Post common envelope binaries from SDSS:White dwarf/main sequence binaries from SEGUE

Ada Nebot Gómez-Morán

Tucson, 16th March 2009

The collaboration:Matthias Schreiber (UV)

Monica Zorotovic Fiebig (PUC Santiago) Robert Schwarz (AIP)Axel Schwope (AIP)

Boris Gänsicke (Warwick)Alberto Rebassa-Mansergas (UV)

John Southworth (Warwick)Pablo Rodriguez-Gil (IAC)

Evolution into close binaries

Common Envelope (CE)

Angular Momentum Loss by Magnetic Braking

(MB)CV

Post Common Envelope Binaries(PCEB)

Willems & Kolb 2004

WDMS sample

• Before SDSS: 30 PCEBs (Schreiber & Gänsicke, 2003)– Hot WD + Late type secondary– The old population of WDMS is missing

• In the SDSS: ~1300 new WDMS (Silvestri et al. 2006, Rebassa et al. 2007)

Lack of cold WD and early SpT

Silvestri et al 2006

N N

SpT peak @ M4 Teff Peak @ 2x104K

WDMS with SEGUE

Calculated colors cover •104K TWD 6104K •K0 SpT M6

4104 K3104 K2104 K1.5104 K

TWD

1104 K

SEGUE: ~10 Sloan fibers/plate pair 278 new WDMS (Schreiber et al. 2006, 2009 in prep.)

Success rate ~ 60%

Stellar parameters

Rebassa-Mansergas et al 2007, Scheiber et al 2009

Teff,log(g) dwd

SpT dsec

GALEX

SpT-R

Stellar parameters

Schreiber et al 2009 (in prep.)

Peak @104 K

Peak @ M3

Activity ?

Completeness, space density and scale height

Space density

~310-5-610-6 pc-3

h = 100-150 pc exp(-z/h)

Completeness

d (p

c)

cooling age (years)

|b|sp

ace

dens

ity (

10-4 p

c-3)

RVs from the SDSS subexposures

RV > 3 Identification of 44 PCEB

candidates

Fraction PCEB/WDMS ≥16%

Flu

x (1

0-17 e

rgs-1

cm2Å

-1

Wavelength (Å)

SDSSJ030138.24+050218.9

Nebot Gómez-Morán et al in prep.

Orbital Periods

Nebot Gómez-Morán et al in prep.

Outlook

• With SEGUE the old population has been identified • 44 new PCEB from the sub-exposures of the SDSS spectra

PCEB fraction > 16%• The ~2000 WDMS systems form the database to constrain

close binary evolution.

Thanks!

White dwarf effective temperature

White dwarf mass

Number of M stars

Silvestri et al. 2006

Spectra

Flu

x (1

0-17er

g cm

2 s

-1 Å

-1)

Wavelength (Å)

Space density

Ncand : Number of objects inside the criteriaNspec : Total number of spectra NWDMS: Number of WDMSNout : Number of WDMS outside the criteria

V : Volume