Friday, July 21, 2017

NASA-funded Backyard Worlds: Planet 9 Finds Brown Dwarf WISEA J110125.95+540052.8.

One night three months ago, Rosa Castro finished her dinner, opened her laptop, and uncovered a novel object that was neither planet nor star. Therapist by day and amateur astronomer by night, Castro joined the NASA-funded Backyard Worlds: Planet 9 citizen science project when it began in February -- not knowing she would become one of four volunteers to help identify the project's first brown dwarf, formally known as WISEA J110125.95+540052.8.


Wednesday, July 19, 2017

Can Dark Matter Form Planets?

Dark stars may not just be for Grateful Dead fans anymore.

In a new paper uploaded to arXiv, Rutgers University astrophysics professor Matthew R. Buckley puts forth a truly wild hypothesis: It might be possible to build worlds out of dark matter.

Monday, July 17, 2017

Trappist-1h MIGHT Have Once Been Habitable

A University of Washington-led international team of astronomers has used data gathered by the Kepler Space Telescope to observe and confirm details of the outermost of seven exoplanets or-biting the star TRAPPIST-1.

They confirmed that the planet, TRAPPIST-1h, orbits its star every 18.77 days, is linked in its orbital path to its siblings and is frigidly cold. Far from its host star, the planet is likely uninhabit-able -- but it may not always have been so.

Monday, July 10, 2017

If Humanity will Reach the Nearest Stars in the Next Century, Where are the Aliens?

Relativistic Generalization of the Incentive Trap of Interstellar Travel with Application to Breakthrough Starshot



As new concepts of sending interstellar spacecraft to the nearest stars are now being investigated by various research teams, crucial questions about the timing of such a vast financial and labor investment arise. If humanity could build high-speed interstellar lightsails and reach α Centauri 20 yr after launch, would it be better to wait a few years, then take advantage of further technology improvements and arrive earlier despite waiting? The risk of being overtaken by a future, faster probe has been described earlier as the incentive trap. Based on 211 yr of historical data, we find that the speed growth of artificial vehicles, from steam-driven locomotives to Voyager 1, is much faster than previously believed, about 4.72 % annually or a doubling every 15 yr. We derive the mathematical framework to calculate the minimum of the wait time to launch t plus travel time τ(t) and extend it into the relativistic regime. We show that the t + τ(t) minimum disappears for nearby targets. There is no use of waiting once we can reach an object within about 20 yr of travel, irrespective of the actual speed. In terms of speed, the t + τ(t) minimum for a travel to α Centauri occurs at 19.6 % the speed of light (c), in agreement with the 20 % c proposed by the Breakthrough Starshot Initiative. If interstellar travel at 20 % c could be achieved within 45 yr from today and the kinetic energy be increased at a rate consistent with the historical record, then humans can reach the ten most nearby stars within 100 yr from today.

Friday, July 7, 2017

Does Proxima b have a Sister World?

Proxima Centauri b may not be alone out there.

The 2016 announcement of Proxima Centauri b was a watershed moment in exoplanet research. Not only had researchers found a potentially habitable Earth-mass planet, but it was at the nearest star to Earth. This means it could be one of the easiest systems to study using future telescopes.

But researchers are now looking into some promising signals suggesting there are more planets lurking in the system.

Monday, July 3, 2017

Could Exoplanets Around Neutron Stars be Habitable?

Neutron Star Planets: Atmospheric processes and habitability


Patruno et al

Of the roughly 3000 neutron stars known, only a handful have sub-stellar companions. The most famous of these are the low-mass planets around the millisecond pulsar B1257+12. New evidence indicates that observational biases could still hide a wide variety of planetary systems around most neutron stars. We consider the environment and physical processes relevant to neutron star planets, in particular the effect of X-ray irradiation and the relativistic pulsar wind on the planetary atmosphere. We discuss the survival time of planet atmospheres and the planetary surface conditions around different classes of neutron stars, and define a neutron star habitable zone. Depending on as-yet poorly constrained aspects of the pulsar wind, both Super-Earths around B1257+12 could lie within its habitable zone.