Proxima Centauri b is not a transiting exoplanet

Abstract We report Spitzer Space Telescope observations during predicted transits of the exoplanet Proxima Centauri b. As the nearest terrestrial habitable-zone planet we will ever discover, any potential transit of Proxima b would place strong constraints on its radius, bulk density, and atmosphere. Subsequent transmission spectroscopy and secondary-eclipse measurements could then probe the atmospheric chemistry, physical processes, and orbit, including a search for biosignatures. However, our photometric results rule out planetary transits at the 200 ppm level at 4.5 $\mu$m, yielding a 3σ upper radius limit of 0.4 R⊕ (Earth radii). Previous claims of possible transits from optical ground- and space-based photometry were likely correlated noise in the data from Proxima Centauri’s frequent flaring. Our study indicates dramatically reduced stellar activity at near-to-mid infrared wavelengths, compared to the optical. Proxima b is an ideal target for space-based infrared telescopes, if their instruments can be configured to handle Proxima’s brightness.

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Assessment of the accuracy of scaling methods for radiance simulations at far and mid infrared wavelengths

Journal of Quantitative Spectroscopy and Radiative Transfer ◽

10.1016/j.jqsrt.2021.107739 ◽

2021 ◽

pp. 107739

Author(s):

Michele Martinazzo ◽

Davide Magurno ◽

William Cossich ◽

Carmine Serio ◽

Guido Masiello ◽

...

Keyword(s):

Mid Infrared ◽

Scaling Methods ◽

Infrared Wavelengths

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First detection of ozone in the mid-infrared at Mars: implications for methane detection

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038125 ◽

2020 ◽

Vol 639 ◽

pp. A141 ◽

Cited By ~ 3

Author(s):

K. S. Olsen ◽

F. Lefèvre ◽

F. Montmessin ◽

A. Trokhimovskiy ◽

L. Baggio ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Polar Vortex ◽

Trace Gas ◽

Spectral Signature ◽

Infrared Range ◽

Mid Infrared ◽

Northern Latitudes ◽

Ultraviolet Range ◽

Vibration Rotation ◽

Methane Detection

Aims. The ExoMars Trace Gas Orbiter was sent to Mars in March 2016 to search for trace gases diagnostic of active geological or biogenic processes. Methods. We report the first observation of the spectral features of Martian ozone (O3) in the mid-infrared range using the Atmospheric Chemistry Suite Mid-InfaRed (MIR) channel, a cross-dispersion spectrometer operating in solar occultation mode with the finest spectral resolution of any remote sensing mission to Mars. Results. Observations of ozone were made at high northern latitudes (>65°N) prior to the onset of the 2018 global dust storm (Ls = 163–193°). During this fast transition phase between summer and winter ozone distribution, the O3 volume mixing ratio observed is 100–200 ppbv near 20 km. These amounts are consistent with past observations made at the edge of the southern polar vortex in the ultraviolet range. The observed spectral signature of ozone at 3000–3060 cm−1 directly overlaps with the spectral range of the methane (CH4) ν3 vibration-rotation band, and it, along with a newly discovered CO2 band in the same region, may interfere with measurements of methane abundance.

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Kerr nonlinearity and multi-photon absorption in germanium at mid-infrared wavelengths

Applied Physics Letters ◽

10.1063/1.4990590 ◽

2017 ◽

Vol 111 (9) ◽

pp. 091902 ◽

Cited By ~ 9

Author(s):

B.-U. Sohn ◽

C. Monmeyran ◽

L. C. Kimerling ◽

A. M. Agarwal ◽

D. T. H. Tan

Keyword(s):

Kerr Nonlinearity ◽

Photon Absorption ◽

Mid Infrared ◽

Infrared Wavelengths

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The DECam minute cadence survey – II. 49 variables but no planetary transits of a white dwarf

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz398 ◽

2019 ◽

Vol 490 (1) ◽

pp. 1066-1075 ◽

Cited By ~ 2

Author(s):

Kyra Dame ◽

Claudia Belardi ◽

Mukremin Kilic ◽

Armin Rest ◽

A Gianninas ◽

...

Keyword(s):

White Dwarf ◽

White Dwarfs ◽

Point Sources ◽

Habitable Zone ◽

Significant Evidence ◽

Rr Lyrae ◽

M Dwarf ◽

Rule Out ◽

Planetary Transits

Abstract We present minute cadence photometry of 31 732 point sources observed in one 3 $\rm deg^{2}$ DECam pointing centred at RA = 09:03:02 and Dec. = −04:35:00 over eight consecutive half-nights. We use these data to search for eclipse-like events consistent with a planetary transit of a white dwarf and other sources of stellar variability within the field. We do not find any significant evidence for minute-long transits around our targets, hence we rule out planetary transits around ∼370 white dwarfs that should be present in this field. Additionally, we identify 49 variables, including 40 new systems. These include 23 detached or contact stellar binaries, one eclipsing white dwarf + M dwarf binary, 16 δ Scuti, three RR Lyrae, and two ZZ Ceti pulsators. Results from the remaining two fields in our survey will allow us to place more stringent constraints on the frequency of planets orbiting white dwarfs in the habitable zone.

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The Cepheid Period‐Luminosity Relation at Mid‐Infrared Wavelengths. I. First‐Epoch LMC Data

The Astrophysical Journal ◽

10.1086/586701 ◽

2008 ◽

Vol 679 (1) ◽

pp. 71-75 ◽

Cited By ~ 35

Author(s):

Wendy L. Freedman ◽

Barry F. Madore ◽

Jane Rigby ◽

S. E. Persson ◽

Laura Sturch

Keyword(s):

Mid Infrared ◽

Infrared Wavelengths

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Dust size and spatial distributions in debris discs: predictions for exozodiacal dust dragged in from an exo-Kuiper belt

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2029 ◽

2020 ◽

Vol 497 (1) ◽

pp. 1143-1165 ◽

Cited By ~ 1

Author(s):

Jessica K Rigley ◽

Mark C Wyatt

Keyword(s):

Kuiper Belt ◽

Spectral Energy ◽

Habitable Zone ◽

Energy Distributions ◽

Mid Infrared ◽

Nearby Stars ◽

Computationally Expensive ◽

Free Parameters ◽

Grain Properties ◽

Size Distribution Of Particles

ABSTRACT The spectral energy distributions of some nearby stars show mid-infrared (IR) excesses from warm habitable zone dust, known as exozodiacal dust. This dust may originate in collisions in a planetesimal belt before being dragged inwards. This paper presents an analytical model for the size distribution of particles at different radial locations in such a scenario, considering evolution due to destructive collisions and Poynting–Robertson (P–R) drag. Results from more accurate but computationally expensive numerical simulations of this process are used to validate the model and fit its free parameters. The model predicts 11 μm excesses (R11) for discs with a range of dust masses and planetesimal belt radii using realistic grain properties. We show that P–R drag should produce exozodiacal dust levels detectable with the Large Binocular Telescope Interferometer (LBTI) ($R_{11} \gt 0.1{{\ \rm per\ cent}}$) in systems with known outer belts; non-detection may indicate dust depletion, e.g. by an intervening planet. We also find that LBTI could detect exozodiacal dust dragged in from a belt too faint to detect at far-IR wavelengths, with fractional luminosity f ∼ 10−7 and radius ∼10–80 au. Application to systems observed with LBTI shows that P–R drag can likely explain most (5/9) of the exozodiacal dust detections in systems with known outer belts; two systems (β Uma and η Corvi) with bright exozodi may be due to exocomets. We suggest that the three systems with exozodiacal dust detections but no known belt may have cold planetesimal belts too faint to be detectable in the far-IR. Even systems without outer belt detections could have exozodiacal dust levels $R_{11} \gt 0.04{{\ \rm per\ cent}}$ which are problematic for exo-Earth imaging.

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