Of serendipitous discoveries Boris Gänsicke
1917: Van Maanen s star Ca H/K Carnegie Institution for Science Farihi 2016, NewAR 71, 9 Van Maanen 1917, PASP 29, 258 1920, Cont. Mt. Wilson Obs. 182
The 3 rd closest white dwarf Fe Ca H/K Mg Ca d=4.4pc Carnegie Institution for Science Van Maanen 1917, PASP 29, 258 1920, Cont. Mt. Wilson Obs. 182
White dwarfs 101 Rwd 0.01R R Mwd 0.65 M g~10 6 ms -2 g=9.8ms -2
White dwarfs are chemically stratified Pure H or He atmosphere Rwd 0.01R R Mwd 0.65 M g~10 6 ms -2 g=9.8ms -2 C/O core Althaus et al. 2010, A&A Rev 18, 471
The 3 rd closest white dwarf Fe Ca H/K Mg Ca d=4.4pc Carnegie Institution for Science Van Maanen 1917, PASP 29, 258 1920, Cont. Mt. Wilson Obs. 182 External pollution, but where do the metals come from?
1987: G29-38, brown dwarf or dust? Zuckerman & Becklin 1987, Nature 330, 138
1987: G29-38, brown dwarf or dust? metal pollution Koester et al. 1997, A&A 320, L57
1987: G29-38, brown dwarf or dust? Zuckerman & Becklin 1987, Nature 330, 138
Jura 2003, ApJL 584, 91 The standard model Asteroids are scattered by unseen planets towards the white dwarfs Debes & Sigurdsson 2002, ApJ 572, 556
Off-topic: accretion discs in close WD binaries SDSS1035+0558 Balmer lines Horne & Marsh, 1986, MNRAS 218, 761 Littlefair et al. 2006, Science 314, 1578
2006: A typical white dwarf(?) H Gänsicke et al. 2006, Science 314, 1908
2006: A typical white dwarf - Not MgII FeII H CaII Gänsicke et al. 2006, Science 314, 1908
2006: A gaseous metallic debris disc MgII FeII Horne & Marsh (1986, MNRAS 218, 761) CaII H Gänsicke et al. 2006, Science 314, 1908
Jura et al. 2008, AJ 135, 1785
Wilson et al. 2014, MNRAS 445, 1878 Transient Ca II emission
2003 Indirect imaging of debris discs around white dwarfs 0.2R time 2.0R 2014 Manser et al. 2016, MNRAS 455, 4467
Chemical signature rules out accretion from the interstellar medium Jura 2006, ApJ 653, 613
Debris bulk abundances of exo-asteroids Zuckerman et al. 2007, ApJ 672, 871
Measuring bulk compositions in the solar system Meteor crater, Arizona
Measuring bulk compositions in the solar system Meteor crater, Arizona Jura & Young 2014, ARE&PS 42, 45
Detailed abundance studies O, Mg, Si, and Fe are the major constituents of the debris (and also make up ~93% of the Earth), variations similar to solar system Zuckerman et al. 2011, ApJ 739, 101 Melis et al. 2011, ApJ 732, 90 Klein et al. 2011, ApJ 741, 64 Gänsicke et al. 2012, MNRAS 424, 333 Jura et al. 2015, ApJ 799, 109 Xu et al. 2014, ApJ 783, 79 Jura & Young, 2014, ARE&PS 42, 1 Wilson et al. 2016, MNRAS 459, 3282
Detailed abundance studies O, Mg, Si, and Fe are the major constituents of the debris (and also make up ~93% of the Earth), variations similar to solar system Carbon-depleted, similar to bulk Earth rocky carbon depleted Zuckerman et al. 2011, ApJ 739, 101 Melis et al. 2011, ApJ 732, 90 Klein et al. 2011, ApJ 741, 64 Gänsicke et al. 2012, MNRAS 424, 333 Jura et al. 2015, ApJ 799, 109 Xu et al. 2014, ApJ 783, 79 Jura & Young, 2014, ARE&PS 42, 1 Wilson et al. 2016, MNRAS 459, 3282
Detailed abundance studies O, Mg, Si, and Fe are the major constituents of the debris (and also make up ~93% of the Earth), variations similar to solar system Carbon-depleted, similar to bulk Earth rocky Refractory litophiles Ca/Al very similar to solar system bodies same Al/Ca as in SS carbon depleted Zuckerman et al. 2011, ApJ 739, 101 Melis et al. 2011, ApJ 732, 90 Klein et al. 2011, ApJ 741, 64 Gänsicke et al. 2012, MNRAS 424, 333 Jura et al. 2015, ApJ 799, 109 Xu et al. 2014, ApJ 783, 79 Jura & Young, 2014, ARE&PS 42, 1 Wilson et al. 2016, MNRAS 459, 3282
Detailed abundance studies O, Mg, Si, and Fe are the major constituents of the debris (and also make up ~93% of the Earth), variations similar to solar system Carbon-depleted, similar to bulk Earth rocky Refractory litophiles Ca/Al very similar to solar system bodies Strong evidence for differentiation (Fe, S, Cr overabundance) iron-rich carbon depleted same Al/Ca as in SS Zuckerman et al. 2011, ApJ 739, 101 Melis et al. 2011, ApJ 732, 90 Klein et al. 2011, ApJ 741, 64 Gänsicke et al. 2012, MNRAS 424, 333 Jura et al. 2015, ApJ 799, 109 Xu et al. 2014, ApJ 783, 79 Jura & Young, 2014, ARE&PS 42, 1 Wilson et al. 2016, MNRAS 459, 3282
Mesosiderite-like exo-asteroids Mesosiderite Vaca Muerta origin from a ~ 200-400 km differentiated asteroid (Scott et al. 2001, M&PS 36, 869)
What about water? Jura et al. 2009, ApJ 699, 1473 Jura & Xu 2010, AJ 140, 1129 Jura & Xu 2012, AJ 143, 6
2011:!?!? Koester et al. 2011, A&A 530, A114
Cool white dwarfs: planetary archaeology Ca Mg Na Teff=5500K Cooling age ~ 3Gyr! Ca Koester et al. 2011, A&A 530, A114
~230 cool WDs Rich variety Of abundances Fe-rich Hollands et al. in prep Ca/Na-rich
2015: The first detection of debris transits Vanderburg et al. 2015, Nature 526, 546 metals dust
Large occulters ~3min duration R cloud 2-4R wd Average extinction 10% dm/dt ~ 10 11 g/s Gänsicke et al. 2016, ApJ 818, L7
Large occulters Outburst on 67P/Churyumov Gerasimenko observed by ROSETTA ~3min duration R cloud 2-4R wd Average extinction 10% dm/dt ~ 10 11 g/s Gänsicke et al. 2016, ApJ 818, L7
N-body tidal disruption setup Veras et al. 2016, MNRAS submitted
Homogenous, ρ = 2.6 g/cm 3 Differentiated, ρ = 3.5 g/cm 3 Total disruption within a few days Veras et al. 2016, MNRAS submitted Stable for >90 days, Intermittent mantle disruption
Differentiated, ρ = 3.5 g/cm 3, eccentricity = 0.0
Differentiated, ρ = 3.5 g/cm 3, eccentricity = 0.1 Veras et al. 2016, MNRAS submitted
They provide insight into the formation, physical properties, and evolution of exoplanets that is very complementary to main sequence systems
Mike Jura has been a continuous source of inspiration, and has been always a few steps ahead. He will be dearly missed.