Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NCAR Scientist to View Venus’s Atmosphere during Transit, Search for Water Vapor on Distant Planet

04.06.2004


The newest generation of spectroscopes will give scientists their best look yet at gases and winds in Venus’s upper atmosphere during the planet’s first transit of the Sun in 122 years. (Courtesy NASA and the NSSDC)


On June 8 Earth-based solar telescopes will follow a tiny black orb as it appears to travel effortlessly across a wrinkled, brilliant sea. Timothy Brown, a scientist at the National Center for Atmospheric Research (NCAR), will not sit idly by as Venus traverses the Sun for the first time in 122 years at an angle visible from Earth. Peering through a specialized solar telescope in the Canary Islands, Brown will study the chemical composition and winds of Venus’s upper atmosphere, a region poorly observed until now. NCAR’s primary sponsor, the National Science Foundation (NSF), is funding the research.

An extrasolar planet expert at NCAR’s High Altitude Observatory (HAO), Brown has been applying a technique known as spectroscopy to piece together atmospheric data on a planet orbiting star HD209248, located 150 light years from Earth. He found sodium in the planet’s atmosphere in 2001 and is now searching for water and carbon monoxide. HAO director Michael Knölker, who specializes in precision solar spectroscopy, is a coinvestigator on the Venus project.

During next week’s transit, Brown will apply the same technique to examine regions of the solar spectrum that are strongly absorbed as they pass through Venus’s atmosphere between 65 and 85 kilometers (40 and 53 miles) altitude—a region above the planet’s thick cloud layer.



Each wavelength absorbed will indicate the presence of a specific gas and its height in the atmosphere. Brown will also be able to construct wind patterns based on the gases’ Doppler shifts, that is, their motion toward or away from Earth.

"This is Venus’s first transit in front of the Sun since quantitative astronomical spectroscopy was invented," explains Brown, "so it’s our first chance to use the technology to observe close up the transit of a planet with an atmosphere." Venus, Mars, and Earth constantly orbit the sun. Only when the orbital planes and positions align in a particular way is a transit across the solar disk by Mars or Venus visible from Earth. Mercury’s transits are visible every few years—its last trip was in November 1999—but whatever atmosphere it may have is far too thin to be observed.

Brown will examine the Venusian atmosphere using a vacuum tower telescope located on Tenerife in the Canary Islands, a Spanish province near the northwest coast of Africa. The 70-centimeter solar telescope and its infrared spectrograph are operated by the Kiepenheuer Institute in Freiburg, Germany. The spectrograph works well for the occasion since the planet’s atmosphere is composed almost entirely of carbon dioxide, a gas that absorbs near-infrared radiation.

Scientists have learned much about Venus’s atmosphere since its discovery two hundred years ago. In recent times, probes from orbiting spacecraft have measured its chemical composition and temperature at various heights. These data have enabled scientists to construct computer models of the planet’s atmosphere. But the region that Brown will be observing has escaped close scrutiny until now.

"I hope to make a substantial addition to knowledge of an atmospheric region not well observed in the past," says Brown. "But also the experiment will be a source of great inspiration and motivation for investigating the atmospheres of extrasolar planets."

Applying spectroscopy to a distant planet too tiny to see directly is a challenge far greater than observing a neighboring planet in our own solar system.

"Observations of extrasolar planets as precise and compelling as those of Venus will not happen in my lifetime or that of my children," says Brown. "What we can see on Venus today previews what will be seen on far distant planets long after I’m gone. You could say it’s cheating on time."

Brown believes his own observations of a planet circling the star HD209248 will reveal whether there are significant clouds, dust, or particles in that planet’s upper atmosphere, how big the particles are, and what the dust is made of. His observations using the Hubble Space Telescope in 2001 revealed the presence of sodium, and he thinks carbon monoxide may show up soon. Later this year he will continue his search for water vapor around the same planet, again using the Hubble.

The planet is so close to its star that its annual orbit lasts only 3.5 days, and it is perpetually blasted by ultraviolet radiation and thousand-degree heat.

"Whatever can withstand those temperatures is what’s there," says Brown. "In other words, no little green men."

Knölker was a scientist with the Kiepenheuer Institute for many years before coming to NCAR. He has been using the telescope on Tenerife for solar spectroscopy, and he was part of a team that observed the impact of the Shoemaker-Levy comet on Jupiter in 1994.

Brown’s other collaborators in the Venus observations are Wolfgang Schmidt and Helmhold Schleicher, both of the Kiepenheuer Institute, and Roi Alonso Sobrino, a graduate student at the Astrophysics Institute of the Canary Islands. NASA and NSF fund Brown’s extrasolar planet research.

Anatta | UCAR
Further information:
http://www.ucar.edu/news/releases/2004/venus.shtml

More articles from Physics and Astronomy:

nachricht SF State astronomer searches for signs of life on Wolf 1061 exoplanet
20.01.2017 | San Francisco State University

nachricht Molecule flash mob
19.01.2017 | Technische Universität Wien

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>