Comet C/2007 N3 (Lulin) the highlight comet of this season is presently gracing the eastern skies. From January 2009 the comet has been rapidly getting higher and brighter, as it glides westwards from zodiacal constellations Libra (scales), Virgo (maiden), Leo (lion), Cancer (crab) and Gemini (twins). It is swinging around the Sun with incredible average speed of circa fifty five kilometers per second. It was at perihelion (closest position to Sun) on 10 January at sheer 182 million kilometers. Its aphelion (furthest point to Sun) is estimated to be unimaginably 270 thousand AU away. One Astronomical Unit (AU) is defined as the mean Sun to earth distance that measures solely 150 million kilometers. Its approximate orbital period has been calculated to be fairly 49.5 million years. Lulin is a long-period comet. Since its course is moderately parabolic, it could be concluded that its next visit to our inner Solar System would not probably repeat in foreseeable future. Its coma contains toxic cyanogen gas (CN)2 and diatomic carbon (C2) which glisten alluringly green when irradiated by sunlight (resonant fluorescence). Thus its green colour is produced by these gases as it rushes through vacuum of outer space. The size of Lulin is perhaps five hundred thousand kilometers across (simply four times bigger than Jupiter or utterly seventy five times more immense than earth). Comet Lulin is travelling almost along the ecliptic (apparent avenue traced by Sun across the sky annually) and weirdly backwards.
On 05/06 February comet was rising around midnight and had drifted within close proximity of double star Alpha Librae (Zubenelgenubi or Vishaka). Lulin will be creeping into Virgo from Libra and sail by Lambda Virginis (northeast of star Spica alias Chitra). On 16 February, Lulin will pass three degrees north of Spica. On 23 February, virtually quite resplendent, it would sit fourty degrees above horizon. Its illumination would peak and would shine exquisitely just two degrees southwest of Saturn on 24 February. Lulin’s nearest approach to earth of 61 million kilometers occurs on this day. The comet should be beautifully lustrous and be visible all night, rising in the east at dusk, climbing maximum in the southern sky promptly after midnight and setting in west around sunrise. Its dusty coma and debris tail would be intensely lambent.
In the evening of 27 February it would slip within one degree south of reddish star Leo-star Regulus (Magha). It crosses from Leo into Cancer at the beginning of March. On 05 March it would slide within two degrees of star Delta Cancri (Assellus Australis or Pushya) and the Beehive Cluster (M44). On 16 March it is one degree from Delta Geminorum (Wasat). As Comet Lulin recedes from Sun, its passage across our sky will be slow. From the end of March to the end of May, when Lulin may have evanesced substantially, it would stay within strictly narrow, three degrees strip of sky bounded by stars Mebsuta, Mu, and 36 Geminorum in Gemini. By May's end Lulin will be lost in the afterglow of sunset.
Comet Lulin was recognized by 19-year old student Quanzhi Ye from Sun Yat-sen University in mainland China from the images (considered to be that of asteroids) taken by Chi Sheng Lin with telescope at Lulin Observatory in Taiwan on the night of 11 July 2007. Lin was ardently exploring under Lulin Sky Survey Project populations of bodies in Solar System that pose potential hazards to earth. In coming weeks it will be favourably placed for enjoying its awesome apparition in the evening sky well through binoculars or telescopes. Otherwise sharp-eye viewers could discern it as dim and fuzzy star.
Experts think that comets could have delivered water during their innumerable impacts on early earth. Some researchers speculate hypothetically that comets may have seeded precursors of life on our planet. Meteor showers (shooting stars) are caused when earth passes through their debris trails. Though comets were deemed ominous harbingers in many cultures, comet like Lulin still reveal precious information on the evolution of our Solar System and eventually on origin of life on earth.
(Note:It is the press release issued by Nepal Astronomical Society(NASO) on February 16,2009)