Angular correlation of the stellar scintillation for large telescopes

Kornilov, V.

doi:10.1111/j.1365-2966.2012.21511.x

Cited by 10 publications

(15 citation statements)

References 33 publications

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“…the scintillation temporal power spectrum is filtered so that only low-frequency components, f < πD/V ⊥ affect the scintillation power). The scintillation weighting function with an exposure time, t, larger than the crossing time of the speckles is then multiplied by the corresponding wind shear filter function A s = D/πtV ⊥ q (Kornilov 2012a), and, …”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Atmospheric scintillation in astronomical photometry

Osborn¹,

Föhring²,

Dhillon³

et al. 2015

Mon. Not. R. Astron. Soc.

105

118

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Section: Discussionmentioning

confidence: 99%

“…Scintillation noise on large telescope could be overestimated by an order of magnitude (Kornilov 2012a). This suggests that extremely large telescopes will be even more of a valuable facility for high-precision photometry than previously thought.…”

Section: S C I N T I L L At I O N O N L a R G E A N D E X T R E M E Lmentioning

confidence: 99%

Atmospheric scintillation in astronomical photometry

Osborn¹,

Föhring²,

Dhillon³

et al. 2015

Mon. Not. R. Astron. Soc.

105

118

View full text Add to dashboard Cite

show abstract

“…Additionally, it has been suggested by Osborn et al (2015) that the median value of scintillation is a factor of 1.5 higher than suggested by Equation 5. In the case of differential photometry, the strength of scintillation depends on the number of uncorrelated reference stars n E (Kornilov 2012). The degree of correlation depends on the angular separations of the stars from each other (Kornilov 2012), where 20" is generally the radius within which they are correlated.…”

Section: Scintillationmentioning

confidence: 99%

“…In the case of differential photometry, the strength of scintillation depends on the number of uncorrelated reference stars n E (Kornilov 2012). The degree of correlation depends on the angular separations of the stars from each other (Kornilov 2012), where 20" is generally the radius within which they are correlated. Combining these two terms, and assuming our target and reference stars are uncorrelated, we have the following equation for the scintillation for differential photometry,…”

Section: Scintillationmentioning

confidence: 99%

Toward Space-like Photometric Precision from the Ground with Beam-shaping Diffusers

Stefánsson

Mahadevan

Hebb

et al. 2017

ApJ

122

134

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We demonstrate a path to hitherto unachievable differential photometric precisions from the ground, both in the optical and near-infrared (NIR), using custom-fabricated beam-shaping diffusers produced using specialized nanofabrication techniques. Such diffusers mold the focal plane image of a star into a broad and stable top-hat shape, minimizing photometric errors due to non-uniform pixel response, atmospheric seeing effects, imperfect guiding, and telescope-induced variable aberrations seen in defocusing. This PSF reshaping significantly increases the achievable dynamic range of our observations, increasing our observing efficiency and thus better averages over scintillation. Diffusers work in both collimated and converging beams. We present diffuser-assisted optical observations demonstrating -+ 62 16 26 ppm precision in 30minute bins on a nearby bright star 16 Cygni A (V = 5.95) using the ARC 3.5 m telescope-within a factor of ∼2 of Keplerʼs photometric precision on the same star. We also show a transit of WASP-85-Ab (V = 11.2) and TRES-3b (V = 12.4), where the residuals bin down to -+ 180 41 66 ppm in 30minute bins for WASP-85-Ab-a factor of ∼4 of the precision achieved by the K2 mission on this targetand to 101 ppm for TRES-3b. In the NIR, where diffusers may provide even more significant improvements over the current state of the art, our preliminary tests demonstrated -+ 3664 ppm precision for a K S =10.8 star on the 200 inchHale Telescope. These photometric precisions match or surpass the expected photometric precisions of TESS for the same magnitude range. This technology is inexpensive, scalable, easily adaptable, and can have an important and immediate impact on the observations of transits and secondary eclipses of exoplanets.

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“…Following the suggestion by Osborn et al (2015), we note that we have multiplied this constant factor by 1.5 from the 0.09 cm 2/3 s 1/2 value originally presented in Young (1967) and Dravins et al (1998), to better reflect the median value of scintillation noise. Finally, the 1 + 1/n E reference star term is derived in Kornilov (2012), and describes the number of uncorrelated reference stars n E . For our observations, we assumed that all our reference stars were uncorrelated.…”

Section: Ground-based Light Curve Analysismentioning

confidence: 99%

Diffuser-assisted Photometric Follow-up Observations of the Neptune-sized Planets K2-28b and K2-100b

Stefánsson

Mahadevan

et al. 2018

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We present precision transit observations of the Neptune-sized planets K2-28b and K2-100b, using the Engineered Diffuser on the ARCTIC imager on the ARC 3.5m Telescope at Apache Point Observatory. K2-28b is a R p = 2.56R ⊕ mini-Neptune transiting a bright (J=11.7) metal-rich M4 dwarf, offering compelling prospects for future atmospheric characterization. K2-100b is a R p = 3.45R ⊕ Neptune in the Praesepe Cluster and is one of few planets known in a cluster transiting a host star bright enough (V = 10.5) for precision radial velocity observations. Using the precision photometric capabilities of the diffuser/ARCTIC system, allows us to achieve a precision of 105 +87 −37 ppm, and 38 +21 −11 ppm in 30 minute bins for K2-28b, and K2-100b, respectively. Our jointfits to the K2 and ground-based light-curves give an order of magnitude improvement in the orbital ephemeris for both planets, yielding a timing precision of 2 min in the JWST era. Although we show that the currently available broad-band measurements of K2-28b's radius are currently too imprecise to place useful constraints on K2-28b's atmosphere, we demonstrate that JWST/NIRISS will be able to discern between a cloudy/clear atmosphere in a modest number of transit observations. Our light-curve of K2-100b marks the first transit follow-up observation of this challenging-to-observe transit, where we obtain a transit depth of 819 ± 50 ppm in the SDSS i band. We conclude that diffuser-assisted photometry can play an important role in the TESS era to perform timely and precise follow-up of the expected bounty of TESS planet candidates.

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Angular correlation of the stellar scintillation for large telescopes

Cited by 10 publications

References 33 publications

Atmospheric scintillation in astronomical photometry

Atmospheric scintillation in astronomical photometry

Toward Space-like Photometric Precision from the Ground with Beam-shaping Diffusers

Diffuser-assisted Photometric Follow-up Observations of the Neptune-sized Planets K2-28b and K2-100b

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