The effects of birth environment on planetary systems Melvyn B. - PowerPoint PPT Presentation

The effects of birth environment on planetary systems Melvyn B. Davies Department of Astronomy and Theoretical Physics Lund Observatory www.astro.lu.se

Five things to remember about exoplanetary systems Melvyn B. Davies Department of Astronomy and Theoretical Physics Lund Observatory www.astro.lu.se

There are many flat and/or low eccentricity planetary systems 1) The Solar System 2) Lovis et al. (2010) list of multiple systems 3) Kepler systems Lissauer et al. 2011; Tremaine & Dong 2012; Johansen et al. 2012; Fang & Margot 2012

Making everything from 3p systems 10 Increasing 8 inclination 10.0 spread 9.0 6 2t3p/3t3p 8.0 7.0 Kepler sees 4 6.0 more 1t Kepler 5.0 than come 4.0 2 from 3p 3.0 2.0 0.0 0 0 5 10 15 20 25 30 1t3p/3t3p (Johansen, Davies, Church & Holmelin 2012)

There are many flat and/or low eccentricity planetary systems 1) The Solar System 2) Lovis et al. (2010) list of multiple systems 3) Kepler systems Lissauer et al. 2011; Tremaine & Dong 2012; Johansen et al. 2012; Fang & Margot 2012 But some exoplanets are also observed on eccentric orbits... are they de-stabilised by encounters?

Encounters within birth environments happen interestingly often Timescale for a given star to undergo an encounter is ◆✓ 10 3 AU ✓ 100 pc � 3 ◆✓ ◆✓ M � ◆ V ∞ τ enc ' 3 . 3 ⇥ 10 7 yr n 1 km / s R min M t Beware of the average: lumpiness can make a difference. (e.g. Malmberg et al. 2007; Davies et al. 2014)

Fraction of solar-like stars suffering encounters Close fly-by Binary earlier Binary today WS-10 ~0.10 ~0.05 ~0.03 CL-10 ~0.15 ~0.20 ~0.15 WS-all ~0.20 ~0.20 ~0.03 CL-all ~0.20 ~0.50 ~0.10 (Church, Davies & Bonnerot, in prep.) In other words: fly-bys and exchanges into binary systems can happen interestingly often.

Encounters can mess up planetary systems

The four gas giants 10 8 years after fly-by (r Min < 100 AU) (Malmberg, Davies & Heggie 2011; see also Scharf & Menou 2009; Veras, Crepp & Ford 2009)

The four gas giants in a binary (Malmberg, Davies & Chambers 2007; Malmberg & Davies 2009)

In Kepler zone many planetary systems are multiple but most hot Jupiters are single

(Mustill, Davies & Johansen 2015)

Injecting planets in from further out can mess up inner system 3p+J=np or J 3p+np=p? (Mustill, Davies & Johansen 2015; Mustill, Davies & Johansen in prep.)

Summary 1. Planetary systems are often flat 2. Encounters happen in birth environments 3. Encounters mess up planetary systems 4. Kepler sees multiple p, single J, or single p 5. 3p+J or 3p+np may make what we see