Monthly Information about Comets in February 1997
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Japanese version Home page |
Updated on February 20, 1997 |
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Comets Ranking
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Here is the ranking of comets in February, 1997.
Comet C/1995 O1 (Hale-Bopp), one of the greatest comet in this century, is shining as 1 mag in the morning sky. It can be seen as 0-1 mag until late April easily even with naked eyes. Here I list up all phenomena until late May related to the comet Hale-Bopp. 81P/Wild 2, which will pass the perihelion in May, is bright as 9 mag in Gemini. In the evening sky, 46P/Wirtanen is also coming brighter rapidly and has already reached 11 mag. Three new comets have been discovered this year, but they are all about 17 mag. New asteroid 1997 BA6 was discovered and found to be the second one after 1996 PW which has a parabolic orbit. Though it is so faint as 19-20 mag now, it will brighten as 15 mag in 1999.
Other faint comets are as follows.
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Explanations
Comet Hale-Bopp was observed as 4 mag in December in the evening sky
until late of the month and turned to be seen at dawn since January
came.
Because the comet is so bright, it was seen twice a day, at dawn and
at dusk, around the New Year's Day.
Though the comet was so low in early January and hard to see it, it
came higher and could be seen even with naked eyes as a dimly stellar
object around 3.5 mag in mid of the month.
The total magnitude came brighter, 3.0 around Jan. 20 and 2.5 in late
January.
The wide tail spreading northwestwards about 1 deg could be seen with
binoculars.
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| Date | Mag | Altitude at dawn | Altitude at dusk | Phenomenon |
|---|---|---|---|---|
| February | ||||
| 1 | 2.2 | 22 | Seen about 5 deg over Altair | |
| 3 | 2.1 | 23 | Enters in Sagitta | |
| 7 | 1.8 | 24 | Closes 30' to the globular cluster M71 (8.3 mag, 7.1') | |
| 12 | 1.7 | 25 | Closes 3 deg to the nebula M27 (8.1 mag, 15') | |
| 13 | 1.6 | 26 | Enters in Vulpecula | |
| 24 | 1.1 | 27 | Enters in Cygnus | |
| 24-25 | 1.1 | 27 | Closes 2 deg to the Veil Nebula | |
| March | ||||
| 2 | 0.7 | 26 | Ion tail stretches to North American Nebula | |
| 4 | 0.6 | 26 | 0 | The altitude 1 hour after sunset goes over 0 deg |
| 7 | 0.5 | 25 | 2 | Enters in Lacerta |
| 9 | 0.4 | 24 | 4 | Seen during an eclipse in Mongolia and Siberia |
| 10 | 0.2 | 19 | 10 | The altitude 1 hour after sunset goes over 10 deg |
| 15 | 0.2 | 20 | 9 | Enters in Andromeda |
| 19 | 0.1 | 17 | 13 | Closes 5 deg to the open cluster NGC7686 (5.5 mag, 15') |
| 23 | 0.1 | 13 | 16 | Closest to the earth |
| 25 | 0.0 | 11 | 18 | Closes 5 deg to M31 (3.5 mag, 178') |
| 27 | 0.0 | 9 | 19 | The altitude 1 hour before sunrise goes under 10 deg |
| 28 | 0.0 | 8 | 20 | The tail spreads towards Cassiopeia |
| April | ||||
| 1 | 0.0 | 4 | 22 | Passess the perihelion |
| 5 | 0.1 | 0 | 24 | The altitude 1 hour before sunrise goes under 0 deg |
| 7 | 0.2 | 25 | Enters in Perseus | |
| 7 | 0.2 | 25 | Closes 1.5 deg to the open cluster M34 (5.1 mag, 35') | |
| 10 | 0.3 | 25 | Closes 1.5 deg to Algol (2.5 mag) | |
| 11 | 0.3 | 25 | The tail spreads towards an open cluster around alpha-Per | |
| 19 | 0.6 | 24 | Closes 3 deg to California Nebula | |
| 23 | 0.8 | 22 | Enters in Taurus | |
| May | ||||
| 9 | 1.5 | 13 | Closes 5 deg to the Moon | |
| 13 | 1.7 | 10 | The altitude 1 hour after sunset goes under 10 deg | |
| 20 | 2.0 | 4 | Enters in Orion | |
| 25 | 2.3 | 0 | The altitude 1 hour after sunset goes under 0 deg |
81P/Wild 2, which passes the perihelion on May 6, was observed about
1-2 mag brighter than expected.
Since last autumn, it has been brightening rapidly.
It was observed as about 16.5 mag in September, 15 mag in October, 14
mag in November and 12.5 mag in December.
The change of the magnitude is along the equation:
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C/1996 J1 (Evans-Drinkwater) is a new comet discovered on May 10 with
magnitude about 16.
It had been observed until July with magnitude 13.
Then it closes to the sun and has not been observable.
It is not seen this month, either.
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Comet 46P/Wirtanen, which passes the perihelion on Mar. 14, has been
brightening rapidly in the evening sky.
It has been observed as 19 mag from July and October, which is much
fainter than expected.
But it began to go brighter after that.
It was 15 mag in early December, 13 mag in early January and reached
11.5-12 mag in early February.
The light curve during this period is along:
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Comet 85P/Boethin, which passes the perihelion on Apr. 17, has finally
set in the west and not been observable already though it has not been
observed in this return yet.
It is not seen in this month, either.
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118PShoemaker-Levy 4, which is in its first return now, passed the
perihelion on Jan. 12.
This return is best, just at opposition around the perihelion date,
and has been expected to come bright as 14.5 mag.
But actually, it was coming much brighter than it.
It was as 17 -> 16 mag from July to September, 15 mag in October,
14 -> 13 mag in November 12.5 mag in December and 13 mag in
January.
It is much brighter than expected.
The magnitude equation calcualted from observations after October is:
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116P/Wild 4, which has been bright as 12-13 mag from January to July
in 1996, appears again at dawn.
It has passed the periheion on Aug. 31, 1996, but is expected to be
bright as 13-14 mag.
The altitude is still too low to see the comet in this month, 12 deg 1
hour before sunrise in late February.
But it comes 19 deg in late March.
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29P/Schwassmann-Wachmann 1 is now around the aphelion.
It has begun to be observed since last November in this season, and
total magnitude keeps 13 mag.
But the images is so diffused as several minutes and faint stellar
nucleaus is in the center.
Therefore it is hard to observe it.
Ordinary magnitude could be said as 17 mag substantially.
When it bursts out, the stellar nucleus comes 12-15 mag.
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Comet 121P/Shoemaker-Holt 2 was discovered in 1989 and is now in its
first return.
If the comet had kept the brightness at the discovery, it would have
been observed as 12-13 mag for a while.
But actually, it was recovered in November 1995 as 18 mag, which was 5
mag fainter than expected.
Then it has been as 19 mag and becomes at conjunction with the sun
around the perihelion on Aug. 20.
However, after it began to appear again at dawn in October, it was
observed as 16 mag, which was 2-3 mag brighter than
before-perihelion.
It keeps brightening gradually after that and now about 14-15 mag.
In 1989 it was discovered after perihelion, too.
So maybe this is a comet which becomes brighter after perihelion.
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126P/IRAS is a periodic comet discovered in 1983 by a satellite and
this is the first return.
It could not be observable in the Northern Hemisphere when it was
recovered as 13 mag in last August.
After it began to be seen also in the Northern Hemisphere in autumn,
it went faint gradually along the equation:
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65P/Gunn has already passed the perihelion on July 24, 1996.
It is too close to the sun and impossible to see it now.
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Faint Comets
| A famous periodic comet 2P/Encke should be brightening gradually for the perihelion on May 23. But it has been stable as 19-20 mag from July to December and no sign to be brighter appeared. It was expected to be 17 mag in late December, so the actual magnitude is about 2 mag fainter than expected. It locates in Pisces this month. But the altitude 1.5 hour after sunset is 25 deg in early February and 15 deg in mid, so it is already impossible to observe it now. The condition of this return is worst for observers in the Northern Hemisphere. It will be observable until mid February before perihelion, when it is 16 mag, and after perihelion, it reappears in August in Scorpius in the evening southern sky, when the comet is already 12.5 mag. Then it is observable until late November as 19 mag. On the other hand, the condition in the Southern Hemisphere is good. Because the comet closes to the earth as 0.19 AU on July 5, it becomes much bright in June and July. The comet appears as 7 mag in late June and goes faint 7 -> 10 mag in the high altitude at dusk in July. |
| 95P/Chiron, whose period is about 50 years and which is also registered as an asteroid (2060), is 15-16 mag about 10 deg east of Spica. It is seen high in the south at dawn in February and after midnight in March. It passed the perihelion in February and was observed as 15 mag in the last season. But the perihelion distance is so large and the magnitude changes slightly. We can trace it for a few years at least. |
| 124P/Mrkos is returning for the first time. It has been already recovered in October 1995 as 19.5 mag, but no observations are reported since it because it has been too close to the sun during 1996. It has been already seperated from the sun enough. But because it is in the southern sky, the comet is not observable in the Northen Hemisphere. On the other hand it is already seen high at dawn in the Southern Hemisphere. It moves from Scorpius to Telescopium. The perihelion date is Nov. 9, 1996 and it is 16 mag now and goes fainter after this. |
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22P/Kopff has already passed the perihelion on
July 2, 1996.
It reached 8 mag around then and went faint as 9 mag in August, 10-11
mag in September, 12 mag in October, 13 mag in November and December,
14-15 mag in January and 16 mag in early February.
The total light curve of this return since November 1994 is well along
the equation:
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| 94P/Russell 4, which passes the perihelion on 3rd of this month, is almost at opposition and seen with best condition. But the magnitude is only 16 because it is a small faint object. It loactes in the head of Virgo, about 10 deg north of Mars, and seen in the south sky after midnight. It comes to be opposition in March. It is now among the galaxies in Virgo. It passes in front of the galaxy M49 (8.3, 8.8') on Feb. 21. |
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Comet C/1996 P2 (Russell-Watson) was
discovered on Aug. 10, 1996 as 13 mag in the southern constellation
Sculptor.
It kept going fainter gradually after that along the equation:
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| 119P/Parker-Hartley is in its first return now. It had been already observed in last autumn and winter as 16-17 mag. It passed the perihelion on June 24, 1996 and was too close to the sun to observe it then. But it appeared again at dawn in last October and has been observed as 16-17 mag since then. It locates around the foot of Gemini this month, about 2 deg northeast of gamma Geini (1.9 mag). The position is overhead in the evening and the condition is so well. It is seen still as 16-17 mag. After this it can be observable until May when it comes low in the west as 18.5 mag. |
| A new comet C/1997 A1 ( NEAT ) discovered on Jan. 10 as 18.6 mag has been observed a bit brighter than the reported magnitude, about 17 mag. Though the perihelion date is June 20, it cannot be observable then because it is too close to the sun. The observable periods are until May before perihelion and after late August after perihelion. The perihelion distance is so large as 3.2 AU and it reaches only 17 mag. It was at opposition in Leo at discovery, but it moves westwards fast in Cancer in February and Gemini in March. The condition is good, around overhead before midnight in February, in the evening in March. It closes several minutes to Castor (1.6 mag) on Mar. 3. |
| A lost periodic comet D/1978 C2 (Tritton), which had not recovered in 1984 and 1990, seems to go away without being recovered this time. It is in Sextans and almost at opposition now. But because it should have already passed the perihelion and goes faint rapidly. It is 17 -> 18 mag this month and reaches 20 mag in late March. The predicted position was good just on the ecliptic but the comet was not recovered. Therefore it may be much fainter actually. |
| 32P/Comas Sola has been much brighter than expected, about 14-15 mag, from November 1995 to last March. Then it becomes at conjunction with the sun around the perihelion on Jun. 10. And it appeared again at dawn and has been observed as 17 mag in January and February, which is as bright as expected. It locates around the foot of Virgo and seen in the south at dawn as 17-18 mag. After this it is observable until May when it becomes at opposition as 19-20 mag. |
| Comet C/1996 Q1 ( Tabur ) has reached 5 mag in late September 1996 but suddenly stopped brightening and kept 6 mag for a while, then, to be very surprised, it suddenly has fade away on Oct. 20 and reached to 9-10 mag in late October. Though the perihelion date is Nov. 3, the comet has stopped the activity. The images also changed as extremely diffused one in November. It seems that only previously emitted materials were seen at that time. In December the previous materials also disappeared and even CCD could hardly confirm the image. It locates in Serpens(head) from February to March and seen in the south at dawn. It closes to several minutes to alpha Ser (2.7 mag) on Mar. 5. The condition on position is good, but it will be impossible to observe the comet. The magnitude is quite uncertain. This comet moves on a quite same orbit as that of C/1988 A1 ( Liller ) which appeared in 1988 and reached 5-6 mag. Therefore these two comets separated from each other at the previous perihelion (about 3,000 years ago) and came back again with 8 year interval. The brightening in September and fading awar in October may be the same phenomenon as that a child object of a separated comet sometimes becomes brighter than the parent nucleus temporarily. Because the discoverer of this comet lives in Australia despite having an Estonian name, the pronunciation of the name is not clear and many Japanese were confused. As a result, we can read it whichever in Aussie English style or Estonian style by the discoverer's comment. |
| A new comet C/1997 C1 ( Gehrels ) was discovered on Feb. 1 as 17.9 mag by Tom Gehrels at Lunar and Planetary Laboratory. It located in Cancer and almost at opposition. The calculated preliminary orbital elements show that it is now as far as Jupiter and passes the perihelion on April 1998, the distance is 2.2 AU and reaches 11 mag then. But periodic orbit with 17 year period can be also calculated. It shows that the comet has already passed the perihelion in last February and goes faint after this. Further observations suggest that it should be a periodic comet. But here I simulate it with a parabolic orbit. The comet moves westwards in Cancer and seen as 17 mag high in the south at midnight (February) or before midnight (March). It closes about 3-4 deg to an asteroid 1997 BA6. |
| P/1997 B1 ( Kobayashi ) is a new periodic comet with 26 year period discovered on Jan. 30 as 18 mag by Takao Kobayashi ni Oizumi, Gunma, Japan. Because it was stellar, it was reported as an asteroid at first. But following observations clarified that it has a coma and tail, then it was registered as a comet. This discovery is the first case with CCD by an amateur. This is also the faintest new comet by an amateur. It is the 11th periodic comet discovered by Japanese. The comet moves southwards in the head of Leo in February and March. It is almost at opposition and locates high in the south at midnight (February) or before midnight (March). It is almost stellar and 17 mag. The perihelion is Mar. 2, but it reaches only 17 mag. Then it fades away so rapidly and becomes 20 mag in late June. |
| Comet 107P/Wilson-Harrington, which is also registered as an asteroid (4015), passed the perihelion on Dec. 6. The comet was observed as 18.6 mag with a stellar image in January but it is about 1.5 mag fainter than expected. It moves from Pisces to Aries in February, from Aries into Taurus in March. It passes the north of Hyades in early April. It is still in the southwest sky at dusk as ever, but the altitude 1.5 hour after sunset comes as high as 40 deg. However the comet goes faint after this. It fades 17.5 -> 18.5 mag this month and reaches 20 mag in April. Because the perihelion distance is 1.00 AU, it can close to the Earth so much and be bright if the comet passes the perihelion in late September. But the condition of this return is bad and reaches 17 mag at most. |
| 100P/Hartley 1, which passes the perihelion on May 28, has been observable at dawn since last autumn but no one could observe it for a while. Finally it was detected in January as 19 mag. The position is quite same as calculated but the magnitude is about 2.5 mag fainter than expected. This time the condition is good, almost opposition around the perihelion date, but the magnitude is only 16-17 mag at most from April to May. It locates in Bootes, about 5 deg west of Arcturus. It is high in the south before midnight. It is about 18 mag now and brightens slowly after this. |
| A new periodic comet P/1996 A1 ( Jedicke ) discovered in January 1996 as 17 mag has been observed as 16-17 mag until last June. Then it was at conjunction with the sun and it appeared again at dawn. It has been 18 mag from December to February, which are as bright as expected. It locates in the south of the head of Virgo, about 15 deg south of Mars, and seen high in the south after midnight. It becomes at opposition next month. 29P/Schwassmann-Wachmann 1 is close, about 5 deg from this. The comet is observable until July when it comes low at dusk as 19 mag. |
| An asteroid (5145) Pholus, which was discovered on Jan. 9, 1992 as 17 mag, was quite a rare object. The orbital elements show that it moves on an orbit with 8.7AU perihelion distance and 90 year period. Because that is very similar to that of 95P/Chiron, which had been regarded as an asteroid for a long time and the true character is a comet, maybe this object is also a comet. But no coma was detected by the following observations. Though 5 years have already passed since the perihelion date, it can be observed still now. It was 17.6 mag in January. It still locates in Coma Berenices this month and is seen high in the south, almost overhead, after midnight. Because it is so far as 12 AU, farther than Saturn, the motion and the magnitude change are so slight. |
| 67P/Churyumov-Gerasimenko, which passed the perihelion in January 1996 and reached 11 mag then, has not been observable at conjunction with the sun after it faded as 14.5 mag in June. Though it should have appeared again at dawn as 18 mag since December, no one could detect the image. Actual magnitude seemed to be much fainter. This comet has become a bit brighter after perihelion and gone faint more slowly than expected. But depending on the rapidity of magnitude change before perihelion, it should be fainter than 20 mag now. It locates in the body of Virgo and seen in the south at dawn in February and before midnight in March. |
| C/1994 J2 ( Takamizawa ), which was discovered in May 1994 and was observed as 9-10 mag in May and June, has been observed for a long time and even now. It was about as bright as 15 mag in autumn in 1995, 16.5 mag in early 1996. It has been observed as 18 mag in December and January. It will be observed as 19 mag until April when it comes low in the west. The comet is now in the bottom of Orion and seen in the evening in the south in February, in the southwest sky in March. It is about 2 deg northeast of Rigel (0.1 mag) during February. |
| 91P/Russell 3, which passes the perihelion on Nov. 19, was so faint as 20-21 mag last November and December. Now it brightenes a bit and is seen as 19 mag. It locates in Crater and in the south after midnight. The condition of this return is worst and it cannot be observable around the perihelion because of the conjunction with the sun. So the chance to see this comet is around the opposition, in March and April, though it reaches only 18 mag. |
| 129P/Shoemaker-Levy 3 was recovered in October with a predicted magnitude, 19 mag. The perihelion date is Mar. 4, 1998, about one year ahead, but the orbit is like a circle, the eccentricity is 0.25, and it has already been a CCD target. It has been observed as 19 mag until December. It moves from Pisces to Aries in February and locates in the west at dusk. It passes about 40' south of the galaxy M74 (9.1 mag, 10') on Feb. 2. In March it locates still in Aries, but the altitude becomes too low to observe it. After that it appears at dawn again as 18-19 mag in August. Though it is observable until 1999, this comet is a small one and reaches only 17 mag around the perihelion. |
| 48P/Johnson, which passes the perihelion on Oct. 31, has been observed as 21 mag last spring but no other observations succeeded since then. It was at conjunction and could not be observable for a while, but it appears again at dawn. In February it locates in Serpens (tail) and the altitude 1.5 hour before sunrise changes 20 -> 25 deg, in March it enters into Scutum and the altitude changes 25 -> 30 deg. It passes among nebulae and clusters in Sagittarius in February. The magnitude is about 19 now. It brightenes to 16-17 mag at opposition in July. |
| An new asteroid 1997 BA6, discovered on Jan. 31 as 19.4 mag, was found to move on a parabolic orbit like a comet by the orbital elements calculated with following observatoins. This is the second case after 1996 PW discovered in last August. It is now so far as 9 AU, almost same as Saturn, and so faint as 19-20 mag. But it is expected to pass 3.5 AU from the sun at perihelion in December 1999 and to become 15-16 mag then. The coma or tail may be observed before that. However it locates near the South Pole around the perihelion and cannot be observed in the Northern Hemisphere. It locates in Cancer this month and seen high in the south before midnight. C/1997 C1 ( Gehrels ) is in the neighborhood, about 3-4 deg away from this. |
| A new asteroid 1996 PW was discovered on Aug. 9, 1996 as 18 mag. But the true character is a quite rare object. The orbital elements show that it moves on an orbit with 2.5AU perihelion distance and 3000 year period. That is a typical one of a long periodic comet. But the following observations say that it is quite stellar as 17 mag and no sign as a comet has been detected. It has already passed the perihelion on Aug. 8, 1996 and it should be so faint as 19-20 mag now. It locates in Cetus but has been already too low in the west. The altitude 1.5 hour after sunset changes 20 deg in early February, 5 deg in late February. So it is impossible to observe it now. mag this month. It is near Fomalhaut in early December and moves to It will appear again at dawn in July but the magnitude should be so faint as 20-21 mag. Then this object goes far away from our solor system and will never be observed again. |
| 88P/Howell, which will pass the perihelion in September 1998, has not been observed yet in this return. But now it is at opposition and the chance to detect it with a large telescope, though it is so faint as 20 mag. It locates in Leo in February, Cancer in March. It is seen high in the south at midnight. This comet will be 11 mag around the perihelion. |
| A famous periodic comet for its quite small q (0.12 AU), 96P/Machholz 1, has not been detected yet in this return, though it has passed the perihelion in last October. The condition of this return is worst to see the comet in the Northern Hemishpere and could never observe it. It has been slightly observable in August and September in the Southern Hemisphere. But no observations succeeded. It kept close to the sun after that and the comet should have gone faint rapidly. It locates in Sagittarius now. The altitude 1.5 hour before sunrise is 13 deg in late February, 23 deg in late March. It barely comes to be seen in the Northern Hemisphere. However the magnitude is already so faint as 21 mag. Therefore it is almost impossible to observe this comet. Depending on http://cfa-www.harvard.edu/cfa/ps/icq/CometMags.html, the SOHO satellite has observed this comet on Oct. 13 and 14 as 4.5 mag with the coronagraph. But anyway, probably no one can see this comet in this return after all. |
Ephemeris Table
m1 = -0.3 + 5 log d + 7.5 log r
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m1 = 3.5 + 5 log d + 25.0 log r
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m1 = 6.5 + 5 log d + 10.0 log r
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m1 = 8.5 + 5 log d + 27.0 log r
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m1 = 6.5 + 5 log d + 20.0 log r
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m1 = -6.0 + 5 log d + 60.0 log r
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m1 = 1.4 + 5 log d + 27.0 log r
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m1 = 4.0 + 5 log d + 7.5 log r
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m1 = 6.5 + 5 log d + 15.0 log r
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m1 = 8.5 + 5 log d + 15.0 log r
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m1 = 7.7 + 5 log d + 10.0 log r
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m1 = 11.0 + 5 log d + 12.0 log r
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m1 = 4.0 + 5 log d + 7.5 log r
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m1 = 12.0 + 5 log d + 10.0 log r
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m1 = 5.3 + 5 log d + 21.0 log r
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m1 = 10.5 + 5 log d + 15.0 log r
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m1 = 5.6 + 5 log d + 12.0 log r
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m1 = 2.0 + 5 log d + 25.0 log r
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m1 = 9.5 + 5 log d + 10.0 log r
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m1 = 13.0 + 5 log d + 20.0 log r
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m1 = 5.3 + 5 log d + 22.5 log r
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m1 = 11.2 + 5 log d + 20.0 log r
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m1 = 7.5 + 5 log d + 10.0 log r
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m1 = 14.2 + 5 log d + 10.0 log r
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m1 = 16.5 + 5 log d + 5.0 log r
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m1 = 11.5 + 5 log d + 20.0 log r
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m1 = 4.2 + 5 log d + 15.0 log r
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m1 = 7.5 + 5 log d + 5.0 log r
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m1 = 9.3 + 5 log d + 11.5 log r
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m1 = 4.2 + 5 log d + 10.0 log r
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m1 = 7.5 + 5 log d + 20.0 log r
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m1 = 11.0 + 5 log d + 10.0 log r
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m1 = 10.0 + 5 log d + 15.0 log r
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m1 = 10.0 + 5 log d + 5.0 log r
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m1 = 14.0 + 5 log d + 5.0 log r
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m1 = 8.0 + 5 log d + 15.0 log r
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m1 = 13.0 + 5 log d + 12.0 log r
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Finding Charts (PostScript)
These finding charts are made with
StellaNavigator Ver.2.0 for Windows (AstroArts / ASCII)
.