Kevin Hardegree-Ullman

@kevinkhu

Exoplanets, cool stars, brown dwarfs. He/him/his.

Vrijeme pridruživanja: prosinac 2008.

Tweetovi

Blokirali ste korisnika/cu @kevinkhu

Jeste li sigurni da želite vidjeti te tweetove? Time nećete deblokirati korisnika/cu @kevinkhu

  1. Prikvačeni tweet

    NEW PAPER ALERT! "Scaling K2. I. Revised Parameters for 222,088 K2 Stars and a K2 Planet Radius Valley at 1.9 R⊕" (soon in ApJS!) This is the first paper in the "Scaling K2" series, with the ultimate goal of computing planet occurrence rates. But...

    Prikaži ovu nit
    Poništi
  2. Poništi
  3. K2 Planet Occurrence Rates, here we come...

    Prikaži ovu nit
    Poništi
  4. BUT WAIT.... THERE'S MORE! Go read "Scaling K2. II. Assembly of a Fully Automated C5 Planet Candidate Catalog Using EDI-Vetter", led by !

    Prikaži ovu nit
    Poništi
  5. Many thanks to , , , David R. Ciardi, and for their important contributions to this paper!

    Prikaži ovu nit
    Poništi
  6. This result would not have been easily identifiable without a uniform set of stellar parameters.

    Prikaži ovu nit
    Poništi
  7. This means that the Kepler result is not a fluke, and since K2 probes different regions in the Galaxy, this result is not exclusive to the Kepler field! Here's how the radius valley looks in relation to incident stellar flux (left), and compared Kepler (right).

    Prikaži ovu nit
    Poništi
  8. Using our new stellar parameters, we re-derived radii for 299 confirmed and 517 candidate planets and something magical happened: WE FOUND A DEFINITIVE PLANET RADIUS GAP FOR THE FIRST TIME IN A DATA SET OTHER THAN KEPLER!

    Prikaži ovu nit
    Poništi
  9. We used the Stefan-Boltzmann law to compute radii for AFGK stars, and absolute magnitude-radius relations from Mann+ 2015 for M dwarfs. In total we have new stellar parameters for 222,088 stars!

    Prikaži ovu nit
    Poništi
  10. Using the spectroscopic target photometry and parameters as a training set, we used machine learning to derive spectral types, temperatures, surface gravities, and metallicities for targets without a spectrum.

    Prikaži ovu nit
    Poništi
  11. The LAMOST pipeline provides spectral types, temperatures, surface gravities, and metallicities for A, F, G, and K stars, but not M dwarfs. Luckily, I know a thing or two about M dwarfs ().

    Prikaži ovu nit
    Poništi
  12. We updated some of the photometry in the EPIC using Pan-STARRS, used the database to cross-match Gaia and K2 targets, and cross-matched the K2 targets with LAMOST to find ~27,000 K2 targets with a spectrum.

    Prikaži ovu nit
    Poništi
  13. Gaia measured distances to 1.3 billion stars! But Gaia is not alone in the era of Big Astronomical Data™. Pan-STARRS DR2 is 1.6 petabytes of photometry, and LAMOST DR5 has over 9 million spectra!

    Prikaži ovu nit
    Poništi
  14. The Ecliptic Plane Input Catalog (EPIC; Huber+ 2016) characterized about ~300,000 stars for K2 mostly using proper motions and colors. Then, something completely expected happened. Gaia DR2 came and changed everything...

    Prikaži ovu nit
    Poništi
  15. K2 (revitalized Kepler spacecraft) stared at a bunch of different fields along the ecliptic plane for ~80 days each in search of planets transiting their host star. To measure the transiting planet radius, we first need to know the host star radius.

    Prikaži ovu nit
    Poništi
  16. Before we can do anything with the planets, we must know something about the stars that host them: KNOW THY STAR, KNOW THY PLANET! It is important to measure things like stellar radii, masses, temperatures, etc. in a homogeneous manner for occurrence rates.

    Prikaži ovu nit
    Poništi
  17. I appreciate the optimistic headline from CNN, and loathe the disingenuous clickbait from BGR regarding Spitzer. Frankly, I'm surprised (and happy) I haven't seen any headlines along the lines of "NASA kills $1.3 billion telescope."

    Poništi
  18. 1. velj

    Star Trek: Exploring New Worlds exhibit is coming to ! Can we do a panel about astronomers exploring new worlds at the exhibit? cc:

    Poništi
  19. 31. sij

    Today we bid adieu to another space telescope that helped kick start my research. joins Kepler in retirement, drifting along in their Earth-trailing orbits. Farewell my infrariend, thanks for all the brown dwarf and exoplanet follow-up!

    Poništi
  20. 30. sij
    Prikaži ovu nit
    Poništi

Čini se da učitavanje traje već neko vrijeme.

Twitter je možda preopterećen ili ima kratkotrajnih poteškoća u radu. Pokušajte ponovno ili potražite dodatne informacije u odjeljku Status Twittera.

    Možda bi vam se svidjelo i ovo:

    ·