BVR photometry of comets 63P/Wild 1 and C/2012 K1 (PANSTARRS)

Betzler, Alberto Silva; Sousa, O. F. de; Diepvens, A.; Bettio, T. M.

doi:10.1007/s10509-020-03814-5

Cited by 7 publications

(5 citation statements)

References 68 publications

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“…The Spearman correlation test shows that the correlation between the B‐R color and phase angle and heliocentric distance cannot be considered statistically significant ( ρ = 0.01364 and −0.06542). In the visible, this property has already been described for the same color for samples with many comets (Kolokolova et al 2004) and for comets 63P/Wild 1 and C/2012 K1 (PANSTARRS) (Betzler et al 2020). These results support the idea that there is no dependence on distance, as suggested by Jewitt and Meech (1988) using IR data.…”

Section: Resultsmentioning

confidence: 54%

“…The median values of the three distributions indicate that the coma is redder than the Sun (Figure 9). However, the slope was neutral (=0%/100 nm) or negative for 20% of the total measurements, a similar percentage to comets C/2012 K1 (PANSTARRS) (19%) and 63P/Wild 1 (15%) (Betzler et al 2020) in the same spectral region. This last condition is circumstantial only and must be tested with a large sample of B‐R slopes of comets.…”

Section: Resultsmentioning

confidence: 59%

“…The inclusion of the outburst before the perielion results in a poor fit of (Equation 2) to the data ( R 2 = 0.0467 × 0.8145) and an unusually bright absolute magnitude ( H 0 = 4.8). Betzler et al (2020) showed that the absolute magnitudes of comets C/2012 K1 and 63P/Wild 1 vary as a function of the photometric aperture radius. This dependence leads to visual magnitudes that are systematically lower than those measured with photoelectric photometers or CCDs, as found for 1P/Halley by Betzler and de Sousa (2020) and for C/2014 S2 (PANSTARRS) by (Betzler et al 2018).…”

Section: Resultsmentioning

confidence: 99%

“…A common procedure in comet photometry is to couple the aperture radius ρ (in arcseconds) to a constant optocentric distance in kilometers (e.g., 10,000 km). Betzler et al (2018), (2020), and Betzler and de Sousa (2020) have shown that the application of this procedure causes systematic errors in the magnitudes of comets 1P/Halley, 4P/Faye, 63P/Wild, C/2012 K1 (PANSTARRS), and C/2014 S2 (PANSTARRS). To avoid systematic errors in the data, we used a fixed photometric aperture radius of 10.8 arcsec to determine the V‐band apparent magnitudes and BVR color indices obtained with telescopes T1–T4.…”

Section: The Data and Their Reductionmentioning

confidence: 99%

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Photometric BVR observations of comet C/2012 J1 (Catalina) before and after perihelion

Betzler

Sousa

2023

Astron Nachr

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We analyzed the BVR photometry of comet C/2012 J1 (Catalina) taken between March 2013 and May 2014 with telescopes ranging from 0.20 to 2.0 m aperture in Australia, Europe, and the United States. We found an absolute magnitude in the R-band of H 0 = 7.2 ± 0.1 measured with a photometric aperture radius 𝜌 of 42.4 arcsec, corresponding to projected distances in the sky of 7.2 × 10 4 -1.5 × 10 5 km. Comet C/2012 J1 (Catalina) shows an asymmetric secular light curve, which is typical for comets. The nucleus has a minimum radius of 3.3 km admitting an albedo of 0.04. The inner coma exhibited radial pulsations before perihelion related to the dust rate proxy Af𝜌. The Af𝜌 parameter was inversely proportional to the photometric aperture radius 𝜌 because the angular diameter of the coma was small compared with the aperture radii used. The comet had three outbursts with brightness variations between 0.2 and 2.99 magnitudes per event. The median normalized reflectivity gradient S ′ is 4.4 with an amplitude of 22.9%/100 nm in the spectral range between 440 and 647 nm. The dispersion of the gradient S ′ means that 20% of the measurements are bluer than the solar color.

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Section: Resultsmentioning

confidence: 54%

Section: Resultsmentioning

confidence: 59%

Section: Resultsmentioning

confidence: 99%

Section: The Data and Their Reductionmentioning

confidence: 99%

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Photometric BVR observations of comet C/2012 J1 (Catalina) before and after perihelion

Betzler

Sousa

2023

Astron Nachr

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“…This result is redder than ours, and it matches our expectation for JFCs, suggesting that 64P underwent a bluing process between September and November in 2018. The deviations from the mean color of comets might be indicative of unusual phenomena presented by an active comet, or a change in grain size distribution and/or composition, as Betzler et al (2020) suggested. In particular, Ivanova et al (2017) pointed out that the color of magnesiumrich silicate is consistent with the blue color we observed.…”

Section: The Anomalous Colormentioning

confidence: 84%

Physical properties and mini-outburst of 64P/Swift-Gehrels

Shi

et al. 2022

A&A

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Aims. We present secular multiwavelength broadband photometry, spanning over 93 days, performed at the Yaoan High Precision Telescope on comet 64P/Swift-Gehrels in its 2018-2019 apparition. Our aim is to study its dust activity, coma properties, and the accidentally discovered mini-outburst. Methods. We used aperture photometry to measure the A f ρ value and correct the back-scattering effect based on phase angle. We deployed azimuthally averaged image enhancement methods to identify the coma morphology and the outburst. Secular color measurement was also conducted on the comet. Results. We identified a -0.5 mag mini-outburst around January 3, 2019, with coma morphology study showing an obvious dust jet feature strengthened during the outburst. The maximum A(0) f ρ value of 64P/Swift-Gehrels recorded is 313 cm at the top of the fitted curve and 334 cm at the outburst event. Both volatile-driven pressure mechanisms and nonvolatile-driven mechanisms could be the major explanation for the outburst. We obtain a mean color B − V = 0.68 ± 0.03 and V − R = 0.08 ± 0.01. The B − V color is similar to the mean value for Jupiter Family comets, but the V − R color turns out to be bluest among all the recorded short-period comets. The cause of this anomaly remains unknown.

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