Results from UVCS and LASCO Observation of the Sungrazing Comet C/2000 C6

Uzzo, M.; Raymond, J. C.; Biesecker, D. A.; Marsden, B. G.; Wood, Charlotte; Ko, YK; Wu, Rai

doi:10.1086/322473

Cited by 30 publications

(40 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Collisional excitation of H i Lyα is generally less important than photoexcitation at the densities and heliocentric distances considered here, even when Doppler dimming is strong. From an observational point of view, the collisional excitation can be discarded by considering that the H i Lyβ emission from this comet is negligible, as was found in previously observed sungrazers (Raymond et al 1998;Uzzo et al 2001). The ratio of Lyβ to Lyα is about 0.001 for radiative excitation and 0.16 for collisional excitation, so the nondetection of Lyβ implies that the collisional contribution to Lyα is small.…”

Section: Physical Processes and Ratesmentioning

confidence: 82%

“…They imply nucleus sizes on the order of 10 m (Raymond et al 1998;Uzzo et al 2001;Bemporad et al 2005) to hundreds of meters (McCauley et al 2013). Increases in the apparent size of the nucleus imply breakup, providing an estimate of the tensile strength of the nucleus (Uzzo et al 2001).…”

Section: Introductionmentioning

confidence: 99%

“…Increases in the apparent size of the nucleus imply breakup, providing an estimate of the tensile strength of the nucleus (Uzzo et al 2001). The timescale for fading of the Lyα brightness makes it possible to determine the coronal density without integration along a line of sight (Uzzo et al 2001). A persistent Lyα signature can be interpreted in terms of a refractory population of grains (Kimura et al 2002;Bemporad et al 2005).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Probing the Solar Wind Acceleration Region With the Sun-Grazing Comet C/2002 S2

Giordano¹,

Raymond²,

Lamy³

et al. 2014

ApJ

Self Cite

View full text Add to dashboard Cite

Comet C/2002 S2, a member of the Kreutz family of sungrazing comets, was discovered in white-light images of the Large Angle and Spectromeric Coronagraph Experiment coronagraph on the Solar and Heliospheric Observatory (SOHO) on 2002 September 18 and observed in H i Lyα emission by the SOHO Ultraviolet Coronagraph Spectrometer (UVCS) instrument at four different heights as it approached the Sun. The H i Lyα line profiles detected by UVCS are analyzed to determine the spectral parameters: line intensity, width, and Doppler shift with respect to the coronal background. Two-dimensional comet images of these parameters are reconstructed at the different heights. A novel aspect of the observations of this sungrazing comet data is that, whereas the emission from most of the tail is blueshifted, that along one edge of the tail is redshifted. We attribute these shifts to a combination of solar wind speed and interaction with the magnetic field. In order to use the comet to probe the density, temperature, and speed of the corona and solar wind through which it passes, as well as to determine the outgassing rate of the comet, we develop a Monte Carlo simulation of the H i Lyα emission of a comet moving through a coronal plasma. From the outgassing rate, we estimate a nucleus diameter of about 9 m. This rate steadily increases as the comet approaches the Sun, while the optical brightness decreases by more than a factor of 10 and suddenly recovers. This indicates that the optical brightness is determined by the lifetimes of the grains, sodium atoms, and molecules produced by the comet.

show abstract

Section: Physical Processes and Ratesmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Probing the Solar Wind Acceleration Region With the Sun-Grazing Comet C/2002 S2

Giordano¹,

Raymond²,

Lamy³

et al. 2014

ApJ

Self Cite

View full text Add to dashboard Cite

show abstract

“…If this happens in the coma, the geometry is simple and the propagation close to radial (a "pencil beam"). Raymond et al (1998) and Uzzo et al (2001) point out a different possibility. They observed bright sungrazers close to and in the breakup region in the Lyman-α line using UVCS on SOHO.…”

Section: Energetic Neutral Atomsmentioning

confidence: 99%

Are the sungrazing comets the inner source of pickup ions and energetic neutral atoms?

Bzowski¹,

Królikowska²

2005

A&A

View full text Add to dashboard Cite

show abstract

“…Over the past two decades, several comets have also been spectroscopically detected by the UltraViolet Coronagraph Spectrometer (UVCS; Kohl et al 1995) instrument onboard SOHO (Raymond et al 1998(Raymond et al , 2002Uzzo et al 2001;Povich et al 2003;Bemporad et al 2005Bemporad et al , 2007Ciaravella et al 2010;Giordano et al 2015). In this Letter, we report the water production rate at perihelion of a non-Kreutz comet observed by UVCS, comet C/1997 H2 (Stezelberger et al 1997), as determined from the H i Lyα intensity profile obtained when the comet was at a distance of ∼0.14 AU from the Sun.…”

Section: Introductionmentioning

confidence: 99%

Water production rate of comet C/1997 H2 (SOHO) near perihelion

Mancuso

2015

A&A

View full text Add to dashboard Cite

Comet C/1997 H2 is a non-Kreutz comet that was observed near perihelion at 0.137 AU on 1997 May 2 with the Ultraviolet Coronagraph Spectrometer (UVCS) aboard the Solar and Heliospheric Observatory (SOHO) satellite. The observed H i Lyman α radiance profile at 1215.67 Å, which was obtained during the crossing of the cometary coma through the UVCS slit positioned at 8.48 R , was least-squares fitted to a Haser model with hydrogen atom velocities of ∼20 km s −1 and ∼8 km s −1 (from photodissociation of H 2 O and OH, respectively). In order to obtain a better agreement between the observed H i Lyα radiance profile and the model, an additional population of low-velocity (∼4 km s −1 ) hydrogen atoms was required. This low-velocity component is attributed to thermalization of a substantial fraction (≈30%) of fast hydrogen atoms within the cometary collision zone. The hydrogen production rate of comet C/1997 H2 for the crossing near perihelion corresponds to a water production rate of Q H 2 O = 6.64 × 10 28 molecules per second.

show abstract

Results from UVCS and LASCO Observation of the Sungrazing Comet C/2000 C6

Cited by 30 publications

References 23 publications

Probing the Solar Wind Acceleration Region With the Sun-Grazing Comet C/2002 S2

Probing the Solar Wind Acceleration Region With the Sun-Grazing Comet C/2002 S2

Are the sungrazing comets the inner source of pickup ions and energetic neutral atoms?

Water production rate of comet C/1997 H2 (SOHO) near perihelion

Contact Info

Product

Resources

About