Sandoval Signpost

 

An independent monthly newspaper serving the community since 1988
  Night Sky
 

Enjoy the starry night skies
Be a considerate neighbor. Reduce nighttime glare.
Shield your outside lights downward.
Let the stars light up the night.

December 2015 night sky

—Charlie Christmann

KIC 8462852—silence:

Last we left the strange star named KIC 8462852, the SETI Institute was planning on surveying the star to see if they could detect any intelligent radio signals. This is a strange star found in the Kepler telescope data where the light we see dims about twenty percent irregularly. Stars with orbiting planets, even super Jupiter-sized ones, only dim a star by about one percent. The weird dimming led some to suggest the presence of a large artificial structure orbiting the star implying the possibility of an advanced civilization.

SETI looked at KIC 8462852 for twelve hours per day in the frequency range of 1.0 to 10.0 gigahertz between October 15 and October 30. For a comparison of radio frequencies, your home Wi-Fi operates at 2.4 or 5.4 gigahertz, GPS at 1.575 gigahertz, some portable phones at 5.8 gigahertz, satellite TV at 11.7-12.2 gigahertz, Sirius radio around 2.33 gigahertz and cell phones 0.8 to 2.5 gigahertz. The frequencies scanned by SETI exclude our terrestrial television, FM radio, public service fire/police radios, and aircraft communications.

Not to anyone’s surprise, no signal of any type was found. Does this mean there are no structures orbiting the star or any intelligent life there? No, there are many reasons to not find a radio signal and there will be ongoing observations for years to come.

Exoplanets:

With KIC 8462852 titillating our imaginations, it is interesting think about what planets exist around others stars that could support life. To date, 1642 planets outside our solar system have been confirmed; there are 3787 planet candidates waiting for confirmation. This article will look at the confirmed exoplanets less than fifty lightyears away from our sun that could be habitable.

Gliese 163b is orbiting its parent star with two other planets. Located about 49 lightyears away, this is a super Earth weighing about seven times Earth’s mass. The star Gliese 163 is only forty percent of the sun’s mass making it a red dwarf. Because of this, Gliese 163b orbits much closer to the star, making its year only 25.63 of our days. It likely has a solid, rocky surface, but its atmosphere is still unknown. Look for this star system in the southern sky Dorado constellation. The planet is likely tidal locked to the star with the same side in perpetual daylight; the other side is always dark. Here, life would struggle being much closer to the star and its deadly solar flares.

At 42 lightyears, HD 40307g is the sixth, and farthest, planet from its star orbiting about the same distance as Venus in our solar system. This is another super Earth weighing in at seven times Earth and taking 197.8 days to orbit its star. HD 40307g is far enough from its star that it is not tidal locked and rotates on its axis with true day/night cycles making life a better possibility. It is unknown what type of atmosphere HD 40307g has. Look for HD 40307 in the Pictor constellation.

Being one of six planets, Gliese 667Cc is a bit under four times Earth’s mass and resides 24 lightyears away. Gliese 667Cc is part of a triple star system where the other two stars would be visible bright stars in the sky. Again, the host star is a red dwarf emitting mostly infra-red light. Orbiting the star in only 28.1 days, this planet is probably tidally locked. Perhaps a habitable zone would exist in the twilight between the perpetual burning hot day side and the freezing night side. Our sun would be visible from the planet. This triple star system can be found in the Scorpius constellation.

Only 16 lightyears away, Gliese 832c is in the top three of the habitability list. It shares the star with another Jupiter-sized planet. Gliese 882c orbits every 36 days and has a mass at least five times that of Earth’s. The Earth Similarity Index (ESI) of Gliese 832 c is 0.81 (Earth’s ESI is 1.0). But again, the planet is tidally locked. Orbiting a red dwarf, and depending upon its atmosphere, it could be Earth-like or, with a thicker atmosphere, more similar to Venus. Look in the constellation of Grus for this magnitude eight star.

The Kapteyn star system, 12 lightyears away, is more than twice as old as our solar system, so its potentially habitable planet, Kapteyn b, has had a long time for life to develop. That makes this star system only two billion years younger than the universe itself. But, like many habitable planets, we have found to date, Kapteyn b orbits a red dwarf every 48 days. At five times Earth’s mass, it likely has a rocky surface, but is tidally locked. If it has an Earth-like atmosphere, it would have a colder surface than Earth’s. There is a second planet in that star system orbiting farther out. Kapteyn is the second fastest moving star in the sky and belongs to the galactic halo, an extended cloud of stars orbiting our Galaxy in very elliptic orbits. This star was born in a dwarf Galaxy and later absorbed by the Early Milky Way. Look for Kapteyn in the southern constellation of Pictor.

 

 
Top of Page
TOP OF PAGE

Ad Rates  Back Issues  Contact Us  Front Page  Up Front  Animal News   Around Town  Sandoval Arts   Business Classifieds  Calendar   Community Bits  Community Center  Eco-Beat  Featured Artist  Gauntlet Health  Community Links  Night Sky  My Wife and Times  Public Safety  Real  People  Stereogram  Time Off  Youth