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ACRIM and ATLAS-1 FAUST and ATLAS-1

ACRIM and ATLAS-1 FAUST and ATLAS-1. Mike Lampton Space Science Lab UC Berkeley September 2012. Understanding the Sun http://acrim.com/Educational%20Material.htm. All life on Earth depends on sunlight The sun is a slightly variable star! (Why?!)

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ACRIM and ATLAS-1 FAUST and ATLAS-1

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  1. ACRIM and ATLAS-1FAUST and ATLAS-1 Mike Lampton Space Science Lab UC Berkeley September 2012

  2. Understanding the Sunhttp://acrim.com/Educational%20Material.htm • All life on Earth depends on sunlight • The sun is a slightly variable star! (Why?!) • Sunspot cycles; Maunder minimum; Little Ice Age... • What are all the other short and long term cycles? • Variations in the sun’s spectrum • Controls what altitudes on Earth sunlight is delivered • Crucial separate drivers to climate & climate change • SOLSPEC (aboard ATLAS; EURECA; ISS-Columbus); SORCE/SIM... • Variations in the sun’s total irradiance • ACRIM; SOLCON; SOHO/VIRGO; SORCE/TIM; • “Absolute”: need electrical & mechanical calibration but not thermal M. Lampton UCB SSL 2012

  3. What is going on? Tectonic drivers: continental plate motions ocean - land latitude coverage volcanism: SO2, sulfates, ash... Earth orbit (Milankovich) drivers Precession cycle 26000 years Elliptical orbit rotation 21000 year Obliquity period 41000 years Solar drivers: sunspot cycles & TSI variations in spectrum Anthropogenic influences Worldwide climate: a nonlinear chaotic system complex radiation budget Radiative cooling M. Lampton UCB SSL 2012

  4. Thermal Balance Method: can achieve absolute error <0.01% solar heat • Solar heating power = TSI ∙ Area • Electrical heating power = V∙I • At null, TSI = Δ V∙I/Area • Mechanical standard: aperture A • Electrical standards: V and I moveable shutter aperture area = A ΔT cone 1 cone 2 data out data out bias power supply power amplifier meter meter null signal isothermal enclosure M. Lampton UCB SSL 2012

  5. Also: short-term missions: cross calibration Spacelab 1 (1983) ATLAS 1 (1992) ATLAS 2 (1993): comparison SARR2 Spacelab ACRIM M. Lampton UCB SSL 2012

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  7. Solar Irradiance and Spectra are studied worldwide.... from “Measurement And Uncertainty Of The Long Term Total Solar Irradiance Trend,” Steven Dewitte, Dominique Crommelynck, Sabri Mekaoui and Alexandre Jouko, Royal Meteorological Institute of Belgium, (2004) M. Lampton UCB SSL 2012

  8. Transit of Venus 5 June 2012 This “transit method” for discovering planets has been in continuous use since 2009 with the KEPLER mission: so far 2200 planet detections made, and 77 confirmations. HINODE image of sun JAXA/NASA M. Lampton UCB SSL 2012

  9. Historical Proxies for TSI • Total Solar Irradiance goes back ~ 30 years • Sunspots: go back ~ 400 years • Rates of growth of tree rings ~ 1000 years • 14C and 10Be content of organic matter: yet further back http://en.wikipedia.org/wiki/Maunder_Minimum Great Frost of 1709 M. Lampton UCB SSL 2012

  10. Ultraviolet Astronomy and FAUST • Astronomy at visible wavelengths... • easily done at night through Earth’s atmosphere • shows stars & galaxies under usual “main sequence” evolutionary circumstances • Astronomy at ultraviolet wavelengths... • reveals fluxes & spectra of very hot (short-lived) stars • reveals properties of interstellar gas and dust • starbirth: massive, very hot short-lived stars; OB’s • star death: fuel exhaustion; WDs; • variable galaxies; AGNs, BL-Lacs, LINERS, QSOs.... • but of course requires spaceborne platforms. • Frequent access to space speeds technology. M. Lampton UCB SSL 2012

  11. UV Space Astronomyexcluding solar M. Lampton UCB SSL 2012

  12. What was FAUST? • Created by L.A.M. as a rocket-borne UV camera for studies of nearby galaxies and especially star formation • used a UV intensifier and a photographic film recording canister • Adapted by L.A.M. and UCB for Spacelab 1 (1983) • same UV intensifier and a photographic film recording canister • unfortunately SL1 β-angle did not permit dark nights • Remanifested on ATLAS-1 (1992) for an enlarged program • Motive: star formation in our Galaxy and in other galaxies • total scientific success; 21 papers and all objectives met • allowed us at UCB to develop a new kind of photon counting imager • Spacelab HRM permitted high rate digital photon downlink • legacy for future UV missions: photon counting imager technology M. Lampton UCB SSL 2012

  13. FAUST ATLAS-1 Mission Highlights • Overall: 4.4% of the night sky was covered • 19 deep fields, 4698 objects measured; fluxes & locations for all targets • 2239 of them are stars; others are galaxies, nebulae, or unidentified • Ten times more sensitive than previous UV catalogs • Bowyer, S., et al., ApJS v.96, 461 (1995) • eleven other papers on sources, maps, identifications • Observations of the diffuse UV sky • Cohen, M., et al., ApJ v.427 848 (1994) • Observations of terrestrial UV nightglow • Chakrabarti, S., et al., GRL v.20 535 (1993) • Observations of the STS UV environment • Lampton, M., et al., GRL v.20, 539 (1993) • FAUST sensor technology development • Lampton, M., et al., Proc SPIE 627, 383 (1986) M. Lampton UCB SSL 2012

  14. Andromeda galaxy at visible wavelengths ... and in the ultraviolet using GALEX M. Lampton UCB SSL 2012

  15. Hubble Space Telescope and its Upgrades Launch STS31 Apr1990 SM2 STS82 Feb1997 SM1 STS61 Dec1993 SM4 STS125 May2009 SM3b STS109 Mar2002 SM3a STS103 Dec1999 Photon counting Photon counting Photon counting M. Lampton UCB SSL 2012

  16. Photon-counting image sensor concept -- now flying on many missions M. Lampton UCB SSL 2012

  17. Future of Ultraviolet Astronomy • Astonishing developments in Cosmology • 1929: Hubble and the expanding universe • 1933: Zwicky and missing mass. (Now: not even baryonic mass!) • 1963: Penzias & Wilson: cosmic microwave background & hot Big Bang • 1990: COBE satellite and gradients in the CMB; seeds for growth • 1998: Perlmutter; Riess; accelerating universe. Dark energy! • Picture emerges: denser regions collapsed first, then outer regions followed • Star formation peaked at redshift ~ 2, and continues to this day. UV traces it. • Cosmology is now pressing hard on reconciling gravity, space, time.... • Beyond that: stars, planets, nebulae, SNe, ISM, IGM.... • Future UV space observatories? • ASTROSAT (India) • World Space Observatory WSO (Russia; ESA; Spain) • Space Ultraviolet Observatory SUVO (NASA) • ATLAST (NASA + ESA) M. Lampton UCB SSL 2012

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