hubble’s Space Telescope Imaging Spectrograph, were seen in silhouette as the moon passed in front of Jupiter. Hubble’s ultraviolet sensitivity allowed for the features, rising over 100 miles above Europa’s icy surface, to be discerned. The water is believed to come from a subsurface ocean on Europa. The Hubble data were taken on January 26, 2014. The image of Europa, superimposed on the Hubble data, is assembled from data from the Galileo and Voyager missions. [Larger images]
The observation increases the possibility that missions to Europa may be able to sample Europa’s ocean without having to drill through miles of ice.

“Europa’s ocean is considered to be one of the most promising places that could potentially harbor life in the solar system,” said Geoff Yoder, acting associate administrator for NASA’s Science Mission Directorate in Washington. “These plumes, if they do indeed exist, may provide another way to sample Europa’s subsurface.”

The plumes are estimated to rise about 125 miles (200 kilometers) before, presumably, raining material back down onto Europa’s surface. Europa has a huge global ocean containing twice as much water as Earth’s oceans, but it is protected by a layer of extremely cold and hard ice of unknown thickness. The plumes provide a tantalizing opportunity to gather samples originating from under the surface without having to land or drill through the ice.

 

The team, led by William Sparks of the Space Telescope Science Institute (STScI) in Baltimore observed these finger-like projections while viewing Europa’s limb as the moon passed in front of Jupiter.

The original goal of the team’s observing proposal was to determine whether Europa has a thin, extended atmosphere, or exosphere. Using the same observing method that detects atmospheres around planets orbiting other stars, the team realized if there was water vapor venting from Europa’s surface, this observation would be an excellent way to see it.

“The atmosphere of an extrasolar planet blocks some of the starlight that is behind it,” Sparks explained. “If there is a thin atmosphere around Europa, it has the potential to block some of the light of Jupiter, and we could see it as a silhouette. And so we were looking for absorption features around the limb of Europa as it transited the smooth face of Jupiter.”

In 10 separate occurrences spanning 15 months, the team observed Europa passing in front of Jupiter. They saw what could be plumes erupting on three of these occasions.

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This diagram shows how the plumes on Europa are seen in silhouette as the moon moves across the face of Jupiter. Europa makes a complete orbit of Jupiter in just 3.5 Earth days. [ Larger images]
This work provides supporting evidence for water plumes on Europa. In 2012, a team led by Lorenz Roth of the Southwest Research Institute in San Antonio, detected evidence of water vapor erupting from the frigid south polar region of Europa and reaching more than 100 miles (160 kilometers) into space. Although both teams used Hubble’s Space Telescope Imaging Spectrograph instrument, each used a totally independent method to arrive at the same conclusion.

“When we calculate in a completely different way the amount of material that would be needed to create these absorption features, it’s pretty similar to what Roth and his team found,” Sparks said. “The estimates for the mass are similar, the estimates for the height of the plumes are similar. The latitude of two of the plume candidates we see corresponds to their earlier work.”

But as of yet, the two teams have not simultaneously detected the plumes using their independent techniques. Observations thus far have suggested the plumes could be highly variable, meaning that they may sporadically erupt for some time and then die down. For example, observations by Roth’s team within a week of one of the detections by Sparks’ team failed to detect any plumes.

If confirmed, Europa would be the second moon in the solar system known to have water vapor plumes. In 2005, NASA’s Cassini orbiter detected jets of water vapor and dust spewing off the surface of Saturn’s moon Enceladus.

Scientists may use the infrared vision of NASA’s James Webb Space Telescope, which is scheduled to launch in 2018, to confirm venting or plume activity on Europa. NASA also is formulating a mission to Europa with a payload that could confirm the presence of plumes and study them from close range during multiple flybys.

“Hubble’s unique capabilities enabled it to capture these plumes, once again demonstrating Hubble’s ability to make observations it was never designed to make,” said Paul Hertz, director of the Astrophysics Division at NASA Headquarters in Washington. “This observation opens up a world of possibilities, and we look forward to future missions — such as the James Webb Space Telescope — to follow up on this exciting discovery.”

The work by Sparks and his colleagues will be published in the Sept. 29 issue of the Astrophysical Journal.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (the European Space Agency.) NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. STScI, which is operated for NASA by the Association of Universities for Research in Astronomy in Washington, conducts Hubble science operations.

For images and more information about Europa and Hubble, visit:

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The Space Show this week – Sept.26.2016

The guests and topics of discussion on The Space Show this week:

1. Monday, Sept. 26, 2016: 2-3:30 PM PDT (5-6:30 PM EDT, 4-5:30 PM CDT): Michael Listner returns as our guest on space legal issues and more.

2. Tuesday, Sept. 27, 2016: 7-8:30 PM PDT, 10-11:30 PM EDT, 9-10:30 PM CDT; We welcome back Bob Zimmerman for space news updates.

3. Friday, Sept. 30, 2016: 9:30-11AM PDT; (12:30-2 PM EDT; 11:30 AM – 1 PM CDT) We welcome Casey Dreier from The Planetary Society to discuss Europa.

4. Sunday, Oct. 2, 2016: 12-1:30 PM PDT (3-4:30 PM EDT, 2-3:30 PM CDT): OPEN LINES. All space and STEM topics welcome as are first time callers.

See also:
* The Space Show on Vimeo – webinar videos
* The Space Show’s Blog – summaries of interviews.
* The Space Show Classroom Blog – tutorial programs

The Space Show is a project of the One Giant Leap Foundation.

The Space Show - Moon Rise