exoplanets

All posts tagged exoplanets

TRAPPIST-1 Discovery

https://www.nasa.gov/press-release/nasa-telescope-reveals-largest-batch-of-earth-size-habitable-zone-planets-around

https://www.popularmechanics.com/space/deep-space/g40958720/exoplanets-in-the-milky-way/

https://exoplanets.nasa.gov/alien-worlds/exoplanet-travel-bureau/

https://exoplanets.nasa.gov/alien-worlds/strange-new-worlds/

Evidence of Long-term Period Variations in the Exoplanet Transit Database (ETD)

https://iopscience.iop.org/article/10.3847/1538-3881/ac959a

An artist’s concept of the hot-Jupiter exoplanet WASP-12b. Image credit: NASA / ESA / G. Bacon, STScI / C. Haswell, Open University.
Transit timing for WASP-12 b from Hagey et al. (2022).

able 4. Model Comparison for Secondary Analysis—Data Variance for ETD Transit Times

TargetDecay Rate1σ Unc.BIClinearBICdecayΔBIC
 (ms yr−1)(ms yr−1)   
WASP-12 b−34.84.9223.7202.7−21.0
HAT-P-19 b−641780.678.2−2.4
TrES-1 b−16.03.773.368.3−5.0
WASP-4 b−6.72.462.662.70.1
TrES-2 b−22.08.0159.0160.31.3
TrES-5 b−2511118.3120.52.2
HAT-P-32 b−321295.596.71.2
WASP-10 b−10.17.6131.6135.53.9
WASP-43 b3.54.0126.5130.94.4
TrES-3 b0.011.9227.8233.15.3
Model comparison of the results from the reduced data of the top 10 systems after replacing the ETD transit center uncertainties with the standard deviation of the nominal timing residuals. A negative ΔBIC value favors the orbital decay model. From Hagey et al. (2022).

In 1986, superstars Lionel Richie and Michael Jackson won a Grammy for “Best Song of the Year” for “We are the World“, a single recorded to support the African charity USA for Africa (https://usaforafrica.org/) to provide food and relief aid to starving people in Africa, specifically Ethiopia where a famine raged. With sales in excess of 20 million copies, it is the eighth-bestselling physical single of all time, and it immediately generated 60 million dollars.

But 1986 also marked the 300th anniversary of one of the most popular science books of all time, Conversations on the Plurality of Worlds. And a NASA mission just over the horizon may turn the sci-fi conversations about alien life from this classic pop-sci book into science fact.

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Image of Sirius A and Sirius B taken by the Hubble Space Telescope. Sirius B, which is a white dwarf, can be seen as a faint point of light to the lower left of the much brighter Sirius A. From https://en.wikipedia.org/wiki/White_dwarf.

White dwarf stars have been a mystery since they were first discovered. Extraordinarily hot and compact, the engima of white dwarfs was unraveled largely through the herculean efforts of the Harvard computers. Astronomers now know white dwarfs are the final stage of a violent aging process for Sun-like stars. And though astronomers originally expected such violence would spell doom for any planets in orbit, mounting discoveries show that some planets at least can survive this cataclysmic descent into stellar senescence. Whether any life survives on those planets is another matter.

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Illustration of a planet being accreted by its host star. From https://aasnova.org/2017/07/12/wasp-12b-and-its-possible-fiery-demise/.

When the first exoplanets were discovered, astronomers were shocked to find gas giants like Jupiter but zipping around their host stars in days rather than years. These hot Jupiters orbited so close that astronomers worried they might eventually spiral into their stars. Although no one has yet seen a planet disappear, mounting circumstantial evidence suggests perhaps 35% of stars actually do consume their planetary children.

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The TESS Spacecraft.

At our journal club last week, we discussed the discovery of a new warm Jupiter from the TESS Mission.

TESS is the successor to the wildly successful Kepler/K2 Mission and is designed to find exoplanets using the same technique as Kepler – looking for their shadows as planets pass in front of their host stars, i.e. the transit technique.

Sadly, the Kepler spacecraft was officially shut down two weeks ag0 because it ran out of fuel, but TESS, launched last March, is off and running, having already discovered about half a dozen new planets.

One of those planets, we discussed in journal club on Friday – a planet orbiting the star HD1397. The gas giant planet is about the same size as Jupiter but half the mass, making it significantly less dense than Saturn.

The planet also has an unusually eccentric or stretched-out orbit that swings very near its host star, passing to within 8 stellar radii from its star at its closest point. By contrast, the Earth is 200 stellar radii away from the Sun.

If this planet had been discovered 20 years ago, it would have completely stumped astrophysicists, and many would likely have doubted its existence. Nowadays, though, such strange planets are practically the norm in exoplanet astronomy.

So with HD1397 b’s discovery, the exoplanet train rumbles on, and we should expect thousands upon thousands more bizzarities from TESS that will, like Kepler’s discoveries, again re-write the planetary rulebook.


At our research group meeting, we also discussed the art of scientific presentations. I’ve pasted the example presentation I gave below.