Mapping of stellar pulsations in eclipsing binaries

[ericagol]

As with many exoplanet ideas, there is cross-fertilization with stellar astrophysics. The starry formalism could perhaps be used in mapping pulsations of stars in eclipsing binaries during eclipses:

http://adsabs.harvard.edu/abs/1974ApJ...190..637N http://cds.cern.ch/record/1010338/files/0701459.pdf http://iopscience.iop.org/article/10.1086/491666 https://academic.oup.com/mnras/article/416/3/1601/959788 http://adsabs.harvard.edu/abs/2005ASPC..333..221B

Of course there is also the application of measuring starspots:

http://adsabs.harvard.edu/abs/1997MNRAS.287..556C http://adsabs.harvard.edu/abs/1997MNRAS.287..567C

and doppler imaging:

http://adsabs.harvard.edu/abs/1987ApJ...321..496V

perhaps this could also be applied to polarimetric reconstruction of stars:

https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2966.2010.16715.x

[rodluger]

@RuthAngus @benjaminpope As it happens Eric Agol had already thought of this! See his post above with useful references for our project.

@ericagol Ruth, Ben, and I are thinking of tackling this problem. There are several directions we could head in. Ben suggested looking for eclipsing RR Lyrae stars, although there don't seem to be any confirmed ones so far. But there are delta Scutis and cepheids.

Ben also suggested heartbeat stars: EB mapping could constrain non-radial tidal distortions. We should also look at Alpha2 CVn stars, which have chemically peculiar spots. We could do time-resolved spectroscopy to get a spatial-wavelength map: pretty cool!

Below is the rest of Ben's email for reference:

Looks like it might be hard to get great data but certainly worth doing. A list of interesting kepler EBs here http://keplerebs.villanova.edu/papers

Mode identification in classical pulsators remains controversial so if you could find an EB transiting a pulsator and do this decomposition, it would be really neat if you could identify one or two modes with ironclad certainty.

V380 Cyg might be a good candidate to try - https://arxiv.org/abs/1205.0554 - and conveniently, I've extended the light curve to the full Kepler campaign with the smear method. The g modes are low amplitude though so maybe it won't work.

Mode identification in eclipsing heartbeat stars might be another thing to try.

[ericagol]

Here's another reference that Keaton Bell mentioned to me today of an eclipsing white dwarf system which this may be interesting to apply this to:

http://adsabs.harvard.edu/abs/2016ApJ...821L..32Z

-Eric

[rodluger]

@benjaminpope I need to read it in more detail, but the target in the paper @ericagol posted above seems perfect for this prroject. Just look at this thing:

[benjaminpope]

Gorgeous! I wonder - it looks like the pulsations are tidally induced, and so they're phase coherent with the eclipses. What does this mean for the eclipse mapping?

On Fri, Sep 28, 2018 at 9:33 AM Rodrigo Luger notifications@github.com wrote:

@benjaminpope https://github.com/benjaminpope I need to read it in more detail, but the target in the paper @ericagol https://github.com/ericagol posted above seems perfect for this prroject. Just look at this thing:

[image: image] https://user-images.githubusercontent.com/9323819/46211426-834c4f00-c301-11e8-91e5-05a0066f87bf.png

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/rodluger/starry/issues/61#issuecomment-425436896, or mute the thread https://github.com/notifications/unsubscribe-auth/AFvsFYKdy-0qP3_YxFOxT6ZeZMBu5u2Iks5ufiUYgaJpZM4UF5wX .

-- Dr Benjamin Pope NASA Sagan Fellow Center for Cosmology and Particle Physics New York University 726 Broadway New York, NY 10003

[rodluger]

Good eye! I don't know. We can still map stuff I'm sure. Plus, ingress/egress duration is a sizable fraction of the orbital period, so the distortion won't appear as a purely radial mode.

[ericagol]

Yeah, the one thing that worries me about this system is whether one could treat the stars as spheres, which is a requirement for starry.