NASA's Search for Planet Vulcan -Beyond the Physics of Star Trek

"SIM is going to provide an answer to the question ... are there other Earths?"
- Dr. Geoff Marcy, University of California, Berkeley

Like a scene from a Star Trek sequel, astronomers at NASA's Jet Propulsion Laboratory have concluded that the SIM PlanetQuest mission would be able to detect an Earth-like planet around 40 Eridani, a star familiar to "Star Trek" fans as the location of Spock's home planet, Vulcan.

SIM PlanetQuest, scheduled for launch within the next decade, will be the world's most powerful planet-hunting space telescope. Using two separated mirrors and combining their light with a technique known as interferometry, space telescope will able to detect rocky planets as small as Earth around nearby stars -the kind of planets that scientists believe have the most potential to support life.

In a survey of the best 120 candidate stars for hosting such planets in the 'habitable zone,' SIM would have the sensitivity to find planets smaller than Earth around six stars, planets smaller than two Earth masses around 24 stars, and planets smaller than three Earth masses around every star in the survey group.  The habitable zone is the region around a system's star where we can expect to find liquid water at the surface. If the planet is too hot, the water becomes vapor and is lost from the atmosphere. If the planet is too cold, the water freezes. Either of these conditions would make a planet very inhospitable for life.

Back to the search for the Planet Vulcan: 40 Eridani, a triple-star system 16 light-years from Earth, includes a red-orange K dwarf star slightly smaller and cooler than our sun, which Vulcan is thought to orbit

Astronomer Dr. Angelle Tanner at Caltech had two questions about the upcoming search for Vulcan: Can a planet form around 40 Eridani A? Can SIM detect such a planet?  Answering Tanner, Dr. Sean Raymond of the University of Colorado, Boulder believes that "Since the three members of the triple star system are so far away from each other, I see no reason why an Earth-mass planet would not be able to form around the primary star, 40 Eridani A."

If Vulcan life were to exist on the planet, the orbit of the planet would have to lie in a sweet spot around the star where liquid water could be present on its surface. Water is an essential ingredient for any organism to live long and prosper. For 40 Eridani A, this spot, or "habitable zone," is 0.6 astronomical units from the star - six-month "year."

The planet-detection technology of the SIM PlanetQuest instrument will be so accurate, it could measure the thickness of a nickel at a distance from Earth to the moon. Using a set of mathematical models based on Newton's Laws, Tanner was able to conclude that SIM would be able to definitively determine whether there is an Earth-mass planet orbiting in the habitable zone around 40 Eridani A.

When asked what life would be like on Vulcan, Tanner speculated that the inhabitants might be pale. "A K dwarf star emits its light at wavelengths which are a bit redder compared to those from the Sun, so I wonder whether it's harder to get a tan there," she said.

In addition to searching for earthlike planets, SIM PlanetQuest will map our galaxy in attempting to answer how big is the Milky Way galaxy? How fast does it rotate? Where, in its vast expanses, is our sun located?

Based on radio astronomical investigations of the distribution of hydrogen clouds, we do know that the Milky Way is a rotating disc-shaped gathering of stars, gas and dust about 100,000 light-years across and 1,000 light-years thick. Our sun is located along one of the Milky Way's spiral arms, but its exact distance from the center of the galaxy is unknown.

SIM PlanetQuest will use optical interferometry to measure the distances between stars throughout the galaxy with unprecedented accuracy. Interferometry is the process of combining light from two or more telescopes as if they were pieces of a single, gigantic telescope mirror.

Posted by Casey Kazan.

NASA PlanetQuest Link

Cruising the Goldilocks Zone -Search for Super Earths

Beyond the Physics of Star Trek
http://www.dailygalaxy.com/my_weblog/2007/07/neutron-star-ch.html

History of Planet Vulcan
http://www.typepad.com/t/app/weblog/post?__mode=edit_entry&id=34272038&blog_id=604253

Comments

[ET]

I think Tanner is exaggerating.

The UV light reaching the surface of a planet orbiting 40 Eridani would not be all that much lower, perhaps half that on Earth.

So, though the inhabitants would be slightly paler, on average, it is unlikely they would all be white. They could also come in yellow or brown, especially near the equator or in the vast desert regions of Vulcan. Of course, that is assuming, rather madly, Vulcans even use melanin or they even exist.

[ET2]

According to the paper published in 2006, titled "Spectral Signatures of Photosynthesis. II. Coevolution with Other Stars and the Atmosphere on Extrasolar Worlds"

The surface of an Earth similar planet orbiting 40 Eridani, in the habitable zone, would receive 67.5 percent the amount of UV A and, more importantly, 83.3 percent the amount of UV B, the light used to make Vitamin D which is the main determinant in skin shade evolution.

Therefore, the hypothetical Vulcan would not necessarily be any paler and could actually have exactly the same range of skins tones as humans, from white to black.