Activity on Magnetic CV Secondaries:

Nature or Nurture?

Activity on Magnetic CV Secondaries:

Nature or Nurture?

Stella Kafka

Spitzer Science Center / Caltech

Stella Kafka

Spitzer Science Center / Caltech

Wild stars in the old west II - Tucson 2009

R.K. Honeycutt (IU), C. Tappert (UC), T. Ribeiro (UFSC), S. Howell (NOAO), D.W Hoard (SSC/Caltech)

Magnetic CVs - Secondary Star

Animation: A. Beardmore

Late K/M V

Survive common

envelope phase & nova

explosions

M-dot ~ 10-11-10-9 M¤/yr

P<7h

Magnetically active

Stellar Activity: our Sun

MDI, SOHO, ESA, NASA

TRACE Project, NASA Vacuum Tower Telescope, NSO, NOAO

AB Dor

Stellar activity in field stars

Wavelength (Å)

M3-inactive

Hα

M3-active

EV Lac – Flare

Strassmeier, K.

JD-2448400

Data: RoboScope (Honeycutt 1990-2005)

SS Cyg

BY Cam

V

Mag.

Consequences of activity

Disrupted magnetic

braking (eg Ritter 1985; Taam & Spruit 1989;

Hameury 1991)

Long-term lc modulations(eg Bianchini 1987, 1988; Warner 1988; Ak et al 2001)

Animation: A. Beardmore

Consequences of activity

Animation: A. Beardmore

Disrupted magnetic

braking (eg Ritter 1985; Taam & Spruit 1989;

Hameury 1991)

Long-term lc modulations(eg Bianchini 1987, 1988; Warner 1988; Ak et al 2001)

Dwarf nova outburst

periodic behavior (eg Meyer-Hofmeister, Vogt & Meyer 1996)

VY Scl low states(Livio & Pringle 1994; Kafka & Honeycutt 2005)

AM Her: 1990 - 2008

JD - 2448200

V M

ag.

Shakhovskoy et al. 1993Kafka et al. 2006, 2007, 2008 - data: RoboScope & AAVSO

AM Her: 1990 - 2008

V M

ag.

JD - 2448200

WIYN3.5m

KPNO 2mV

Mag

.

JD - 2448200.

MMT6.5m

WIYN3.5m

Kafka et al. 2006, 2007, 2008 - data: RoboScope & AAVSO

AM Her Spectrum

Wavelength (Å)

Kafka et al. 2008

F

(erg

s/cm

2/s

ec/

Å)*

10

-15

Wavelength (Å)

Sept 2006

Hα trailed spectrum

Hα doppler map

vx (km/sec)

vy (

km/s

ec)

Hα - satellites

Secondary’s side of CM

Same shape &

curvature

Visible for ½ phase

Resemble partial ring

around the secondary

Structure

Persistent

Magnetic Activity (“Prominences”)

Kafka et al. 2008

Wavelength (Å)

Sept 2006

Other systems*

*Also see poster #35 by Howell et al.Phase

RV

(km

/sec)

R

ela

tive

Inte

nsi

ty

ST LMi VV Pup

Phase

RV

(km

/sec)

F

(erg

s cm

-2 s

-1 Å

-1)

AM Her ST Lmi(Kafka et al.

2007)

VV Pup(Mason, E. et al.

2008)

EF Eri(Kafka et al. in prep)

Porb (h) 3.09 1.90 1.67 1.37

Donor star

M4-M5 M8 M8 L4??

B (MG) 13.5 11.5 32/55 12.6

Kafka et al. 2007 Mason, E. et al. 2008

Magnetic activity on CV donor stars: Nature or Nurture?

??Artwork: A. Beardmore

SDSS J204827.9+005008.9Low Accretion Rate Polar

(LARP)WD (0.6Msun) + M3

P~4h

Wavelength (Å)

counts

Kafka et al. 2009, in prep.

M-dot ~ 6*10-14Msun/year

(Schmidt et al. 2005)

WD (0.6Msun) + M3P~4h

Wavelength (Å) Wavelength (Å) Kafka et al. 2009, in prep.

counts

SDSS J204827.9+005008.9Low Accretion Rate Polar

(LARP)

AM Her vs J2048

vx (km/sec)

vy (

km/s

ec)

vx * 103(km/sec)

vy *

10

3(k

m/s

ec)

M-dot: 10-12Msun/year (low state) 6*10-14Msun/year

Magnetic activity on CV donor stars: Nature or Nurture?

?

Artwork: P. Marenfeld (NOAO/NSF)

?Artwork: A. Beardmore

Conclusions: Direct detection of (induced) magnetic structures on the donor star of magnetic CVs

Grounds for modeling

SDSS J2048AM Her

?