Frozen to death? Detection of comet Hale-Bopp at 30.7 AU

Szabó, Gy. M.; Sárneczky, K.; Kiss, L. L.

doi:10.1051/0004-6361/201116793

Cited by 19 publications

(14 citation statements)

References 26 publications

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“…5 we plot the total brightness estimates (both visual and CCD) of post-perihelion Hale-Bopp. The data were collected from the ICQ database and from Szabó et al (2008Szabó et al ( , 2011 and references therein. Previously published brightness estimates are plotted with open circles, the new post-perihelion measurements are denoted by solid dots.…”

Section: A 25 Magnitude Apparent Brightness Variation Inmentioning

confidence: 99%

Evidence for Fresh Frost Layer on the Bare Nucleus of Comet Hale-Bopp at 32 Au Distance

Szabó

Kiss

Pál

et al. 2012

ApJ

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Here we report that the activity of comet Hale-Bopp ceased between late 2007 and March, 2009, at about 28 AU distance from the Sun. At that time the comet resided at a distance from the Sun that exceeded the freeze-out distance of regular comets by an order of magnitude. A Herschel Space Observatory PACS scan was taken in mid-2010, in the already inactive state of the nucleus. The albedo has been found to be surprisingly large (8.1±0.9%), which exceeds the value known for any other comets. With re-reduction of archive HST images from 1995 and 1996, we confirm that the preperihelion albedo resembled that of an ordinary comet, and was smaller by a factor of two than the post-activity albedo. Our further observations with the Very Large Telescope (VLT) also confirmed that the albedo increased significantly by the end of the activity. We explain these observations by proposing gravitational redeposition of icy grains towards the end of the activity. This is plausible for such a massive body in a cold environment, where gas velocity is lowered to the range of the escape velocity. These observations also show that giant comets are not just the upscaled versions of the comets we know but can be affected by processes that are yet to be fully identified.

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Section: A 25 Magnitude Apparent Brightness Variation Inmentioning

confidence: 99%

Evidence for Fresh Frost Layer on the Bare Nucleus of Comet Hale-Bopp at 32 Au Distance

Szabó

Kiss

Pál

et al. 2012

ApJ

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“…Introducing this value in we obtain R = 13.2 km. Szabó, Sárneczky & Kiss (2011) have recently detected Hale–Bopp at 30.7 au to the Sun. From its observed magnitude and assuming a 4 per cent albedo, the authors derive a radius of 60–65 km if the nucleus were inactive.…”

Section: Introductionmentioning

confidence: 99%

Magnitude and size distribution of long-period comets in Earth-crossing or approaching orbits

Fernández

Sosa

2012

Monthly Notices of the Royal Astronomical Society

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We analyse the population of near‐Earth long‐period comets (LPCs; perihelion distances q < 1.3 au and orbital periods P > 103 yr). We have considered the sample of LPCs discovered during the period 1900–2009 and their estimated absolute total visual magnitudes H. For the period 1900–1970 we have relied upon historical estimates of absolute total magnitudes, while for the more recent period 1970–2009 we have made our own estimates of H based on Green’s photometric data base and IAU Circulars. We have also used historical records for the sample of brightest comets (H < 4.5) covering the period: 1500–1899, based mainly on the Vsekhsvyatskii, Hasegawa and Kronk catalogues. We find that the cumulative distribution of H can be represented by a three‐modal law of the form log10N< H=C+αH, where the C values are constants for the different legs, and α≃ 0.28 ± 0.10 for H < 4.0, α≃ 0.56 ± 0.10 for 4.0 ≤H < 5.8, and α≃ 0.20 ± 0.02 for 5.8 ≤H < 8.6. The large increase of the slope of the second leg of the H‐distribution might be at least partially attributed to splitting of comet nuclei, leading to the creation of two or more daughter comets. The cumulative H‐distribution tends to flatten for comets fainter than H≃ 8.6. LPCs fainter than H≃ 12 (or diameters D≲ 0.5 km) are extremely rare, despite several sky surveys of near‐Earth objects implemented during the last couple of decades, suggesting a minimum size for an LPC to remain active. We also find that about 30 per cent of all LPCs with q < 1.3 au are new (original bound energies 0 < Eor < 10−4 au−1), and that among the new comets about half come from the outer Oort cloud (energies 0 ≲Eor≲ 0.3 × 10−4 au−1), and the other half from the inner Oort cloud (energies 0.3 × 10−4≲Eor≲ 10−4 au−1).

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“…That is, sublimation of these ices will occur beyond these heliocentric distances, just to a much lesser degree than within them (Cowan & A'Hearn 1979). We note, however, that while it is possible that cometary activity could occur at such large heliocentric distances, few comets have been observed to exhibit such behavior Szabó et al 2008Szabó et al , 2011Kramer et al 2014).…”

Section: Introductionmentioning

confidence: 76%

The Perihelion Emission of Comet C/2010 L5 (WISE)

Kramer

Bauer

Fernández

et al. 2017

ApJ

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The only Halley-type comet discovered by the Wide-Field Infrared Survey Explorer (WISE), C/2010 L5 (WISE), was imaged three times by WISE, and it showed a significant dust tail during the second and third visits (2010 June and July, respectively). We present here an analysis of the data collected by WISE, putting estimates on the comet's size, dust production rate, gas production (CO+CO 2 ) rate, and active fraction. We also present a detailed description of a novel tail-fitting technique that allows the commonly used syndyne-synchrone models to be used analytically, thereby giving more robust results. We find that C/2010 L5ʼs dust tail was likely formed by strong emission, likely in the form of an outburst, occurring when the comet was within a few days of perihelion. Analyses of the June and July data independently agree on this result. The two separate epochs of dust tail analysis independently suggest a strong emission event close to perihelion. The average size of the dust particles in the dust tail increased between the epochs, suggesting that the dust was primarily released in a short period of time, and the smaller dust particles were quickly swept away by solar radiation pressure, leaving the larger particles behind. The difference in CO 2 and dust production rates measured in 2010 June and July is not consistent with "normal" steady-state gas production from a comet at these heliocentric distances, suggesting that much of the detected CO 2 and dust was produced in an episodic event. Together, these conclusions suggest that C/2010 L5 experienced a significant outburst event when the comet was close to perihelion.

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Frozen to death? Detection of comet Hale-Bopp at 30.7 AU

Cited by 19 publications

References 26 publications

Evidence for Fresh Frost Layer on the Bare Nucleus of Comet Hale-Bopp at 32 Au Distance

Evidence for Fresh Frost Layer on the Bare Nucleus of Comet Hale-Bopp at 32 Au Distance

Magnitude and size distribution of long-period comets in Earth-crossing or approaching orbits

The Perihelion Emission of Comet C/2010 L5 (WISE)

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