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Assorted Personal Notations, Essays, and Other Jottings

Posts Tagged ‘barnard’s star

[BLOG] Some Thursday links

  • Bad Astronomer Phil Plait shares a lovely photo of the Earth peeking out from behind the far side of the Moon.
  • At the Broadside Blog, Caitlin Kelly shares lovely photos of delicate ice and water taken on a winter’s walk.
  • Centauri Dreams looks at the study by Chinese astronomers who, looking at the distribution of Cepheids, figured out that our galaxy’s disk is an S-shaped warp.
  • D-Brief notes new evidence that melting of the Greenland ice sheet will disrupt the Gulf Stream.
  • L.M. Sacasas at The Frailest Thing takes issue with the uncritical idealization of the present, as opposed to the critical examination of whatever time period we are engaging with.
  • Gizmodo notes that an intensive series of brain scans is coming closer to highlighting the areas of the human brain responsible for consciousness.
  • Mark Graham links to new work of his, done in collaboration, looking at ways to make the sharing economy work more fairly in low- and middle-income countries.
  • JSTOR Daily notes how the mystic Catholicism of the African kingdom of Kongo may have gone on to inspire slave-led revolutions in 18th century North America and Haiti.
  • Lawyers, Guns and Money looks at an exhibition examining the ambitious architecture of Yugoslavia.
  • The Map Room Blog links to a cartographer’s argument about the continuing importance of paper maps.
  • Marginal Revolution shares one commenter’s perception of causes or the real estate boom in New Zealand.
  • Neuroskeptic considers the role of the mysterious silent neurons in the human brain.
  • At NYR Daily, Guadeloupe writer Maryse Condé talks about her career as a writer and the challenges of identity for her native island.
  • Roads and Kingdoms shares a list of ten dishes reflecting the history of the city of Lisbon.
  • Starts With A Bang’s Ethan Siegel takes a look at the promise of likely mini-Neptune Barnard’s Star b as a target for observation, perhaps even life.
  • Window on Eurasia shares the perfectly plausible argument that, just as the shift of the Irish to the English language did not end Irish identity and nationalism, so might a shift to Russian among Tatars not end Tatar identity.

[BLOG] Some Friday links

  • Architectuul looks at the modernist works of Spanish Antonio Lamela, building after the Second World War under Franco.
  • Centauri Dreams considers the possibility of life-supporting environments on Barnard’s Star b, a frozen super-Earth.
  • The Crux takes a look at how, and when, human beings and their ancestors stopped being as furry as other primates.
  • D-Brief notes the Russian startup that wants to put advertisements in Earth orbit.
  • Drew Ex Machina takes a look at the Soyuz 4 and 5 missions, the first missions to see two crewed craft link up in space.
  • Far Outliers notes</a the extent to which, before the Opium War, knowledge of Chinese language and culture was kept strictly secret from Westerners at Canton.
  • L.M. Sacasas at The Frailest Thing notes the ironies of housing a state-of-the-art supercomputers in the deconsecrated Torre Girona Chapel in Barcelona.
  • Gizmodo notes a new study claiming that the rings of Saturn may be less than a hundred million years old, product of some catastrophic obliteration of an ice moon perhaps.
  • Joe. My. God. notes the death of Pulitzer-winning lesbian poet Mary Oliver.
  • JSTOR Daily takes a look at the rising prominence of hoarding as a psychological disorder.
  • Language Hat shares a manuscript more than a hundred pages long, reporting on terms relating to sea ice used in the Inupiaq language spoken by the Alaska community of Kifigin, or Wales.
  • Language Log examines the etymology of “slave” and “Slav”. (Apparently “ciao” is also linked to these words.)
  • Lawyers, Guns and Money notes that Buzzfeed was right to claim that Trump ordered his lawyer to lie to Congress about the Moscow Trump Tower project.
  • Marginal Revolution notes a serious proposal in the Indian state of Sikkim to set up a guaranteed minimum income project.
  • Frank Jacobs at Strange Maps links to a map showing visitations of the Virgin Mary worldwide, both recognized and unrecognized by the Vatican.
  • Starts With A Bang’s Ethan Siegel notes the continuing controversy over the identity of AT2018cow.
  • Window on Eurasia suggests that Russians have more to fear from a Sino-Russian alliance than Americans, on account of the possibility of a Chinese takeover of Russia enabled by this alliance.

[NEWS] Five D-Brief links: white dwarfs, FRBs, Barnard’s Star b, AT2018cow, termites

  • A new study by astronomers suggests that white dwarfs evolve over eons as they cool into immense crystals. D-Brief reports.
  • Canadian astronomers have found a second mysterious repeating fast radio burst. D-Brief reports.
  • Subsurface environments suitable for life could conceivably exist at Barnard’s Star b. D-Brief reports.
  • Astronomers observing the mysterious AT2018cow event in nearby dwarf galaxy CGCG 137-068t may have witnessed the formation of a compact object, a black hole or a neutron star. D-Brief reports.
  • The turning of the earth wrought by termite hives in tropical rainforests may help protect these environments from drought. D-Brief reports.

[BLOG] Some Friday links

  • The Buzz celebrates Esi Edugyan’s winning of the Giller Prize for the second time, for her amazing novel Washington Black.
  • Centauri Dreams notes the unusual rings of outer-system body Chariklo.
  • The Crux looks at the long history of unsuccessful planet-hunting at Barnard’s Star, concentrating on the disproved mid-20th century work of Peter Van De Kamp.
  • D-Brief notes evidence that Mars knew catastrophic floods that radically reshaped its surface.
  • Bruce Dorminey visits and explores Korea’s ancient Cheomseongdae Observatory.
  • The Everyday Sociology Blog notes the death of long-time contributor Peter Kaufman.
  • L.M. Sacasas at The Frailest Thing considers the things–quiet, even–that modernity can undermine before transforming into a commodity.
  • Imageo notes that global warming has continued this American Thanksgiving.
  • Joe. My. God. notes the sour grapes of the Family Research Council at the success of the moving film about “gay conversion therapy”, Boy Erased.
  • JSTOR Daily links to a paper considering if the zeitgeist of the world is into major monuments.
  • Language Log considers a news report of “arsehole” geese in Australia. As a Canadian, all I can say is that geese are birds that know they are dinosaurs.
  • The LRB Blog reports from the scene of the recent unrecognized elections in the city of Donetsk, run by a pro-Russian regime.
  • The Map Room Blog reports on how Atlas Obscura is exhibiting some amazing maps produced in Dungeons and Dragons campaigns.
  • Marginal Revolution links to a paper noting how black teachers can help boost achievements among black students.
  • The New APPS Blog looks at how the political economy of our time combines with social media to atomize and fragment society.
  • Nicholas Lezard at the NYR Daily talks about his experience of anti-Semitism, as a non-Jew, in the United Kingdom.
  • Casey Dreier at the Planetary Society Blog suggests families would do better to talk about space at Thanksgiving than about politics, and shares a list of subjects.
  • Drew Rowsome talks about the frustrations and the entertainment involved with Bohemian Rhapsody.
  • Window on Eurasia notes that fifty thousand ethnic Kyrgyz are being held in the Xinjiang camps of China.
  • Arnold Zwicky shares some Thanksgiving holiday cartoons by Roz Chast.

[NEWS] Five links about Barnard’s Star b (#barnardb)

Today’s announcement of the discovery of Barnard’s Star b, a super-Earth orbiting the nearby red dwarf of Barnard’s Star a mere six light-years away from the Earth, is exciting. Not only is this one of the closest exoplanets to our own solar system, this is exciting news about the Barnard’s Star system, finally finding an actual exoplanet decades after the mistaken identification of exoplanets here.

M. Kornmesser’s artistic impression of this world in orbit around its star is lovely.


  • The official European Southern Observatory announcement of the discovery of a super-Earth orbiting Barnard’s Star is exciting news!
  • Centauri Dreams picks up the exciting news about Barnard b, as does Bruce Dorminey.
  • D-Brief has an extended look into the background of the astronomical project responsible for determining the near-certainty of the existence of Barnard b.
  • D-Brief notes that, unfortunately, Barnard b orbits too far from its parent red dwarf star to support anything like Earth-like conditions, to say nothing of the risk to life from occasional massive stellar flares.

Written by Randy McDonald

November 14, 2018 at 11:20 pm

[BLOG] Some Wednesday links

  • Charley Ross notes the belated recovery and identification of Margret Dodd, four decades after her abduction and more than two after her body was found.
  • D-Brief notes that the Pale Red Dot is extending their exoplanet search from Proxima Centauri to include Barnard’s Star and Ross 154.
  • Dangerous Minds shares colour autochromes of American women from a century ago.
  • Gizmodo notes more evidence suggesting Mars’ moons, Phobos and Deimos, are legacies of a massive Mars impact.
  • The LRB Blog looks back at the 1951 “Festival of Britain”.
  • Roads and Kingdoms’ Karen Dias looks at a girls’ soccer team in Haryana, north India.
  • Peter Rukavina shares a sketch of some of the work being done at Province House.
  • The Volokh Conspiracy looks at the timeline for Russian influence on the Trump campaign.
  • Window on Eurasia comes to worrying conclusions about ethnic conflict in Daghestan.

[BLOG] Some Monday links

  • blogTO shares photos of Yonge and Bloor from the 1960s.
  • Crooked Timber’s Corey Robin looks at trigger warnings in education.
  • The Dragon’s Gaze notes that Barnard’s Star cannot support a massive planet in its orbit.
  • The Dragon’s Tales has more on the Ukrainian war.
  • The Everyday Sociology Blog examines racism.
  • Far Outliers notes how the Ryukyus fared under American occupation.
  • A Fistful of Euros looks at the divergences of Spain and the United Kingdom interest rate-wise.
  • Geocurrents notes another small Kurdish-speaking sect.</li
  • Joe. My. God. notes an attempt to appeal the Irish marriage referendum.
  • The Map Room’s Jonathan Crowe notes a 2016 conference on fictional maps in Poland.
  • Marginal Revolution notes a microhistory of a block in New York City.
  • The Power and the Money examines Ukraine’s debt negotiations and argues that Russia is not as big a player in global oil markets as it might like.
  • The Russian Demographics Blog and Window on Eurasia note how ethnic Russians in Ukraine are continuing to identify as ethnic Ukrainians.
  • Understanding Society considers realism in social sciences.
  • Whatever’s John Scalzi talks about the Sad Puppies.
  • Window on Eurasia notes Tatarstan’s potential separatism and suggests some Russian Germans still want an autonomy.

[BLOG] Some Friday links

  • Andrew Barton at Acts of Minor Treason observes that the invade-the-United-States meme hasn’t become more plausible over time, the differences between the first Red Dawn (featuring a Soviet invasion) and the second (featuring North Korea) being a case in point.
  • Centauri Dreams offers more commentary on the non-detection of Earth-size planets orbiting Barnard’s Star.
  • Far Outliers posts from Bill Hayton’s book on Vietnam describing how the entrepreneurial southern provinces of Vietnam helped save the national economy after reunification.
  • Geocurrents notes the revival of Berbera, city in unrecognized Somaliland, over the past two decades.
  • Marginal Revolution notes the importance of the shipping pallet.
  • Can oil really make things better for Tajikistan, wonders?

[BRIEF NOTE] On the apparent lack of Earth-size or larger planets at Barnard’s Star

Over at Facebook, James Nicoll shared the paper by Jieun Choi et al, “Precise Doppler Monitoring of Barnard’s Star”. Barnard’s Star, for those of you unfamiliar with this object (Sol Station and Wikipedia have much more to say), is a dim, ancient red dwarf star about ten billion years old, more than twice the age of our our sun and only a small fraction of a percent as bright. 6 light years away, Barnard’s Star is the second-closest star to our own sun after Alpha Centauri and so has been a common target of study for astronomers and a setting for science fiction writers–Robert Forward’s Rocheworld is the most famous book set about Barnard’s Star, but I can think of others.

Because of its proximity, Barnard’s Star has been a target for planet-hunters for decades. Most famously, in the mid-20th century American astronomer Peter Van De Kamp claimed to have detected two gas giant planets orbiting Barnard’s Star. As the state of the technology advanced, however, these very early claims have been disproved. At present, using the latest data, it’s uncertain if any substantial worlds orbit Barnard’s Star.

We present 248 precise Doppler measurements of Barnard’s Star (Gl 699), the second nearest star system to Earth, obtained from Lick and Keck Observatories during 25 years between 1987 and 2012. The early precision was 20 \ms{} but was 2 \ms{} during the last 8 years, constituting the most extensive and sensitive search for Doppler signatures of planets around this stellar neighbor. We carefully analyze the 136 Keck radial velocities spanning 8 years by first applying a periodogram analysis to search for nearly circular orbits. We find no significant periodic Doppler signals with amplitudes above $\sim$2 \ms{}, setting firm upper limits on the minimum mass (\msini) of any planets with orbital periods from 0.1 to 1000 days. Using a Monte Carlo analysis for circular orbits, we determine that planetary companions to Barnard’s Star with masses above 2 \mearth{} and periods below 10 days would have been detected. Planets with periods up to 2 years and masses above 10 \mearth{} (0.03 \mjup) are also ruled out. A similar analysis allowing for eccentric orbits yields comparable mass limits. The habitable zone of Barnard’s Star appears to be devoid of roughly Earth-mass planets or larger, save for face-on orbits. Previous claims of planets around the star by van de Kamp are strongly refuted. The radial velocity of Barnard’s Star increases with time at $4.515\pm0.002$ \msy{}, consistent with the predicted geometrical effect, secular acceleration, that exchanges transverse for radial components of velocity.

As the paper notes, this is something of an anomaly, since red dwarfs as a class have been found to commonly host planets, including worlds the size of Neptune or even Earth. Barnard’s Star, though, perhaps on account of its age and its very low metallicity, does not share in this trend of stars of its class.

Written by Randy McDonald

August 16, 2012 at 4:12 pm

[LINK] “Discovery of the Smallest Exoplanets: The Barnard’s Star Connection”

Science Daily’s report on the discovery of the planetary system of red dwarf KOI-961 explores how that star’s similarities to Barnard’s Star–a nearby red dwarf, second-closest star to our solar system after the three of Alpha Centauri, itself believed to host planets by earlier generations of planet-hunters–helped astronomers build a model for KOI-961’s system.

The team used data from NASA’s Kepler mission combined with additional observations of a single star, called KOI-961, to determine that it possesses three planets that range in size from 0.57 to 0.78 times the radius of Earth. This makes them the smallest of the more than 700 exoplanets confirmed to orbit other stars.

In their investigation of KOI-961, which is about 130 light years away in the Cygnus constellation, the astronomers found that it is nearly identical to Barnard’s star, which is only six light years away in the constellation Ophiuchus. This similarity allowed them to use information about Barnard’s star, which was discovered in 1916 by Vanderbilt astronomer E.E. Barnard, to determine the mass, size and luminosity of the distant star. These values, in turn, were used to determine the size of the three new exoplanets.

“Barnard’s star and KOI-961 are both M dwarfs, which are also known as red dwarfs. This is the smallest category of stars. They are popular targets for exoplanet hunters because their small size makes it easier to detect Earth-sized planets,” said Keivan Stassun, the professor of astronomy who headed the Vanderbilt contingent. The other Vanderbilt scientists involved were Research Assistant Professors Joshua Pepper and Leslie Hebb.

From the 1960’s through the 1980’s, astronomers thought that Barnard’s star also had a planetary system — specifically one or two planets larger than Jupiter. If their existence had been verified, it would have been a scientific first, but the evidence was ultimately discredited. Today, advances in telescope technology and image processing allow astronomers to identify stars with exoplanets with considerable confidence.

[. . .]

Once the size of the star was established, the team used the Kepler data to calculate that the three exoplanets range from the size of Mars to slightly more than three-quarters the size of Earth. They also determined that these planets orbit the star with periods ranging from a half day to two days. Such short periods mean that all three orbit so close to their star that they must be too hot for liquid water to exist and life to evolve, the astronomers calculate.

The diminutive dimensions of this planetary system prompted John Johnson, the principal investigator of the research from NASA’s Exoplanet Science Institute at Caltech, to comment, “The really amazing thing about this system is that the closest size comparison is to Jupiter and its moons.” (KOI-961 is just 70 percent bigger than Jupiter and its exoplanets are comparable in size and have similar orbital periods to the Galilean moons that circle the Jovian planet.)

Sol Station’s profile of Barnard’s Star, linked above, suggests that a habitable world orbiting that star would need to have an orbit of roughly one to three weeks.

Written by Randy McDonald

January 12, 2012 at 10:57 pm