1 / 16

Massive planets in FU Orionis objects

Massive planets in FU Orionis objects. Giuseppe Lodato Institute of Astronomy, Cambridge. In collaboration with Cathie Clarke (IoA). Rise timescale: t rise ≈ 1 yr (FU Ori and V1057 Cyg) t rise ≈ 20 yr (V1515 Cyg). Decay timescale: t decay ≈ 10 yr (V1057 Cyg)

marthaw
Télécharger la présentation

Massive planets in FU Orionis objects

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Massive planets in FU Orionis objects Giuseppe Lodato Institute of Astronomy, Cambridge In collaboration with Cathie Clarke (IoA)

  2. Rise timescale: trise≈ 1 yr (FU Ori and V1057 Cyg) trise ≈ 20 yr (V1515 Cyg) Decay timescale: tdecay≈ 10 yr (V1057 Cyg) tdecay ≈ 50-100 yr (FU Ori and V1515 Cyg) FU Orionis objects • Large outbursts: DL≈ 2-3 orders fo magnitude • Sudden increase in the mass accretion rate in the circumstellar disc • Accretion disc SED fit the observation for l<10mmKenyon & Hartmann 1991 • Double peaked optical - near IR line profiles

  3. Outburst mechanism • Tidal interaction with a companion star Bonnel & Bastien 1992 • Gravitational instability in a massive disc Armitage, Livio & Pringle 2001 • Thermal instability Clarke, Lin & Papaloizou 1989 Bell & Lin 1994, Bell et al 1995

  4. Unstable branch Stable branches Limit cycle instability Outwardly propagating front: slow Inwardly propagating front: fast m=nS

  5. Time-scale problem for thermal instability models • Bell & Lin (1994): accurate vertical structure calculations • SA and SB are strongly increasing function of R: instability triggered close to the inner edge • Slow rise timescale: trise≈ 10 yr • A fast rise time would be achieved if Rtrig ≈ 10 Ro

  6. Clarke & Armitage 2003 Herbig et al. 2003 A massive planet in FU Orionis discs • Periodic modulation of the line profiles: the signature of a massive planet? (Clarke & Armitage 2003) • Accretion onto the embedded planet • Hot spot in the disc at the instantaneous position of the planet • Observational evidence (Herbig et al. 2003)

  7. Influence of the planet on the outburst • Gap formation: rapid draining of the inner disc • Planet migration (Type II) : if the planet is massive enough, it is slower than the viscous evolution • Banking up of S upstream of the planet position • Triggered instability at planet position Rs Clarke & Syer 1996

  8. . m=nS=M/3p meq define the S-curve: analytical approximation from the Bell & Lin (1994) results Coupled planet-disc evolutionThe disc

  9. Analytic prediction from Ivanov et al. 1999 Coupled planet-disc evolution Planet migration Banking up

  10. Planet induced outbursts: the "reference" case . Min = 3 10-6 Mo/yr Ms = 15 MJupiter

  11. Details of the planet induced outburst • Trigger radius: Rtrig≈ 11 Ro • Mass accretion rate in the inner disc during the outburst: Mout≈ 2.1 10-4 Mo/yr • Peak luminosity ≈ 400 Lo • Outer propagation radius of the instability Rlim ≈ 50 Ro .

  12. Rise time: trise≈ 2yr Peak luminosity: 400 Lo Light curves

  13. Long term evolution • Radial migration of the planet significantly slowed down. • Residual migration causes Rtrig to decrease • Most outburst features determined by Rtrig • Subsequent outbursts have: • Smaller amplitude (by a factor 2, after 10 outbursts) • Shorter recurrence time (by a factor 3, after 10 outbursts) • Longer rise time

  14. Dependence on planet mass • As planet mass increases, outbursts are triggered at progressively larger radii

  15. Summary of results • Massive planet (with M ≈ 10-15 MJupiter) able to trigger FU Orionis outbursts at R≈ 10 Ro • Outbursts properties (amplitude, duration, rise time) depend on the location where the outburst is triggered • Fast rise time (1-2 yr) if Ms ≈ 10-15 MJupiter • Radial migration of the planet significantly slowed down by the occurence of the outbursts

  16. Remaining issues and fututre developments • Steadiness of FU Orionis: tdecay< 60-70 yr in our models. All thermal instability models suffer from this problem. • What happens to the planet during the outburst? Both dynamically and physically • Long term evolution and planet migration • Triggered outburst for lower feeding rates?

More Related