planets

Long-Term Transit Timing Monitoring and Refined Light Curve Parameters of HAT-P-13b

We present 10 new transit light curves of the transiting hot Jupiter HAT-P-13b, obtained during two observational seasons by three different telescopes. When combined with 12 previously published light curves, we have a sample consisting of 22 transit light curves, spanning 1,041 days across four observational seasons. We use this sample to examine the recently observed large-amplitude transit timing variations (Pal et al. 2011), and give refined system parameters.

Fulton et al. 2011, accepted by AJ

Planets and How They Formed

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The planets in our Solar System are believed to have formed from the same spinning disc of dust that formed the Sun. This disc, called the solar nebula, was composed mainly of hydrogen and helium, but also had other elements in smaller proportions. The nebula had a certain amount of angular momentum orbiting the forming Sun. Particles in the spinning disc began to clump together as gravity attracted them to each other.

The Scale of the Solar System

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Many images of the solar system do not do justice to how small the planets are relative to the Sun, or how distant they are from the Sun and each other. The solar system is really mostly empty space. The Toilet Roll Solar System activity helps give an idea of the relative distances between the planets. This Powers of Ten Demonstration shows relative sizes and distances by zooming out.

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Mass measurement of a single unseen star and planetary detection efficiency for OGLE 2007-BLG-050

We analyze OGLE-2007-BLG-050, a high magnification microlensing event (A ~ 432) whose peak occurred on 2 May, 2007, with pronounced finite-source and parallax effects. We compute planet detection efficiencies for this event in order to determine its sensitivity to the presence of planets around the lens star. Both finite-source and parallax effects permit a measurement of the angular Einstein radius \theta_E = 0.48 +/- 0.01 mas and the parallax \pi_E = 0.12 +/- 0.03, leading to an estimate of the lens mass M = 0.50 +/- 0.14 M_Sun and its distance to the observer D_L =
2009arXiv0907.3471B (Submitted ro A&A)

Masses and Orbital Constraints for the OGLE-2006-BLG-109Lb,c Jupiter/Saturn Analog Planetary System

We present a new analysis of the Jupiter+Saturn analog system, OGLE-2006-BLG-109Lb,c, which was the first double planet system discovered with the gravitational microlensing method. This is the only multi-planet system discovered by any method with measured masses for the star and both planets. In addition to the signatures of two planets, this event also exhibits a microlensing parallax signature and finite source effects that provide a direct measure of the masses of the star and planets, and the expected brightness of the host star is confirmed by Keck AO imaging, yielding masses of M_* =
(Submitted to ApJ)
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