Age Calibration from Coeval White Dwarfs in K2 and TESS

Conference presentation, 20 min. January 2018: Dwarf Stars and Clusters with K2, Boston, MA, USA.

Transcript

1. http://jjherm.es J.J. Hermes Hubble Fellow, UNC Chapel Hill Age Calibration from Coeval White Dwarfs in K2 and TESS
2. Star Trek writer James Blish put planet Vulcan in orbit around 40 Eri A
3. Star Trek writer James Blish put planet Vulcan in orbit around 40 Eri A The age of 40 Eri A is ~1.8 Gyr
4. 40 Eri, S. Smith Star Trek writer James Blish put planet Vulcan in orbit around 40 Eri A 40 Eri B: coeval white dwarf with total age ~1.8 Gyr I have evolved telepathy in less than 2 billion years… ~35 au ~400 au Bond, Bergeron & Bédard 2017
5. WD Teff /Mass à WD Cooling Age WD Initial-Final Mass Relation à Main-Sequence Mass/Age Total System Age(~30%) How Do We Get Coeval Ages from White Dwarfs? + = - Cooling ages come from WD evolution models - Calibrated by WDs in clusters with known turnoff ages WD Teff /log(g)
6. see also Cummings et al. 2016 How do we build an Mi /Mf relation? E.g.: 0.77(0.03) M¤ WD in NGC 2527(630 Myr) 185 Myr WD cooling age tprog = 441 Myr -> Mprog = 3.1 M¤ Raddi et al. 2016
7. Bond, Bergeron & Bédard 2017 0.573±0.018 M¤ 17,200±110 K WD Cooling Age: ~122 Myr + Cluster-Calibrated Initial-to-Final Mass Relation (Cummings et al. 2016): 1.8 M¤ Progenitor: ~1.7 Gyr MS age 40 Eri, S. Smith ~35 AU ~400 AU 40 Eri B Total Age ~1.8 Gyr
8. Age Calibration from Coeval White Dwarfs in K2 and TESS
9. Rebassa-Mansergas et al. sdss-wdms.org K2 Campaign 5
10. WD 15,070(2000) K logg = 8.69(0.326) 1.04(0.173) M¤ ~0.8 Gyr total age M3 0.38(0.07) M¤ Prot = 4.59 d
11. A handful of composite WD+dM in K2 with likely dM rotation periods - All M1−M3 - No radial-velocity variations in SDSS subspectra - Spatially unresolved (all >200 pc away) Jennifer van Saders 0.3 < M/M¤ < 0.4 −0.4 < [Z/H] < +0.4 Fast and slow initial rotation rates
12. Age Calibration from Coeval White Dwarfs in K2 and TESS
13. Talbot & Gänsicke 2018, in prep. G0 PMRA = -22.0(2.3) mas/yr PMDec = -16.0(2.4) mas/yr WD PMRA = -22.2(4.7) mas/yr PMDec = -24.7(4.7) mas/yr Distance: ~260 pc Projected Sep: >28000 au 16,280(180) K 0.61(0.02) M¤ 2.1 M¤ progenitor ~1.1 Gyr total age
14. 5.0 7.5 10.0 12.5 15.0 Primary T (mag) 0 1 2 3 4 5 6 7 8 9 N 12 14 16 18 20 WD secondary V (mag) 0 2 4 6 8 10 1 10 100 1000 Separation (arcsec) 0 2 4 6 8 10 12 N 1.0 10.0 Total Age (Gyr) 0 2 4 6 8 10 N JJH, Jennifer van Saders, Boris Gänsicke, Jeff Andrews, Alberto Rebassa-Mansergas, Steve Kawaler, Pier- Emmanuel Tremblay, Julio Chanamé, Marcel Agüeros, Jay Farihi, James Davenport, Chris Clemens TESS Coeval Degenerates Survey, Cycle 1 A-1 F-7 G-12 K-12 M-26
15. Oh et al. 2017 Andrews, Chanamé & Agüeros 2017 Gaia will revolutionize finding common proper-motion binaries
16. WD Teff /Mass à WD Cooling Age WD Initial-Final Mass Relation à Main-Sequence Mass/Age Total System Age How Do We Improve Coeval Ages from White Dwarfs? + = - Core C/O Ratio (where heat stored) - Envelope Masses (opacities, how fast heat escapes) - Improved MS Ages - More WDs in Clusters for IFMR - More Wide WD+WD Binaries WD Teff /log(g)
17. WD Teff /Mass à WD Cooling Age WD Initial-Final Mass Relation à Main-Sequence Mass/Age Total System Age (~10%) How Do We Improve Coeval Ages from White Dwarfs? - Core C/O Ratio (where heat stored) - Envelope Masses (opacities, how fast heat escapes) - Improved MS Ages - More WDs in Clusters for IFMR - More Wide WD+WD Binaries WD Teff /log(g) White Dwarf Asteroseismology with K2/TESS Gaia
18. Clusters are a party
19. Coeval Degerates: Clusters of Two Calibrate gyrochronology, age-activity, & age-flaring continuously out to 8-10 Gyr in the solar neighborhood Gaia will uncover orders more wide WD+MS binaries
20. A ‘typical’ white dwarf electron degenerate C/O core (r = 8500 km) non-degenerate He layer (260 km) non-degenerate H layer (30 km) [thermal reservoir] [insulating blanket]