Redefining the Initial-Final Mass Relation*

1. Redefining the Initial Final Mass Relation
Jason Kalirai
(JHU APL)

2. Redefining the Initial Final Mass Relation
Jason Kalirai
(JHU APL)

3. Harvey Richer
Large Hubble Space Telescope Programs
(PI H. Richer)
Cycle Star Cluster Distance [Fe/H] Orbits
9 Messier 4 2.2 kpc -1.2 123
13 NGC 6397 2.3 kpc -2 126
17 47 Tuc 4.5 kpc -0.7 121
Bold Scientific Leadership

4. Harvey Richer
Advocate for Canada’s
Scientific Leadership
Champion and Mentor of
Early Career Scientists
Large Hubble Space Telescope Programs
(PI H. Richer)
Cycle Star Cluster Distance [Fe/H] Orbits
9 Messier 4 2.2 kpc -1.2 123
13 NGC 6397 2.3 kpc -2 126
17 47 Tuc 4.5 kpc -0.7 121
Bold Scientific Leadership
FRIENDSHIP

5. The Stellar Initial Mass Function and
its Dependency on Environment
Our Research Program
3 Key Ingredients to Bridge Stars and Galaxies
Kalirai et al. (2013)
High Precision
Color Magnitude Relations
Kalirai et al. (2012)
Kalirai et al. (2009; 2014)
Cummings et al. (2016; 2018)
Mass Loss and
Evolutionary Timescales

6. Why White Dwarfs?
Unique White Dwarf Characteristics
White dwarfs are the evolutionary end state for >95% of all stars
- Contain the imprinted signature of rapid RGB/AGB evolutionary processes
- Used to infer stellar mass loss rates
- Assess contribution to galactic mass budget
- Determine primordial mass functions for first generation populations
White dwarfs have no nuclear fuel and therefore cool predictably with time
- Serve as cosmic clocks to date ancient populations
- Used to infer early Milky Way archaeology
White dwarfs are supported by degenerate electron pressure
- Serve as natural condensed matter laboratories for extreme stellar structure studies
- Unique insights on stellar thresholds and pulsations through seismology
White dwarfs have (mostly) simple H atmospheres
- Spectroscopical determination of fundamental properties without knowing their distances
White dwarfs are among the faintest stars in the Universe
- Increased contrast to detect planets and measure the composition of planetary debris

7. Why White Dwarfs?
Unique White Dwarf Characteristics
White dwarfs are the evolutionary end state for >95% of all stars
- Contain the imprinted signature of rapid RGB/AGB evolutionary processes
- Used to infer stellar mass loss rates
- Assess contribution to galactic mass budget
- Determine primordial mass functions for first generation populations
White dwarfs have no nuclear fuel and therefore cool predictably with time
- Serve as cosmic clocks to date ancient populations
- Used to infer early Milky Way archaeology
White dwarfs are supported by degenerate electron pressure
- Serve as natural condensed matter laboratories for extreme stellar structure studies
- Unique insights on stellar thresholds and pulsations through seismology
White dwarfs have (mostly) simple H atmospheres
- Spectroscopical determination of fundamental properties without knowing their distances
White dwarfs are among the faintest stars in the Universe
- Increased contrast to detect planets and measure the composition of planetary debris

8. Log(g) = 7.0
P.-E. Tremblay & P. Bergeron, priv comm
The Tell Tale Signature of a White Dwarf

9. Log(g) = 7.0, 8.0
The Tell Tale Signature of a White Dwarf
P.-E. Tremblay & P. Bergeron, priv comm

10. Log(g) = 7.0, 8.0, 9.0
The Tell Tale Signature of a White Dwarf
P.-E. Tremblay & P. Bergeron, priv comm

11. The Trick
Simultaneously measure both the initial and final masses of stars
The Method - Cheating Past the Hard Stuff
The Initial-Final Mass Relation
(IFMR)

12. When we started…
The Initial-Final Mass Relation
(IFMR)

13. 3 Step Roadmap to Measure the IFMR
Photometric Survey
Uncover white dwarfs in
clusters and measure
cluster ages and
turnoff masses

14. 3 Step Roadmap to Measure the IFMR
Photometric Survey
Uncover white dwarfs in
clusters and measure
cluster ages and
turnoff masses
Spectroscopic Survey
Confirm remnants and
measure final (white dwarf)
properties (age, mass)

15. 3 Step Roadmap to Measure the IFMR
Photometric Survey
Uncover white dwarfs in
clusters and measure
cluster ages and
turnoff masses
Spectroscopic Survey
Confirm remnants and
measure final (white dwarf)
properties (age, mass)
Initial-Final Mass Relation
TCLUSTER - TWHITE DWARF = TPROGENITOR

16. Finding White Dwarfs in Star Clusters
Kalirai et al.
(2001a; 2001b; 2001c)
Kalirai et al. (2003)
Kalirai & Tosi (2004)
Kalirai et al. (2007)
Kalirai et al. (2008)
Kalirai et a. (2009)
M4

17. Bright White Dwarfs in the Globular Cluster M4
Kalirai et al. (2009; 2012)

18. Summary of Initial-Final Mass Relation
1.) Low mass stars like the Sun will lose 46% of their mass through stellar evolution
2.) Intermediate mass stars with MINITIAL = 2-3 MSUN will lose 70-75% of their mass
3.) Higher mass stars with MINITIAL = 5-6 MSUN will lose 80% of their mass
4.) Scatter in the relation is mostly due to observational errors
The Initial-Final Mass Relation
Weidemann (1977, 1987, 2000)
Reimers & Koester (1980’s)
Claver et al. (2001)
Dobbie et al. (2004, 2006)
Williams et al. (2004, 2007)
Liebert et al. (2005)
Kalirai et al. (2005a, 2005b)
Kalirai et al. (2005a, 2005b)
Kalirai et al. (2007, 2008, 2009)
Cummings et al. (2015)
Cummings et al. (2016a; 2016b)
Cummings et al. (2018a; 2018b)
1.26 MSUN

19. The Critical Mass b/w White Dwarfs and Supernovae
An Important Threshold in Astrophysics
Sets the number of core-collapse supernovae occurring in the Universe
Sets the level of energetic feedback in galaxies
Sets the formation rate of neutron stars (especially ones with low-velocity kicks)
Sets the nucleosynthetic yields and chemical enrichment from higher mass stars
Shapes the metallicity, star formation rate, and morphology of galaxies
Methods
Difficult to constrain theoretically due to unconstrained physical effects
- mass loss, overshooting, binary interactions, rotationally induced mixing
- end product could be a massive electron-degenerate white dwarf or an electron capture SNe
Difficult to constraint observationally due to the IMF and short evolutionary times
Indirect methods
- Fit stellar models to red supergiants in pre-images of SNe (e.g., Smartt 2009)
- Measure the SFH of a galaxy in the vicinity of a supernovae (e.g., Williams et al. 2018)
Results indicate MCRIT = 7 to <9.5 MSUN

20. The Initial-Final Mass Relation
Properties of Planetary Nebulae
(Ciardullo 2010)
Characterize Exoplanet Hosts
(Kilic, Gould, & Koester 2009)
Measure SN Rates, Evolution, and Progenitors
(Pritchet et al. 2008;
Greggio 2010; Kistler et al. 2011)
Constrain Star Formation Scenarios
(Leitner & Kravtsov 2011)
Study Disk Formation in LCDM
(Leitner & Kravtsov 2011)
Calculate Stellar IMF
(Lockmann, Baumgardt, &
Kroupa 2010)

21. Thank you, and Happy Birthday!