06 April 2006

HabStars and Travel Plans

From: http://www.spaceref.com/news/viewpr.nl.html?pid=19462
ANU astronomers have discovered a nearby solar twin which may shed light on the search for planets that are similar to Earth and that may even support life.
HD98618 is only the second star found so far that is almost identical to the Sun in age, size, temperature and chemistry, according to the researchers Dr Jorge Meléndez, Ms Katie Dodds-Eden and Mr José Robles, from the Research School of Astronomy and Astrophysics.
"This solar twin doesn't only have the same mass as the Sun, it was also formed with the same 'chemical recipe'. So this star was equipped in the same way as the Sun to form Earth-like planets," Mr Robles said.
"Hopefully, as new planet finding techniques are developed and refined, astronomers will find whether HD98618 hosts terrestrial planets, which may even contain life."
HD98618 lies a mere 126 light-years away in the northern constellation of Ursa Major (the 'Big Dipper'). It is bright enough to see in binoculars, but only in the Northern Hemisphere.
The researchers believe that HD98618 is about four billion years-old, about 10 per cent younger than our own Sun. Its chemical properties are almost identical to the Sun and to the other closest Sun twin, a star known as 18 Scorpii, which was discovered a decade ago.
"It means that hypothetical terrestrial planets around this solar twin may have had enough time to develop some kind of complex life, assuming the time-scale for complex life formation is similar to Earth's," Dr Meléndez said.


Hopefully humanity will achieve the ability to travel beyond our system. When we do, it will be useful to have a plan for how to survey and expand. Even if we are "Transhuman" in this timeframe, we will likely still want to watch systems similar to our own (in the same way we watch avian flu to ensure it does not become virulent), and it is unlikely that the tyranny of distance will be completely eradicated even if we achieve radical life extension. Resources are likely to always constrain our ambitions, and we will have to choose what gets priority.

Therefore we should at least start to think about our priority for exploration. Good initial candidates might be picked from the SETI projects top most habitable stars, which were lately articulated by Margaret Turnbull ( http://www.space.com/scienceastronomy/060221_habstars.html ). We may also want to give thought to the structure of the search, not unlike previous exploration missions were fleets travel together for a time before splitting up, to circuits of travel, and to starts that lie in a plane and can use common navigational references.

Some of these considerations are expressed in the following Astronomy Magazine article, by Margorie Fish. While this is a favorite among the true believers in the UFO community, it is still a very useful group of well thought-out criteria for local exploration. The article is reprinted at the below links:

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