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By Daniel Fischer, Germany
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Venus Express watching the planet's surface thanks to the VMC in the near IR: ESA PR, MPS PM [idw]. VEX ground-based support images easier to submit with a new interface: ESA PR. Long-delayed VEX papers finally to come out in late November? PSB.
Update # 306 of Friday, November 9, 2007
Dramatic comet outburst; still naked eye after 2+ weeks! / UHECRs traced to AGN / Chang'e in lunar orbit!

Surface brightness of growing coma down while total magnitude holds; gas tail exciting but faint

While Holmes' ever growing dust coma is now approaching the Moon in size, its surface brightness is way down, compared to late October, but the total brightness still holds between 2 and 3 mag (it'll be getting hard to nail it down, though). The most dramatic aspect of 17P in the 3rd week after its giant outburst is the unexpected beauty of the gas tail which is mainly a photographic phenomenon for experts, though. For the visual observer, Holmes is still dominated by the outer and inner dust comae: On 6 Nov. the comet looked in 11x70 binoculars like it had looked in a small telescope a week earlier. The telescope now reveals that the coma is kind of 'broken open' on one side: the same position angle where the inner dust cloud and the plasma tail point. The latter has a pretty unusual structure, due to probably not only our slant viewing angle but also the fact that most gas was released by the nucleus in a short time interval. Thus the pronounced detachment of the tail from the coma in recent days does not necessarily point to a classical disconnection event.

Posted on November 2, 2007

Faint tail photographed and seen; comet Holmes' outer coma now ½°, brighter one 13' in size

With its total brightness still stable at about 2.3 mag. (making the comet plainly visible to the naked eye even from cities), Holmes has still more in store: a faint, stubby plasma tail! It has already been photographed since late October (see also picture list in sidebar!) and now also been sighted visually: In the night Nov. 1/2, Alan Hale was "pretty sure I was seeing at least one of the tail streamers that are showing in Michael Jaeger's excellent images. I was seeing it toward approximate pa 150, extending about 30' from the comet's center (which makes it about 12' from the "edge" of the halo). Its edge was sharper along the eastern side, while the western side was more diffuse (extending, perhaps, into some of the other streamers). At the same time Hale "estimated the inner [bright dusty] coma to be 13' in diameter and the outer [gassy] coma as 36' in diameter. In the 41 cm scope the pseudo-nucleus is definitely still there but is distinctly fainter than it has been earlier." Meanwhile image processing is bringing out interesting structure in the bright cloud next to the false nucleus - which a Pic du Midi movie shows expanding, so these are not image processing artefacts!

Posted on October 31, 2007

One week into outburst, brightness holds as diameter grows

Comet 17P/Holmes continues to amaze: The diameter of the coma is now approaching 10 arc minutes while the total brightness remains steady at about 2.3 mag. (Some reports also mention a faint outer halo which - in contrast to the dusty bright coma - seems to consist only of gas.) The author has observed the comet on several occasions between Oct. 28 an 31, naked eye (it looks like a fuzzy star, next to Alpha and Delta Persei), binoculars (a large bright circular disk with a much brighter central structure) and 5.5 and 10 inch Dobsonians: The latter reveal that the outer disk is actually limb-brightened and that there are two inner structures, a sharp point of light in the center of the main disk and a bright cloud offset from the central spot. While these features can be spotted visually, despite the light of the nearby Moon, their visibility is much enhanced by employing a video camera with integrating capability. Comets are suited particularly well for this approach as e.g. the experience with SW 3 had shown, but Holmes is different: It is so bright that only moderate integration is needed (x8 to x16)! Thus one can use Dobsonians even at high magnification and still get perfect star images (no trailing), with the comet's unique coma moving gently through the field of view in real-time ...

Posted on October 28, 2007

Hovering at 2.3m, Holmes' coma "increased dramatically in size and complexity"

By early October 28, the coma diameter of outbursting comet Holmes had grown to 6...7 arc minutes, with lots of fine-scale detail visible in large telescopes, while the total brightness has been almost constant at about 2.3 mag since October 25. For the naked eye, the comet ceased to look completely stellar on October 26, now it's looking more and more like a comet. The rare outburst has also caught the attention of professional astronomers, of course: "I've been observing this comet since 25.5 Oct at mm-wavelengths with the 12-m telescope at Kitt Peak, with help of L.Paganini," reports Michal Drahus from the German MPS today: "Between 25.5 Oct and now the HCN intensity dropped down by nearly 10 times. I suppose that what we are observing right now are only some leftovers from the outburst which haven't photodissociated and haven't left our beam yet... In contrast, even if the nucleus activity is over, the dust cloud will be probably visible for a long time. We measure gas expansion velocity of 0.35 [later corrected to 0.5] km/s, so dust should be much slower, and surely size-dependent. BTW, don't expect spectacular tail. There is only very little CO in this comet, so no strong source of CO+ tail... The only chance is a dust tail."

Posted on October 24, 2007

Incredible comet eruption: from under 17th to 3rd magnitude in hours!

A most amazing eruption is occuring on comet 17P/Holmes which was at 17 mag. at best but on October 24 suddenly began to brighten like crazy: Now (afternoon UTC) it has already reached 3rd magnitude and is easily visible to the naked eye, as reports from Japan indicate: "Perseus does not look 'Perseus' familiar to us due to the bright stellar object now." The comet looks like a bright, yellow star, and only magnification reveals a fuzzy coma around the dusty core. Holmes was discovered in 1892 thanks to a similar outburst, and hope is that the further development will be similar now: the coma should expand over time but stay bright for a week or more. "Following the initial stages of the [1892] outburst, the comet's total magnitude faded only very slowly and it remained visible to the unaided eye for about 3 weeks," advises comet guru John Bortle: "During this interval the coma expanded dramatically (as might be expected), reaching 20'-30' in size before its outer regions began to drop below the sky background." Moreover, there was a second outburst "of almost equal amplitude to the first one, about 75 days following its 1892 November brightening. Thus, I would urge everyone to watch very carefully for a possible repeat of this secondary event about the turn of the year."
Basic facts (and a light curve) and Holmes news on Astronomie.de, Kometen.info, Astrotreff and Kometarium. Also Comet Mailing List (deluge of debate) and Aktuelle Kometen and WAA (w/finder charts).
Visual observation reports of Nov. 9, Nov. 8, Nov. 7, Nov. 6, Nov. 5 (plus a detailled report, another one, a nice drawing and a public viewing), Nov. 4 (plus a report), Nov. 3 (and a controversial detailled report), Nov. 2+3, Nov. 2 in the evening and morning, at 2:25 UTC and overnight, Nov. 1 at 20:24, 19:30 (detailled, w/drawings!), 19:12, 18:00, 17:15 and 3:30 UTC, Oct. 31 at 18:43 and 11:17, UTC, Oct. 30 at 20:38, 18:28, 10:48 and 0:45 UTC, Oct. 29 at 23:10 (drawings!), 17:02 and 1:45 UTC, Oct. 28 in the evening and at 23:00, 22:00, 19:55 and 11:02 UTC, Oct. 27 at 23:46, 20:24, 18:58, 17:46, 10-11 and 4:00 UTC, Oct. 26 at 6, morning, 4:15, 1:30-2, 1:50 and 0:50 UTC, Oct. 25 at 22:20, 14:25, 12:00, 5:15, 5:10, 4:10 (dito), 3:07, 2:40 and 1:00 UTC and Oct. 24 at 20:19, 19:12, 17:17, 15:07, 13:12 and 11:15 UTC.
Narrowband photometry of Oct. 25.0 and radio astronomical observations of Oct. 25-28.
Pictures of Nov. 8 (a really great one, plus one with high contrast and another one, also coma detail and more), Nov. 7 (many), Nov. 6, Nov. 5 (tail also with just 200 mm), Nov. 4 (with fine tail, with smaller optics and in "stereo"), Nov. 3 (another and another nice one), Nov. 2 (long tail, also here, plus an animation) and Nov. 1 (more, more and a wide view and another and another one, plus many different focal lengths).
Earlier pictures of Oct. 31 (tail! Here too w/cool processing and here, here here and esp. here as well; more, more, more, more, more, more, more and a wide view and another one), Oct. 30 (more, more, more, more, more), Oct. 29 (with tail!; more, more, more, more), Oct. 27-29, Oct. 28 (more, more, more, plus highly processed), Oct. 28 vs. 27, Oct. 27 (more, more and more hi-res plus wide field views from Brunei and Brazil), Oct. 26 (more, more, more and wide field), Oct. 25 (another and another hi-res and a wide field view and more), Oct. 24 (in color, another hi-res and a medium field view).
Galleries from SpaceWeather, Pic du Midi, FG Kometen, Rattei, Gährken, Voltmer, Roerig, Bennett, Kempen, Berry, van Duin, Pivato, Freestar, Guscott, TOC Obs., Cloudbait, Spindler, Hergenrother, Lessmann, Chia, Kugel, Lindberg, Quanzhi, Scarmato and Stw. Herne.
Analysis by Vollmann (Oct. 31) and Menke (Oct. 30), an earlier paper on the diameter of Holmes' nucleus and thoughts about image processing.
Plus the history of Holmes (more and what it meant for the first weeks), the problem of estimating the brightness and what Bortle (later, still later), Hoenig and Hergenrother think about the physics of the outburst.
Indiana Univ., RAS, Univ. of Montreal and CfA Press Releases (earlier), S@N and coverage of Nov. 9: APOD. Nov. 8: Cosmic Variance. Nov. 7: Cumbrian Sky. Nov. 6: TIME. Nov. 5: KometenBlog (referring to the CM), DailyPress, NwS, APOD. Nov. 4: AstroProf. Nov. 3: AP, APOD. Nov. 2: Ast. Oct. 30: BBC, Ast., SC, APOD, PSB, WDR, BdW. Oct. 29: SC, APOD, n.a.i. Oct. 28: BAB. Oct. 27: SpD. Oct. 26: S&T, SC, APOD, ST, BAB, Sp. Oct. 25: Skirmisher (referring to this CM), NEO News, AN, NwS, DPA [alt., alt], NZ, W, more in German. Oct. 24: Space Weather, Bad Astro Blog, AKM Forum and Heise Online (all referring to this CM), Ast., SC, UT, NAA-Liste.

8P/Tuttle now at 12 mag.

This comet should be nice around turn of the year - according to still rare visual observations on Nov. 3, Nov. 1 and Oct. 31 it is now around 12 mag. Plus pictures of Nov. 1 and Oct. 29.
C/2007 F (LONEOS) fades quickly, with only 7th mag. on Nov. 7: observation on Nov. 7, Nov. 6 and Nov. 5/6. But it has a nice tail: picture of Nov. 3.

Highest-energy cosmic rays linked to Active Galactic Nuclei

Ultra-high Energy Cosmic Rays (UHECR) do not reach Earth from random directions in the sky: Using the Pierre Auger Observatory in Argentina, the largest cosmic-ray observatory in the world, a team of scientists from 17 countries found that the sources of the highest-energy particles are not distributed uniformly across the sky. Instead, the Auger results link the origins of these mysterious particles to the locations of nearby galaxies that have active nuclei in their centers. While the observatory has recorded almost a million cosmic-ray showers during its ongoing constrution in Argentina, only the rare, highest-energy cosmic rays can be linked to their sources with sufficient precision. Auger scientists so far have recorded 81 cosmic rays with energy above 4 x 1019 electron volts, or 40 EeV. This is the largest number of cosmic rays with energy above 40 EeV recorded by any observatory. At these ultra-high energies, the uncertainty in the direction from which the cosmic ray arrived is only a few degrees, allowing scientists to determine the location of the particle's cosmic source. The Auger collaboration discovered that the 27 highest-energy events, with energy above 57 EeV, do not come equally from all directions. Comparing the clustering of these events with the known locations of 318 Active Galactic Nuclei, the collaboration found that most of these events correlated well with the locations of AGNs in some nearby galaxies, such as Centaurus A.
Auger Obs., U. Utah, Michigan Tech, Univ. Granada, U. Adelaide and U. Chicago Press Releases and coverage by PhW, NwS, BBC, SC, ST, BdW.

Dwarf galaxies need dark matter too

Stars in dwarf spheroidal galaxies behave in a way that suggests the galaxies are utterly dominated by dark matter: U Mich. PR.
Are "Fossil Groups" morphed from cannibalized galaxies? Gemini PR. Black holes launch powerful cosmic winds from their accretion disks: SC.

Chang'e in lunar orbit, already circular: a first for China

"China's first lunar probe, Chang'e-1, successfully completed its first braking at perilune and entered the moon's orbit" on November 5, reports Xinhua: "Chang'e-1, following the instructions of the Beijing Aerospace Control Center (BACC), started braking at 11:15 a.m. at a position around 300 km away from the moon and entered the moon's orbit at around 11:37 a.m. after completing the braking, according to the BACC. 'It turns the satellite into a real circumlunar one, marking a new milestone in China's aerospace history and also the first move of the country's deep space explorations,' said Sun Laiyan, deputy head of the Commission of Science Technology and Industry for National Defense." After the braking, the probe's speed was slowed down to 1948 km/s, leaving it on a 12-hour elliptical moon orbit, with a perilune of about 200 km and an apolune of about 8600 km. On November 7, the orbit was circularized. "The satellite entered the designed working orbit just in time and very accurately today," said Sun Jiadong, the chief designer of the project.

Posted on October 31st

Chinese spacecraft launched to the Moon!

For the first time the PR China is venturing into deep space: On October 24 Chang'e was launched on time into a parking orbit around the Earth, from which it departed as planned on Oct. 31; the Moon should be reached on November 5, and the first images can be expected in late November. Not only was the launch broadcast live on TV: the public could buy tickets to attend the launch in person! "The Chang'e-1 moon orbiter has entered into a 16-hour orbit at 205 km perigee and 50,930 km apogee, statistics from the Beijing Aerospace Control Center (BACC) shows," says the first report from Xinhua. According to China's long-term plans, the mission has two generic objectives, reports NASA SF: "technological and scientific. The engineering objectives of Change'-1 are the development and launch of China's first lunar exploration satellite; the preliminarily mastering of the basic technologies for lunar orbiting exploration; to initiate lunar scientific exploration for the first time; and to initially establish lunar exploration engineering system and to accumulate experiences for follow-on projects of lunar exploration. The scientific objectives of Chang'e-1 are to obtain three-dimensional images of the lunar surface, precisely ascertain the basic structures and physiognomy of the lunar surface, and to initially map out the lunar geology and structural elements to provide information for the follow-on soft landing" - and more.
Launch pictures, ESA Releases of Nov. 1 and Oct. 24 and coverage of Nov. 7: X (earlier, still earlier). Nov. 6: X, AFP. Nov. 5: X (earlier), SN, BBC, AFP, PSB, ST. Nov. 4: X. Nov. 2: X (earlier). Nov. 1: X. Oct. 31: X, MSNBC, Bulletin. Oct. 30: X. Oct. 29: X (more). Oct. 27: X. Oct. 25: X, Scotsman, WP, NYT, CSM. Oct. 24: X (earlier, still earlier, even earlier, still earlier), SN, PS, Rtr, AFP, NSF, R, CD, BBC (earlier), PSB, ST, W. Oct. 23: Kyodo, X, PSB. Oct. 22: X (earlier).

Kaguya in science orbit, sends first HD movies

Regular operations will start in December. JAXA Release of Nov. 7 and coverage of Nov. 8: LPOD. Nov. 7: PSB. Oct. 27: LPOD. Oct. 22: PSB.
Dawn in check-out, first test images received: DLR PM and Journal of Oct. 26. Vesta's chemistry: PSRD. MESSENGER in conjunction: Oct. 30 Status.
Analyzing solar wind samples from Genesis mission for neon and argon, two abundant noble gases: WUStL Record.

Mars Update

MSL landing site down-selection, instrument descopings revised. Stern statement and coverage of Nov. 9: PS (B). Nov. 8: PSB. Nov. 2: NwS. Oct. 29: PSB. Oct. 25: PSB. Oct. 24: PSB. Oct. 23: PSB. Mars Express ESA Release of Nov. 1, NASM PR of Nov. 1 and coverage of Nov. 8: SC. Nov. 2: ST, BdW. Nov. 1: NwS, MSNBC. MER images 101... 05, 04 and coverage of Nov. 8: NwS. Nov. 6: SC. Nov. 1: PS. Meteors on Mars - how to detect them: S&T. Phobos & Deimos conference: NwS, PSB.

Saturn Update

U Colorado PR of Oct. 24, pictures # 100... 80, 79, 97... 68, 67, 66, 65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54 and coverage of Nov. 9: BdW. Nov. 7: NwS. Oct. 31: PSB. Oct. 25: BdW. Oct. 24: SC. Oct. 22: PSB.

ISS etc. Update

Discovery is back after STS-120, having delivered Harmony to the ISS. NASA Releases of Nov. 9, Nov. 7, Nov. 1, Oct. 30 and Oct. 23, ESA Release of Oct. 23 and coverage of Nov. 9: SN, CBS2. Nov. 8: NYT (OpEd). Nov. 7: SR, SN, SC, BBc, ST, W. Nov. 6: SN (earlier), ST. Nov. 5: SN, SC, SpR, AB, ST. Nov. 4: SN, SC, WP, NYT. Nov. 3: SN (earlier, still earlier), BBC, SC, ST (other story), W. Nov. 2: AD, SC, ABC, ST. Nov. 1: SN (earlier), NYT, BBC, Tehran Times, ST. Oct. 31: SN, SC, BBC, ST (earlier), W. Oct. 30: SN, NYT, SC (other story). Oct. 29: SN, SpR. Oct. 28: SN, ST. Oct. 27: SN, SC, Oct. 26: SN, SC, ST (earlier). Oct. 25: SN (earlier), SC, ST. Oct. 24: SN (earlier), SC (earlier), NYT. Oct. 23: SN, G, NYT (OpEd), SC, ARRL, ST. Oct. 22: BBC, FT, G, SC (earlier), ST.

Fifth planet found around 55 Cnc

Other exoplanet systems with 4, 3 or 2 planets are also known - ours is probably not unusual: details, Berkeley, JPL, NSF and UCSC Releases, more material and coverage by WP, PBS, S&T, G, MSNBC, BBC, HonAdv, NwS, SC, Ec., PSB, MSNBC, ST, BdW, W.

More SuperWASP successes - three giant planets: G, SC. Hunting planets at Lick Obs.: Sta. Cruz Sentinel.

Stellar black hole with 24 to 33 solar masses claimed

Using two NASA satellites, astronomers have discovered a black hole that obliterates a record announced just two weeks ago and resides in the dward galaxy IC 10: CfA and NASA Press Releases, Harvard Gazette, S&T, SC, W. Black hole winds: RIT PR. Hundreds found: JPL Release, SC. What black holes are good for: WP. Shells of stars around quasar: HST PR.

Supernova caused by merging white dwarfs? There may be more than one way to make a Ia supernova: CfA Press Release, SC.

Computer simulations of star birth ask what the initial conditions must look like if a new-born star cluster is to survive for a long time: Uni Bonn PR. Role of B fields: SC. Betelgeuze's variations: S&T.

Solar telescope reaches 120,000 feet

A solar telescope recently rose to an altitude of 120,000 feet, borne by a balloon larger than a Boeing 747 jumbo jet - the test cleared the way for long-duration polar balloon flights beginning in 2009: UCAR PR, NwS, SC.

A long story about the Large Binocular Telescope from the BBC.

Proton returns to flight

A Russian Proton rocket launched three navigation satellites on Oct. 26 in the first flight for the booster since a failure less than two months earlier: SN, ST.

Russia launches third German radar satellite of the SAR-Lupe series: SN, ST.

ESA claims a space tether world record - contrary to earlier assessments (see last Update) the Foton tether unwound fully before the Fotino capsule was released: ESA Release.


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