Cool Stars 19 Talk

Red Giants in Eclipsing Binaries Exploring Non-Oscillators and Testing Asteroseismic Scalings

Meredith L. Rawls New Mexico State University University of Washington/LSST (Fall 2016)

June 10, 2016 • Cool Stars 19

@merrdiff

Image: G Perez, IAC, SMMIn collaboration with P. Gaulme, J. McKeever, J. Jackiewicz, et al.

Meredith L. Rawls • @merrdiff

✦ Eclipsing binaries with light curves and radial velocities let us directly measure M, R

✦ Asteroseismology is a powerful tool to characterize lots of stars quickly, using light curves alone

✦ We can study oscillating stars in eclipsing binaries from two independent perspectives

✦ A set of well-characterized binaries lets us explore why some don’t oscillate when we think they should

How to measure stellar properties?


✦ Kepler red giant catalog: ~14,000✦ Kepler eclipsing binary catalog: 2,500+✦ After cross-correlating: 19✦ Most systems are SB2, but 4 are SB1✦ Most are oscillators, but 4 are not

Searching for red giants in eclipsing binary systems

Gaulme et al. 2013 & 2014


Δν

νmax

Power

Frequency ν

✦ Acoustic pressure modes✦ Buoyant gravity modes✦ Evolutionary state✦ Scaling relations

Characterizing a star: asteroseismology


Characterizing a star: binary modeling

9.30

9.35

9.40

9.45

9.50

Magnitude

ELC Model

−60

−40

−20

0

20

40

RadialVelocity(km

s−1)

0.0 0.2 0.4 0.6 0.8 1.0

−0.0040.0000.004

−202

9.259.309.359.409.459.50M

agnitude

0.20 0.21 0.22 0.23

−0.0040.0000.004

0.49 0.50 0.51 0.52

Orbital Phase (conjunction at φ = 0.5)

Secondary Primary

∆

∆

∆

✦ Double red giant KIC 9246715✦ Stars are nearly twins✦ Simultaneously fit radial

velocities and light curve

Rawls et al. 2016

Radialvelocities

Keplerlight curve

Eclipsezoom

KIC 9246715


Pipeline comparisons: Teff, [Fe/H], log g

Gaulme et al. submitted


Tides and magnetism affect oscillations

P = 20 de ~ 0non-oscillator

P = 207 de = 0.23oscillator

Rawls et al. in prep


Tides and magnetism affect oscillations

Obs

erve

d e

expect e ~ 0 expect e > 0

short P long P

Rawls et al. in prep

✦ Predicted change in eccentricity from stellar evolution modeling

✦ Non-oscillators have short P, circularized orbits, and spots


Asteroseismic scalings overestimate M and R

0.8 1 1.2 1.4 1.6 1.8 2 2.2

0.8

1

1.2

1.4

1.6

1.8

2

2.2

Dynamical mass [M⊙]

Ast

erose

ism

icm

ass

[M⊙

]

Seis

mic

mas

s (M

⊙)

Dynamic mass (M⊙)

16%

*

8 9 10 11 12 13 14

8

9

10

11

12

13

14

Dynamical radius [R⊙]

Ast

erose

ism

icra

diu

s[R

⊙]

Dynamic radius (R⊙)

Seis

mic

radi

us (R

⊙)

6%*

Gaulme et al. submitted


✦ Solar-like oscillations are damped by magnetism & tides, which occur together

✦ Scaling relations overestimate giant M, R✦ These stars are references for survey pipelines✦ Asteroseismic surveys underestimate ages

and exclude active stars and close binaries

Red giant binaries are powerful benchmarks for asteroseismology

Cool Stars 19 Talk

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Transcript of Cool Stars 19 Talk