Sreejith Aickara Gopinathan for CUTE Team · Sreejith Aickara Gopinathan for CUTE Team Institut für Weltraumforschung Österreichische Akademie der Wissenschaften. INSTITUT FÜR

INSTITUT FÜR WELTRAUMFORSCHUNG

IWF.OEAW.AC.AT

CUTE CUBESAT MISSION N

Sreejith Aickara Gopinathan for CUTE TeamInstitut für Weltraumforschung

Österreichische Akademie der Wissenschaften


IWF.OEAW.AC.AT 2

CUTE TEAM

Colorado Ultraviolet Transit Experiment

Kevin France [PI], Brian T. Fleming [Project Scientist]

Science Team: Luca Fossati, Tommi Koskinen, Aline A. Vidotto, Keri Hoadley, Jean-Michel Desert, Matthew Beasley, Pascal Petit

Other team members: Nicholas Nell, Richard Kohnert, Kelsey Pool, Arika Egan, A. G. Sreejith


IWF.OEAW.AC.AT

PLANETARY ATMOSPHERIC ESCAPE

3

Escape observable only through UV observations, hence not possible from the ground


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GJ 436 B

4Lavie et al. 2017


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HD 209458 B

5Vidal-Madjar et al., 2013

Absorption signature : 8.8% ± 2.1%


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WASP-12B

6Fossati et al., 2010, Haswell et al., 2012


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CURRENT STATUS

7

More than 1000 planets with orbit < 10 days – only few have been observed in UV

Need of repeated observations

Need more planets to be observed

Time dependent signatures – require continuous observations

FUV observations are hard


IWF.OEAW.AC.AT

FUV

Absorption against chromospheric emission lines e.g. H I Lyα, O I, C II, Si III Faint stellar continuum Stellar variability

NUV

Absorption of high oscillator strength atomic features Brighter and more steady continuum Avoid stellar emission lines

FUV VS NUV

8A.Egan et al., 2018


IWF.OEAW.AC.AT

CURRENT STATUS UV MISSIONS

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UV observations Exoplanets in short-period orbits can provide valuable information regarding atmospheric escape

HST is the only UV spectroscopic eye

Needs—

Survey, continuous observation and monitoring capabilities – not possible with a shared facility like hubble.

Ideal for a CubeSat– Hence

WHY CUTE

10

the

The CUTE Solution


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MOTIVATION

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OBSERVE: Close orbiting exoplanets < 5 day orbital periods with transits lasting several hours

CREATE: Spectroscopic light curves Flux ~ (Rp(λ)/R*)2

DEDUCE: Atmospheric properties

Geometry

Composition

Massloss rates

BONUS: Detect/measure planetary magnetic field?


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ASTRONOMY WITH CUBESATS

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CUTE PAYLOAD

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Solar panels

Payload

S band transmitter

NUV telescope

Radiator panel

Heat strap

Instrument electronics

Spectrograph

Attitude control unit


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CUTE TELESCOPE

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Geometric clear area for a 20 x 8 cm

cassegrain: AT ~ 152 cm2

Geometric clear area for a 9cm

cassegrain: AT ~ 47 cm2

Performance relative to GALEX NUV Grism:Aeff,CUTE = 70% of GALEXRCUTE = 40x GALEX NUV

Angular Resolution: SimilarResolving Power ~ to HST-COS G230L

B. Fleming et al., 2018


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CUTE SPECTROGRAPH

16B. Fleming et al., 2018


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CUTE SPECTROGRAPH

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Render of CUTE telescope with a transparent primary mirror to display the mounting of the secondary and spectrograph enclosure.

A.Egan et al., 2018


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CUTE SPECTROGRAPH

18A.Egan et al., 2018


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CUTE SPACECRAFT

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Proprietary of Blue canyon technologies


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CUTE PERFOMANCE

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2550 2700 2850 3000 3150 3300Wavelength (Å)

Effective Area (cm2)Projected Grating EfficiencyDetector Quantum EfficiencyMgF2 + Al Reflectivity

0.0

0.2

0.4

0.6

0.8

1.0

Eff

icie

ncy

0

10

20

30

40

Eff

ecti

ve

Are

a (c

m2)

−1.5 −1.0 −0.5 0.0 0.5 1.0 1.5Angstroms

0.0

0.2

0.4

0.6

0.8

1.0

Rel

ativ

e In

ten

sity

Mg II2600 Å3150 Å1 Resol

B. Fleming et al., 2018


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CUTE DATA SIMULATOR

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KELT-7 CUTE field map and simulated imageA. G. Sreejith et al., 2018


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HD209458b transit light curve in a four resolution element (3.2 Å or 337 km/s) bin around the MgI 2852 Å resonance line. The light curve (black filled circles) [10 transits rebinning: 10 CUTE frames]. The red squares show the data-points and uncertainties presented by Vidal-Madjar et al., 2013 over a 50 km/s bin.

CUTE DATA SIMULATOR

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By accounting for the difference in considered wavelength range, the uncertainties oneach data point obtained from HST and expected for CUTE are about the same

A. G. Sreejith et al., 2018

HD209458b single transit light curve obtained integrating over a 100 Å continuum region (2884–2984 Å ) and re-binning over ten consecutive frames.


IWF.OEAW.AC.AT

Top-left: precision on the transit depth, in %, for a 5 minutes CUTE observation integrating in wavelength above 3000Å. Top-right: as top-left, but integrating in wavelength below 2750Å.Bottom-left: same as top-left, but integrating in wavelength around the MgII h&k resonance lines

(2790–2810Å). Bottom-right: same as top-left, but integrating in wavelength around the MgI resonance line (2850–2854Å). Each panel also shows the position of systems for which signatures of atmospheric escape have been observed in the past

CUTE DATA SIMULATOR

23A. G. Sreejith et al., 2018


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EFFECT OF JITTER

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Gaussian profiles given as input to the simulator (black) and obtained after a full simulation with (blue) and without (red) spacecraft jitter


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TEMPORAL COVERAGE

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CUTE is a 6U CubeSat NASA mission planed for launch in early 2020

– Mission dedicated to observe UV exoplanet transits to study atmospheric escape, composition, aerosols and planetary magnetic fields

– 4 years mission: 3 years to build and test , 1+ years to operate

Pave the way to close the gap in the UV exoplanet field after HST

CONCLUTIONS

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EXTRA

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Downlink: S-band 1 Mbps Daily Data: 0.7 Gb/day Uplink: UHF 19.2 kbps

Nominal mission: 10 transits per target, multi factor increase in observations

Each observation of 300 seconds

Preferred orbit : Sun-synchronous

3 5 transits observed per week in SSO

Extended mission could last up to 2 years, given orbital decay, spacecraft health, and funding

Downlink:Sband antenna patch oriented towards LASP Two 6 min. passes per dayGround stations in Boulder, CO and Fairbanks, AK


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EXTRA

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Documents

Sreejith Aickara Gopinathan for CUTE Team · Sreejith Aickara Gopinathan for CUTE Team Institut für Weltraumforschung Österreichische Akademie der Wissenschaften. INSTITUT FÜR