Forthcoming 2007/2008 Mars

Mars in 2007/2008. I

CMO #325 (25 November 2006)

Masatsugu MINAMI, Masami MURAKAMI and Akinori NISHITA

Japanese here

00 The planet Mars in 2007 will be closest to the Earth on 19 December 2007 at 00h GMT, and at opposition on 24 December 2007 at 20h GMT and hence we should call the present case the 2007/2008 apparition. Here we are first concerned with the possible observational points in 2007.

01 The maximal angular diameter δ is predicted to be 15.9 arcsecs and so smaller than in 2005, while in 2007 the Martian season after λ=345Ls (around 11 November) is observable in more favourable condition than in 2005, that is, the apparent diameter δ is larger than in 2005. In particular in 2007 the season around the northern spring equinox (λ=360Ls) can be observable in preferable conditions. At the season λ=350Ls, the tilt of the north pole is still toward the Earth and reads φ=7N, and so the north polar hood is well observable. The vernal equinox will attain on 9 December with φ=4N. At the end of the year, the season reaches λ=010Ls when the Baum plateau of the npc begins (snow line is at Φ=58N). The tilt of the north pole will be away for a while until the end of February 2008, but the perimeter of the npc will remain stable if the Baum plateau is valid (or if not disturbed by dusts).

02 Around the time when the planet is at opposition, the planet will stay in Gemini, and so shines high up seen from the Northern Hemisphere (the altitude at the maximal time will read 70 or more from Japan), but quite low from the Southern Hemisphere.

03 Earlier the angular diameter δ reaches 5 arcsecs in mid-April 2007 when the season will read λ=220Ls. Since the tilt of the south pole is deeply toward us, we can watch the thawing of the spc. However in April the planet stays low since it is still in Aquarius. The planet will come back to the Equator at the end of May when δ=5.7".

04 So roughly speaking, Mars in 2007 will show us the seasons from λ=220Ls to 010Ls in which the size of the spc will decrease, the orographic cloud can be observed, the activity of the nph is well watched and so on. At the beginning we should be careful if the southern dust storms may occur, and at the end of the year we may well catch the npc when it comes out from the nph.

05 More concretely, we should be careful about the shape of the spc since its centre will deviate from pole toward Ω=030W from May. The spc will become a residual small cap around from the beginning of September. At the same time the central latitude will shift from south to north, and so it will become difficult to check the spc. Note however we need to watch how the spr since the south polar hood is given rise to.

06 On the other hand, the npr and nph become easier to watch from September. Already the Dawes Slit of the nph over M Acidalium may be visible (on 1 September 2007, λ=306Ls). In 2005 one of us (Mn) observed it at around λ=310Ls from Mt Hamilton, and he also saw it in 1990 at around λ=320Ls, and DAWES himself detected it around λ=340Ls, and so the opportunity lasts long. It should be stressed again that this apparition provides the best opportunity to catch any glimpse of the npc in a lull of the nph after λ=350Ls as well as to witness the clearing up of the nph.

07 The period (B) from λ=310Ls to λ=350Ls described in CMO #305 (25 May 2005) p2-0088 or in

is included in this apparition when the physical condition is preferable to watch the northern originated dusts: Sometimes they gave large resonances on the southern hemisphere crossing the equator (see the preceding excellent Note by Chritophe PELLIER (CPl) this issue, and also in )

In 2003, as pointed out by CPl, one example was observed at λ=315Ls by Don PARKER (DPk), and in 2005 another one was observed at around λ=310Ls. In 2007, λ=310Ls comes round on 7 September with δ=8.4" and φ=1S, and then δ and φ increase, and finally λ=350Ls visits on 19 November with δ=14.0" and φ=7N.

08 The evening cloud over Olympus Mons will cease to be active from mid-March 2007, while the Tharsis evening cloud will continue to be seen even after the summer, and we ask our observers to check its scale every time. Olympus Mons may resume showing its white aspect from the end of 2007 to the beginning of 2008. From Oceania and Asia, it may be possible to see the opposition effect of Olympus Mons and other Montes from around mid-December since the phase angle will decrease enough. It is interesting to check the CMT (how about at 3h JST on the Christmas Day?).

09 As first noted in CMO #279 or in

an area inside the morning grid [Ω=150W - 160W, Φ=00S - 10S] is de-concentrated from the morning mist and looked wine-coloured as was clearly shown in 2003 at λ=257Ls by Canon LAU (CLa). This CLa phenomenon was observed from λ=250Ls to 300Ls in 2003 (discontinuously since observations were made discontinuously, reported in CMO #289~#283), and furthermore in 2005 the wine coloured patch was again obvious on a series of images of Bill FLANAGAN (WFl) which were taken on λ=328Ls. Hence it is expected this apparition also the CLa phenomenon should be checked from June 2007 onward. However, unfortunately this time, the first half period it is difficult to see the very morning, and so we may be forced to wait until the time the phase angle decreases enough. However we should say it will be precious if anyone will be successful to detect it after the period of WFl (on λ=328Ls, 10 October).

10 Finally, since the New Year is around the corner, we summarise the situation of Mars at the beginning of 2007. On 1 January, the apparent diameter δ is a bit less than 4.0". In January it moves from Ophiuchus to Sagittarius, and so the apparent declination is southernmost. From the NH watchers the planet Mars is low at the ES sky even near dawn, and shines as a dim star of 1.5 magnitudes below at the left hand side of the planet Jupiter. Even at the end of February, it just shows the altitude of 20 from Japan.

11 In March and April, the altitude remains still low even at dawn, and the δ just reach 5.0" in mid-April as mentioned before. In May, the altitude will recover 30, and at the beginning of May the Martian season reaches λ=230Ls with φ=25S. Note already the season of southern dust has begun (on λ=215Ls in 2003 it occurred at M Serpentis).

12 In 2007, Mars does not approach any bright planets. Occultations of Mars by the Moon occur on 14 April, seen from S and E Asia and India, but not from Japan, and also on 24 December, seen from Canada to Europe. Mars will be near M20, M8 and M22 on 17, 18, and 28 January respectively. On 17 September, Mars will be near M1, and on 3 October near M35. The crab nebula M1 is in Taurus, and the open cluster M35 is in Gemini; implying readily how high up enough the planet can be seen from the NH already in September and October.

The planet will attain the western quadrature on 17 September and be stationary on 15 November at 16h.

(To be concluded in mid-2007)


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