Asteroid (3200) Phaethon: colors, phase curve, limits on cometary activity and fragmentation

We report on a multi-observatory campaign to examine asteroid 3200 Phaethon during its December 2017 close approach to Earth, in order to improve our measurements of its fundamental parameters, and to search for surface variations, cometary activity and fragmentation. The mean colors of Phaethon are B-V = 0.702 +/- 0.004, V-R = 0.309 +/- 0.003, R-I = 0.266 +/- 0.004, neutral to slightly blue, consistent with previous classifications of Phaethon as a F-type or B-type asteroid. Variations in Phaethon's B-V colors (but not V-R or R-I) with observer sub-latitude are seen and may be associated with craters observed by the Arecibo radar. High cadence photometry over phases from 20 to 100 degrees allows a fit to the values of the HG photometric parameters; H = 14.57 +/- 0.02, 13.63 +/- 0.02, 13.28 +/- 0.02, 13.07 +/- 0.02; G = 0.00 +/- 0.01, -0.09 +/- 0.01, -0.10 +/- 0.01, -0.08 +/- 0.01 in the BVRI filters respectively; the negative G values are consistent with other observations of F type asteroids. Light curve variations were seen that are also consistent with concavities reported by Arecibo, indicative of large craters on Phaethon's surface whose ejecta may be the source of the Geminid meteoroid stream. A search for gas/dust production set an upper limit of 0.06 +/- 0.02 kg/s when Phaethon was 1.449 AU from the Sun, and 0.2 +/- 0.1 kg/s at 1.067 AU. A search for meter-class fragments accompanying Phaethon did not find any whose on-sky motion was not also consistent with background main belt asteroids.Comment: Accepted by the Astronomical Journal, 15 pages, 8 figures, 1 animated figur

Asteroid (3200) Phaethon: Colors, Phase Curve, Limits on Cometary Activity, and Fragmentation

We report on a multiobservatory campaign to examine asteroid 3200 Phaethon during its 2017 December close approach to Earth, in order to improve our measurements of its fundamental parameters, and to search for surface variations, cometary activity, and fragmentation. The mean colors of Phaethon are B – V = 0.702 ± 0.004, V – R = 0.309 ± 0.003, and R – I = 0.266 ± 0.004, neutral to slightly blue, consistent with previous classifications of Phaethon as a F-type or B-type asteroid. Variations in Phaethon's B – V colors (but not V – R or R – I) with observer sublatitude are seen and may be associated with craters observed by the Arecibo radar. High-cadence photometry over phases from 20° to 100° allows a fit to the values of the HG photometric parameters; H = 14.57 ± 0.02, 13.63 ± 0.02, 13.28 ± 0.02, 13.07 ± 0.02; G = 0.00 ± 0.01, −0.09 ± 0.01, −0.10 ± 0.01, −0.08 ± 0.01 in the BVRI filters respectively; the negative G values are consistent with other observations of F-type asteroids. Light-curve variations were seen that are also consistent with concavities reported by Arecibo, indicative of large craters on Phaethon's surface whose ejecta may be the source of the Geminid meteoroid stream. A search for gas/dust production sets an upper limit of 0.06 ± 0.02 kg s^(−1) when Phaethon was 1.449 au from the Sun, and 0.2 ± 0.1 kg s^(−1) at 1.067 au. A search for meter-class fragments accompanying Phaethon did not find any whose on-sky motion was not also consistent with background main-belt asteroids

Towards Efficient Detection of Small Near-Earth Asteroids Using the Zwicky Transient Facility (ZTF)

We describe ZStreak, a semi-real-time pipeline specialized in detecting small, fast-moving near-Earth asteroids (NEAs) that is currently operating on the data from the newly-commissioned Zwicky Transient Facility (ZTF) survey. Based on a prototype originally developed by Waszczak et al. (2017) for the Palomar Transient Factory (PTF), the predecessor of ZTF, ZStreak features an improved machine-learning model that can cope with the $10\times$ data rate increment between PTF and ZTF. Since its first discovery on 2018 February 5 (2018 CL), ZTF/ZStreak has discovered $45$ confirmed new NEAs over a total of 232 observable nights until 2018 December 31. Most of the discoveries are small NEAs, with diameters less than $\sim100$ m. By analyzing the discovery circumstances, we find that objects having the first to last detection time interval under 2 hr are at risk of being lost. We will further improve real-time follow-up capabilities, and work on suppressing false positives using deep learning.Comment: PASP in pres

Особенности вазомоторной функции эндотелия у больных стабильной стенокардией с факторами риска (артериальной гипертензией, гиперхолестеринемией, курением)

ВАЗОМОТОРНАЯ СИСТЕМАЭНДОТЕЛИЙ /ФИЗИОЛЭПИТЕЛИЙСТЕНОКАРДИЯКОРОНАРНАЯ БОЛЕЗНЬГРУДНАЯ КЛЕТКА, БОЛИФАКТОРЫ РИСКАГИПЕРТЕНЗИЯКРОВЕНОСНЫХ СОСУДОВ БОЛЕЗНИГИПЕРХОЛЕСТЕРИНЕМИЯГИПЕРЛИПИДЕМИЯКУРЕНИЕ /ВРЕД ВОЗДТАБАКА УПОТРЕБЛЕНИЕ, РАССТРОЙСТВА ЗДОРОВЬ

Towards Efficient Detection of Small Near-Earth Asteroids Using the Zwicky Transient Facility (ZTF)

We describe ZStreak, a semi-real-time pipeline specialized in detecting small, fast-moving, near-Earth asteroids (NEAs), which is currently operating on the data from the newly commissioned Zwicky Transient Facility (ZTF) survey. Based on a prototype originally developed by Waszczak et al. (2017) for the Palomar Transient Factory (PTF), the predecessor of ZTF, ZStreak features an improved machine-learning model that can cope with the 10× data rate increment between PTF and ZTF. Since its first discovery on 2018 February 5 (2018 CL), ZTF/ZStreak has discovered 45 confirmed new NEAs over a total of 232 observable nights until 2018 December 31. Most of the discoveries are small NEAs, with diameters less than ~100 m. By analyzing the discovery circumstances, we find that objects having the first to last detection time interval under 2 hr are at risk of being lost. We will further improve real-time follow-up capabilities, and work on suppressing false positives using deep learning