Lynx: Revealing the Invisible

Universe

Presented by Scott J. Wolk

(CfA)

Lynx - Revealing the Invisible Universe

Scott J. Wolk

Next Generation X-ray Observatory Capability trade space: • 0.1”-0.5” PSF (Chandra ~ 1.0”) • 2-5 m2 range (Chandra ~ 0.25m2) • FOV ~ 20’x20’ • µcalorimeter, CCD camera & dispersive gratings planned • All detectors are photon counting • Imaging spectroscopy ~1eV (Chandra ~50 eV) • Dispersive spectroscopy R > 3000 • ~2030 Launch • 5 year mission, 20+ years consumables

Scott J. Wolk

Schematic of Grazing Incidence, X-ray Mirrors

Scott J. Wolk

Chandra Observatory Description

Scott J. Wolk

Venus

Mars

Jupiter

Comets

Aurora Scattering

Charge Exchange

Some of the currently known sources of X-rays in the Solar System. The complete list incl‘s the Sun, Planets, Comets, Moons, the Io Flux Torus, and the Heliosphere itself. [See excellent review by Bhardwaj, Lisse, et al. 2007 and ESS 2008]

Saturn

Rings

Disk Disk

Solar System X-rays: Probes of Scattering & Solar Wind Charge Exchange

SWCX: Interaction between the Gravitationally Unbound Neutral Atmospheres of Comets and the Solar Wind

(Cravens 2000)

10 km Nucleus

D/Linear S4 2000 Chandra ACIS-S

0.3 – 0.8 keV

Solar Wind Charge Exchange (SWCXE) is the Dominant Ionization Process for Outflowing Cometary Gases Scott J. Wolk

Scott J. Wolk

Observing Comets

Three competing emission features: 1. C and N emission below 500 eV 2. O VII emission at 565 eV 3. O VIII emission at 654 eV

C+N

~ O

VII

O V

III /

O V

II fl

ux in

crea

ses

low abundance of highly charged oxygen cold wind high abundance of highly charged oxygen hot wind

H

E

F

G

C

A

B

D

H

E

F

G

C

A

B

D

Chandra spectra of comets:

O VIII / O VII

C+N

/ O

VII

flux ratios of all observed comets:

C+N

≪ O

VII

hot, fast, disturbed

cold, fast

warm, slow

Bodewits et al. 2007 Scott J. Wolk

Scott J. Wolk

Scott J. Wolk

Scott J. Wolk

Scott J. Wolk

Planetary Observation 101

Lynx Issues Observing Solar System Objects

Solar avoidance

Moving targets Complicated by the spacecraft orbit

Optically bright Optical signal on the detectors (CCD or µcal) Bias burn in False and shifted X-rays

Hard to track Often near other planets

Soft X-ray sources

Dispersive spectroscopy is hard on extended objects

Scott J. Wolk

Lynx Issues Observing Solar System Objects

Avoidances Sun avoidance - cannot be overridden - viewing is restricted to angles larger

than 46.4o from the center of the Sun. This restriction makes about 15% of the sky inaccessible on any given date, but no part of the sky is ever inaccessible for more than 3 months. There is also an anti-Sun avoidence of 10o

No Mercury and limited Venus observations.

Also limits Comets and inner asteroids.

Moon avoidance - viewing is restricted to angles larger than 6o from the limb of the Moon. This restriction makes less than 1% of the sky inaccessible at any time.

Bright Earth avoidance - viewing is restricted to angles larger than 10o from the limb of the bright Earth. This restriction makes less than 5% of the sky inaccessible at any time. Both avoidance can be waived, but at the price of a reduced-accuracy aspect

solution.

Chandra has observed the Earth and the Moon.

Thermal issues can limit the amount of time we can point in one direction to ~16 hours in some directions.

Scott J. Wolk

Lynx Issues Observing Solar System Objects

Moving targets Complicated

by the spacecraft orbit

But we use photon counting detectors and image reconstruction

Scott J. Wolk

Encke – Feb 2017

Lynx Issues Observing Solar System Objects

Moving targets Complicated

by the spacecraft orbit

But we use photon counting detectors and image reconstruction

Scott J. Wolk

Venus – Jan 2017

Lynx Issues Observing Solar System Objects

Optically bright Hard to track Often near other

planets Optical signal on

the detectors (CCD or µcal) Bias burn in False and shifted

X-rays

Scott J. Wolk Guide Camera FOV for Venus 2017

Scott J. Wolk

Optical Sensitivity

Optical blocking on detectors is achieved with a polyimide coated on both sides with a thin layer of aluminum.

For Chandra ACIS: ACIS-I Al/Polyimide/Al

1200Å 2000Å 400Å ACIS-S

Al/Polyimide/Al 1000Å 2000Å 300Å

CXC

Optical Sensitivity

ACIS-I -Mars

Shorter exposures

LETG - Venus

Stellar Temperature BI Chip in S array FI Chip in I array(K) (V-Magnitude) (V-Magnitude)

4000 8.1 2.875000 7.93 2.446500 7.73 1.79

10000 7.66 1.1720000 7.6 0.97

Scott J. Wolk

Optical Sensitivity Need to understand The event island What light leak really does 5x5 (very faint mode)

Try Changing the thresholds

Lynx Issues Observing Solar System Objects

Dispersive spectroscopy on extended objects is difficult

Scott J. Wolk

Science landscape in the late 2020s and beyond. . .

TESS, JWST, PLATO, WFIRST, Lucy, Psyche,

Europa?

time domain information on the stars themselves reveals rotation periods,

existence of flares, fundamental stellar parameters by way of asteroseismology

Scott J. Wolk

Nominal Lynx X-ray Spectrum of a K7V

Scott J. Wolk

Snios et al. 2015

Scott J. Wolk

Charge Exchange & Fluorescence with Lynx

Scott J. Wolk