Planetary systems across the Milky Way. Credit: M. Kornmesser, ESO
(full-size image available here)
Years in Review
Six new or resurrected exoplanetary systems within 20 parsecs, including a low-mass planet around the nearest star, a Solar System analog less than 8 parsecs away, and the return of Rho Coronae Borealis
2014: A Year of Small Wonders
(1/4/15)
A Super Jupiter for Aldebaran, a gas dwarf for the Hyades, terrestrial planets around Kepler-138, subterrestrials around Kepler-444, and the continuing mystery of Hot Jupiters
Water vapor over HAT-P-11b, conjoined
planetary systems, another candidate for Earth 2, and more
Kepler finds the Holy Grail, goes
hooey-bluey, and morphs into K2
More circumbinary planets, plus rumors of
a Hellworld around Alpha Centauri B
Celebrating the Kepler revolution in
exoplanetary astronomy
Solar System
A look at two different explanations for the unusual architecture of the inner Solar System
A third explanation for the unusual architecture of the inner Solar System, with a forceful refutation of the previous two
A new study questions the ability of the Nice Model to explain the architecture of our Solar System
Notes on the Dawn and New Horizons missions to the dwarf planets Ceres and Pluto, with plenty of photos
Evidence for an ancient ocean covering
the northern hemisphere of Mars
Notions of a life-friendly Hadean Eon are
challenged by a new view of the Late Heavy Bombardment
The evolution of our Solar System, from
its birth in a huge star cluster to the formation of Jupiter and Saturn
The later phases of our system’s
evolution, including the Grand Tack and the Late Heavy Bombardment
Spoiler alert: it’s REALLY weird and
nobody knows why
The Sun and the eight planets at their relative sizes
The Sun's Back Yard
The Ghost in the Window (10/31/15)
More Distant Exoplanetary Systems
The Nearest 20 Parsecs (3/27/16)
An overview of planetary systems in the Sun's immediate neighborhood
An overview of planetary systems in the Sun's immediate neighborhood
Potential formation scenarios and habitability of Proxima Centauri b, a terrestrial planet just discovered around the nearest star to our Sun
Alpha Centauri Bb is shown to be a ghost instead of a real planet, while two of the six planets proposed for HD 40307 have no support in the data
A transiting Super Earth for HD 219134, only 21 light years away, plus musings on planetology and system architectures
Another group of astronomers looks at this remarkable system and finds six planets instead of four
A third group of astronomers looks at this remarkable system and confirms only four planets
A new study finds only three planets, and none of them are in the habitable zone
A new study finds only two planets, and none of them are in the habitable zone
A rosy view – since superseded – of the planetary system proposed for GJ 667C, a nearby M dwarf
A closer look at the evidence for Alpha Centauri Bb
A team using the HARPS spectrograph reports the marginal detection of a Hellworld orbiting Alpha Centauri B
Just when we thought we knew our neighbors, we find out we’re wrong again
An overview of the space within 10 parsecs, focusing on controversies involving Epsilon Eridani, Fomalhaut, GJ 581, and GJ 667C
New radial velocity data confirm a sixth non-transiting planet in this benchmark high-multiplicity system
HIP 41378: Compact Planet Sampler (7/10/16)
HIP 41378: Compact Planet Sampler (7/10/16)
The latest release of Kepler data reveals a lot of well-baked but lonely little planets
Almost Jupiter (3/20/16)
Almost Jupiter (3/20/16)
Kepler-167, a mixed-mass system where all planets are observed in transit, inspires another look at Jupiter analogs
New data significantly revise the
parameters of the system’s six planets
The first circumbinary system with two
planets, one smaller than Neptune
Kepler-38b, the fourth circumbinary
planetary system to be announced
An overview of the exoplanetary zoo,
focusing on planetology and system architecture, just as the census passes 900
confirmed extrasolar planets
Planets across five orders of magnitude in mass
Planetology
K2 and the Tweens (7/4/16)
The K2 Mission has been reporting some very interesting planets
A summary of constraints on the characteristics of planets that could support water and life
The K2 Mission has been reporting some very interesting planets
A summary of constraints on the characteristics of planets that could support water and life
Daydream Destinations, Part 1 (4/9/16)
Continuing our cruise through fantastic films and literature for insights into the potential environments of exomoons and tidally locked planets
Exploring speculative fiction for insights into possibly habitable planets in binary systems, with nods to Battlestar Galactica and Firefly
Daydream Destinations, Part 2 (4/14/16)
Daydream Destinations, Part 2 (4/14/16)
The latest release of Kepler data shows that small planets are more numerous than gas giants in our Galaxy
Understanding the bloated radii of so
many small Kepler planets
Reality check on current concepts and
nomenclature for planets smaller than Uranus
A review of the theories that gave us
Super Earths, plus a pitch to use the term “gas dwarf” instead of Super Earth
or Mini Neptune for all those puffy little Kepler planets
A growing number of transit detections
reveal exoplanets smaller than Earth
System Architecture
An overview of the Sun's immediate neighborhood, plus comparisons between the local exoplanet population and two other samples: radial velocity detections between 20 and 200 parsecs and Kepler discoveries at all distances
Kepler-167, a mixed-mass system where all planets are observed in transit, inspires another look at Jupiter analogs
A new study tries to explain the architecture of WASP-47 by in situ formation
The first Hot
Jupiter with not one but two close companions in an ultra-compact design
A rare example of conjoined planetary
systems, the only known pair in which both stars host Hot Jupiters
Suddenly we have a respectable sample of
compact multiple systems containing both gas giants and low-mass planets – and
we need a theory to explain them
Giant planets appear inimical to the
survival of nearby objects in the mass range of Mars to Uranus, a situation
with major implications for system architectures and the existence of habitable
planets
A modest proposal for categorizing
planetary systems according to three basic architectural types
On the critical role of planet mass in
system architecture
A critical look at the concepts of "Solar System analogs" and "Jupiter analogs"
Protoplanetary Disks and In Situ Formation (11/5/16)
System Evolution
An introduction to current theories on the formation and evolution of planetary systems
Fundamental data on the short-lived clouds of dusty gas where planets are born, plus a review of the theory of in situ formation
Accumulating evidence that the evolving structures of protoplanetary disks offer a template for system architectures
Evolutionary Twist (12/19/15)
Evolutionary Twist (12/19/15)
A new study questions the ability of the Nice Model to explain the architecture of our Solar System
Notions of a life-friendly Hadean Eon are challenged by a new view of the Late Heavy Bombardment
The evolution of our Solar System, from its birth in a huge star cluster to the formation of Jupiter and Saturn
The later phases of our system’s evolution, including the Grand Tack and the Late Heavy Bombardment
Earth 2
A summary of constraints on the characteristics of planets that could support water and life
The latest candidate for Earth 2 does not
impress
Guess what: Kepler hasn’t actually found
any Earth-like planets orbiting Sun-like stars
Our first look at Kepler-438b and
Kepler-442b, and a look back at the other candidates
The discovery of Kepler-186f, described
as a potentially habitable Super Earth
The discovery of Kepler-62f, described as
a potentially habitable Super Earth
Parsing the Kepler team’s remarks about
Earth-like planets orbiting Sun-like stars
Four NASA photographs of our planet scaled
according to the mass-radius relationships of Unterborn et al. (2016). For
perspective, one photogenic but out-of-range object – Mars – is included at far
left.
This index of blog posts on Back Alley Astronomy is regularly updated to enable easy access to extensive content on extrasolar planets and planetary systems.
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