1. SORCERESS: the right instrument for SOAR?
Need workhorse instruments for LSST.
Need a unique capability to survive 2020.
The narrow FOV and excellent image quality are perfect for an EPRV instrument.
Debra Fischer
Colby Jurgenson: optical designer of EXPRES
Tyler McCracken: control software, laser frequency comb
Andy Szymkowiak: software, electronics, +
Dave Sawyer: system engineering
Fernando Santoro and Gary Muller: mechanical engineers
Jessi Cisewski: stats prof – new methods
(Eric Ford, Xavier Dumusque, Jeff Valenti,
SAMSII postdocs: David Stenning and Dave Jones,
yale stats grad students)

2. If we reach high enough precision, we are guaranteed of success
If we reach high enough precision, we are guaranteed of success. Small rocky planets orbit almost every star.
How many NASA missions now have an exoplanet focus?
Masses are critical currency for increasing value of transits (TESS) and exoplanet masses are critical for interpreting spectra (JWST).

3. Advantages: Designed / built EXPRES for the 4.3-m DCT in Flagstaff.
Proposing to ~replicate for SOAR (with one change: split blue / red cameras)
Advantages:
Heritage of EXPRES and the years of experience that went into this spectrograph.
Essentially build to print – fabrication drawings complete
Fold in experience with EXPRES to improve SORCERESS
Will have data in hand by end of 2017, demonstrating performance.
We provide a tested software pipeline:
Scheduling
Extraction of spectra
Wavelength calibration
Statistical techniques for distinguishing photospheric velocities
Doppler analysis
Well understood cost
Well known timeline
If this is the science you want, SORCERESS is the right instrument.
EPRV error budget: 17 cm/s – will beat HARPS precision, but by how much?
Depends on ability to disentangle photospheric velocities – never been done before.

4. Science drivers: ExoEarths at HZ distances
Killer app: alpha Cen AB (Starshot Breakthrough), though ESPRESSO may get there first (commissioning this year)
Masses for transiting planets
Masses for Gaia planets
Spectral analysis that requires extraordinary fidelity and resolution (isotopes? Zeeman splitting?)
Where ESPRESSO ”wins:” faint stars.
Where HARPS ”wins:” has the time baseline and precision for Super-Earth and Neptunes, but problems with aliases
Where SORCERESS ”wins:” lowest amplitudes (smallest, most ubiquitous planets)
- highest resolution
- highest cadence - critical for multi-planet
- flexible scheduling - don’t underestimate the importance!

5. Why such high spectral resolution?
Because we’re not just trying to measure Doppler shifts anymore.

6. We are trying to disentangle stellar photospheric velocities from orbital velocities. Any instrument that does not do this is doomed to 1 m/s precision at best.

7. Resolution and S/N critical for disentangling stellar jitter.
Last 20 years: try to decorrelate photospheric velocities (line bisectors, Ca II HK, H-alpha, Ca IRT)
Next decade: go back to the spectrum. PCA of those 400,000 pixels shows that photospheric velocities imprinted differently.
Resolution and S/N critical for disentangling stellar jitter.
Davis et al 2017
(responding to referee)

8. Unique specifications – driven by need for extreme fidelity and need to disentangle photospheric velocities.
Vacuum enclosure, thermal stabilization, all invar bench and mounts
Laser frequency comb – few cm/s calibration precision from 400 – 700 nm
R=150,000, super-Nyquist sampling, 380nm to 1 micron
Octagonal fiber, pupil slicing, rectangular fiber (invert near/far field) with fiber agitation
Flat fielding! 2-d flat fielding with extended fiber. LED+Qtz source with inverse spectral response as the instrument.
Science spectrum
Flat field
SIM LFC spectrum

9. Unique specifications – driven by need for extreme fidelity and need to disentangle photospheric velocities.
Vacuum enclosure, thermal stabilization, all invar bench and mounts
Laser frequency comb – few cm/s calibration precision from 400 – 700 nm
R=150,000, super-Nyquist sampling, 380nm to 1 micron
Octagonal fiber, pupil slicing, rectangular fiber (invert near/far field) with fiber agitation
Flat fielding! 2-d flat fielding with extended fiber. LED+Qtz source with inverse spectral response as the instrument.
Camera optimized to be insensitive to changes in pupil illumination, uniform PSF, focus control; Mangin transfer mirror (corrects cylindrical aberration of white pupil design)
Wavelength-weighted flux corrections for barycentric corrections
STA CCD, new hi-res photolithography w/o stitching errors and higher QE (one more “9”) than e2v, 9-micron pixel size, 10k x 10k, measure sub-pixel positions using interferometry at JPL / Mike Shao
Statistical techniques for removing: photospheric velocities and telluric contamination
Nightly cadence – option of a couple hours per night is a game-changer.

10. Front end module: ADC, fast t/t (600 Hz for 100 Hz correction), innovative fiber mount for octagonal fiber, invar frame.
Calibration box: ThAr, LED-Qtz => extended flat fiber, LFC

11. Cost: Time: 18 months Funds in place Aug 2018
FEM $591,000
Spectrograph: $3,592,000
LFC $750,000
Site devel $250,000
Time: 18 months
Funds in place Aug 2018
SORCERESS delivered Dec 2019
Really is “SOAR2020” instrument.

12. Place order for large optics, grating, detectors

13. SORCERESS Throughput (sky not included – factor of 2??)

14. SORCERESS Work Breakdown – high level