Do bipolar PNe really have more massive progenitors?

Central stars?Central stars?

Do bipolar PNe really have more massive progenitors?

Central stars?Central stars?

Eva Villaver (STScI/ESA)

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OutlineOutline

Central star massesMageLlanic Clouds

RESULTS in the GalaxyHints from the

progenitors:Galactic Scale HeightCHemical Enrichment

Possibilities?

HOW DO we determine masses?

HOW DO we determine masses?

MCS/M=0.5+(1.8 x10-5) L/L

How we weigh the stars in the LMC and SMCHow we weigh the stars in the LMC and SMC

+ Combined with Ground-based data (c,HeII 4686Å fluxes): Jacoby & Kaler (1993); Meatheringham et al. (1988); Meatheringham & Dopita (1991); Vassiliadis

et al. (1992); Boronson & Liebert (1989); Monk et al. (1988); Leisy & Dennefeld (1996); Dopita & Meatheringham (1991ab); Shaw et al (2004); Palen et al. (2004).

HST data: STIS broadband

imaging and WFPC2 (Stromgren y) (Shaw et al. 2001,2007

Stanghellini et al. 2002, 2003)

Results in the LMC:Results in the LMC:

<MCS> (7) = 0.63± 0.06 R

<MCS> (19) = 0.65± 0.09 E

<MCS> (9) = 0.64± 0.04 B

From: Villaver, Stanghellini & Shaw (2003) Villaver, Stanghellini & Shaw (2007)

Results in the GalaxyResults in the Galaxy

<MCS> = 0.62± 0.08 R

<MCS> = 0.62 ± 0.07 E

<MCS> = 0.60± 0.03 B

Derived from the Stanghellini et al. (2002) sample to an extinction limit of c < 1 Manchado et al. (2000)

No strong empirical evidence CEntral stars of Bipolar PNe Are more massive No strong empirical evidence CEntral stars of Bipolar PNe Are more massive

BIASES:Method? 4 B, 30 E, 10 R spectroscopySmall number statistics YES alwaysFainter faster? Yes if more massive....no

evidence From detection vr non-detection RATE in the LMC

Hotter central stars? No evidence in Stanghellini et al. (2002) or in the LMC

Galactic SCALE HeightGalactic SCALE Height

• Corradi & Schwarz (1995) (400 PNe) <z>=130 pc BIPOLAR <z>=320 pc ELLIPTICALS

• Manchado, Villaver, Stanghellini & Guerrero (2000) (255 PNe) <z> = 179 pc BIPOLARS <z> = 308 pc ELIPTICALS <z> = 753 pc ROUND

Galactic Kinematics of BipolarsGalactic Kinematics of Bipolars

Bipolar PNe from a young disk population Zuckermann & Gatley (1988), Corradi & Schwarz (1995).

<z> consistent with a MMS ~3 M

Chemical EnrichmentChemical Enrichment

N/O and He abundances are that of the type I PNe defined by Peimbert and Torres-Peimbert (1987).

He/H ≥ 0.125 and log(N/O) > − 0.3.

From Corradi & Schwarz (1995) <N/H> = 2.37 ELLIPTICALS = 4.37 BIPOLARS From Stanghellini, Villaver, Manchado & Guerrero

(2002) <N/H> = 1.71 ROUND = 1.51 ELLIPTICALS = 5.66 BIPOLARS

See also Kwitter and Henry (2001) Perinotto et al. (2004)

Hints from the chemistryHints from the chemistry

0.8-1.7 M Only isotopic

ratios modified

ConvectionDURING the AGB

1.4-3 MC and He abundances are increased 3rd dredge-upFORMATION OF C-STARS

3-8 MHBB N and He increaseLong period O-STARS

Herwig 00, Karakas 02, Pols 01, Strainero 97, Stancliffe 04

Other hints Bipolar & massive progenitors

Other hints Bipolar & massive progenitors

Garcia-Hernandez et al. (2007) have identified a sample of obscure massive O-rich stars in the Galaxy through the analysis of Li and Zr abundances HBB, higher N.

Stanghellini et al. (2007) Spitzer spectra of PNe in the LMC and SMC. C/O<1 BIPOLARS no PNe with C/O>1 is asymmetric.

Undermassive white dwarfs (0.47 M) in a high metallicity cluster (Kalirai et al. 2007).

How well do we know the initial-to-final mass relation?

How well do we know the initial-to-final mass relation?

Weidemann (2000) monotonic IFMR.

+Claver et al. (01) & Williams et al. (04) large scatter in the IFMR: A MS 3-4 M ends up anywhere between 0.65 and 0.8 M

Kalirai et al. (2005) added 12 WDs from NGC 2099.

From Kalirai et al. (2005)

SO.....?SO.....?

MASS-LOSS HIGHER ????O-stars

~O.6 M

MMS > 4 M

C-stars

Can Mass-Loss be a problem?Can Mass-Loss be a problem?

Dust-driven winds work well for C stars but run into problems to explain mass-loss for O-stars.

(Woitke 2006 Hofner & Andersen 07)

Summary:Summary:

NO strong empirical evidence of bipolar PNe to have more massive central stars (Villaver et al. 2003, 2007).

STRONG empirical evidence that bipolar have more massive progenitors.

Massive progenitors loose more massHOW? Common envelope? Undermassive WDs Mass-loss rates enhanced for the massive O-rich stars? We need further constrains for the IFMR.