HD 40307 g: One of Three Habitable Planet Image Releases by NASA in 2014

Summary: NASA's fictitious Exoplanet Travel Bureau poster promotes possibly habitable exoplanet HD 40307 g as a place with "the gravity of a super Earth."

Exoplanet Travel Bureau poster for HD 40307 g: 1930s Works Progress Administration retro-style poster by NASA/JPL-Caltech

A celestial object of interest: location, location, location!

Henry Draper (March 7, 1837-Nov. 20, 1882) Catalogue designation 40307 g appears on two prestigious releases by the National Space and Aeronautics Agency. The photogenic extra-solar system planet brightens one of three habitable planet image releases at year-end 2014. NASA scientists consider HD 40307 g a spatial body of interest. They deem as interesting distance, revolution, rotation, shape and size.

At a 42 light-years' (399,000,000,000,000 kilometers; 246,960,000,000,000 miles) distance from Earth, HD 40307 g effectuates orbits around a K-type star within the Southern Celestial Hemisphere's easel-like constellation Pictor ("painter") invented and named in 1752 by Abbé Nicolas Louis de La Caille (Dec. 28, 1713 to March 21, 1762) for Mémoires de l'Académie Royal des Sciences in Paris, France.

In the correct place at the correct time

HD 40307 g goes around its hydrogen-burning star every 197.8 terrestrial days. It holds to an elliptical planetary-solar distance of 55,800,000 miles (90,000,000 kilometers). Its sun is a low-luminosity, main-sequence, orange-spectrum dwarf with lines faint in hydrogen, robust in neutral metals (iron, manganese, silicon) and welcome to titanium oxide and with mass and radius three-fourths that of Earth's sun, representation universe-wide at thrice or quadruple that of the sun's G-type presence, 62 to 67 percent radiation emissions of Earth's sun, stability of 15,000,000,000 to 30,000,000,000 years, as opposed to 10,000,000,000 years for Earth's sun, and temperatures just below 4977 degrees Kelvin (4703.85 degrees Celsius, 8498.93 degrees Fahrenheit) on the Kelvin scale named for William Thomson, 1st Baron Kelvin (June 26, 1824 to Dec. 17, 1907).

The usual suspects: days and nights, liquid water

Scientists judge HD 40307 g potentially habitable, and supportive of liquid-state water, because of astronomical distance, orbital shape and planetary revolution.

They know that HD 40307 g is sufficiently distant from its sun and substantial, at eight times Earth's mass, to suggest alternation of days and nights as well as articulation of temperatures from 1.4 to 126 degrees F (minus 17 to 52 degrees C) and avoidance of one-sided facing and tidal locking.

At the same time, scientists lack unanimity in their suppositions, whose descriptions contentiously interpret evidentiary paths of indirect analysis, such as super-Earth exo-planets gravitationally tugging low-mass host stars, through La Silla Observatory's High Accuracy Radial velocity Planet Searcher (HARPS) spectrograph in central Chile's Coquimbo Region.

Water, water everywhere, but no drops to drink?

Astronomers such as Professors Rory Barnes of the United States of America's University of Washington, Guillem Anglada-Escude of Germany's University of Goettingen and Hugh Jones and Mikko Tuomi of England's University of Hertfordshire mull HD 40307 g's composition, gravity, surface and temperatures. Their best guesses nudge the extremes of a rocky Earth or of a warm Neptune.

They owe everything to location, at which HD 40307 b, c, d, e and f may be migrants too close to their host and too hot for liquid water, and nothing to the company that HD 40307 g keeps. They provide frameworks for the answers soon to come from cutting-edge, deep space-imaging telescopes mounted on tomorrow's satellites and spacecraft.

artistic depiction of potentially habitable exoplanet HD 40307 g: illustration by CiLiNDrO, CC BY SA 3.0, via DeviantArt

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

HD 40307 g: Experience the gravity of a super earth ~ NASA/JPL-Caltech, Public Domain, via NASA Planet Quest @ http://planetquest.jpl.nasa.gov/image/187

HD40307g: CiLiNDrO, CC BY SA 3.0, via DeviantArt @ http://cilindr0.deviantart.com/art/HD-40307g-336848398

For further information:

Marriner, Derdriu. 11 February 2016. "NASA Space Tourism Posters Tout Earth and Other Exotic Cosmic Locales." Earth and Space News. Thursday.
Available @ https://earth-and-space-news.blogspot.com/2016/02/nasa-space-tourism-posters-tout-earth.html