The Sun (Tai Yang, 太阳) star

What the classic Zi Wei Dou Shu Quan Shu (紫微斗数全书) says it is

Fire, the essence of the sun. It is the outward sign of creation, and in the reckoning it gives a person an air of honour and the ability to serve in civil or military office. Benefics gathered, it sends down good omens; among dark stars, it means toil and effort. Falling in the Self and seated on strong ground it is the highest star of the reckoning and the hinge of the Career palace. Its transformations are to honour and to income, and it is best in Career. For a man it is the father star, for a woman the husband. The Self meeting benefics guarding and shining, and the Moon (太阴) shining with it, means wealth and rank complete. Holding the Body with benefics gathered, one may be a guest at the gate of the honoured; otherwise a runner for the great. Spouse is a strong palace too: for a man with benefics gathered, honour may come through the wife; badly placed with malefics, injury to the wife and not favourable. In Children with the Eight Seats (八座) and benefics well placed, honoured children with no small authority. In Wealth on strong ground with benefics helping, it does not fear the Voice (巨门) winding round it, and the wealth and rank run long. Strong and with no the Void and the Plunder (空劫), wealth for a life. In Property, the shade of the ancestors. If the two Aides (左右) and the benefics all arrive and both limits come at once, there is sudden rising to be glad of; if the limit does not support it, do not argue from the trine, for the answer may be a little out. A woman meeting it with a strong limit may enjoy it too. With the Ember (铃星), the Punisher (天刑) and the Trouble transformation (化忌) gathered in a limit, there is trouble at hand, or harm to a parent. With punishment and malefics gathered, an official has an injured post to grieve over and a commoner is troubled by legal matters. With the Blade (擎羊) and the Millstone (陀罗) gathered there is illness; with the Flare (火星) and the Ember, no small suffering. In Travel its blessing is unlike the Self: the ancestral inheritance is hard to take up, the root is moved and the leaf changed, and one leaves home to make a household. A limit meeting it there means moving, for certain. In Wellbeing with assistance, a woman draws a wise and clear-sighted husband. In Parents, for a man it is the father star alone: with light it is favourable, without light it harms the father. Master Xiyi (希夷先生) says: The Sun (太阳) turns through the degrees of heaven without end. It welcomes the two Aides assisting the ruler and the Hoard (禄存) to help its blessing. What it dislikes is meeting the darkness of the Voice; what it delights in is the Moon strong beside it. Meeting benefics in any palace is favourable; met on the dark road it is toil. Holding the Self it makes a person loyal and plain-spoken, not given to arguing right and wrong. Well placed with the Fortune transformation (化禄) or the Power transformation (化权) it may fairly be judged honour. Getting the two Aides, the Scholar and the Artist (昌曲) and the two Patrons (魁钺) in trine shining on Wealth and Career, wealth and rank of the highest grade. With the four malefics added, still warm and fed; for a monk, a teacher's title. A woman well placed is good for husband and children, and with Power or Fortune receives a title; with malefics, ordinary. The song runs: The Sun is Fire by nature, the true ruling star of Career. Sitting in the Self, the nature is the cleverest of all — kind, wide in measure, with blessing and long years. Meeting the Moon, sudden honour beyond compare. With light shining on the Self, one walks easily through the golden gate. Where the Voice does not offend it, one climbs the hall and receives the ruler's favour. In a sideways palace met by darkness, poverty past speaking; a man must harm his father, a woman's husband is not whole. If the Flare and the Ember settle on it, and the Blade and the Millstone, the eyes grow dim. When the two limits fall here, land and garden are certainly sold. Master Yuchan (玉蟾先生) says: The Sun governs authority and honour as a civil star; meeting the Punisher it is military. At Tiger (寅) and Rabbit (卯) it is first rising; at Dragon (辰) and Snake (巳) it ascends the hall; at Horse (午) it is the sun at noon in mid-heaven and means great wealth and rank; at Goat (未) and Monkey (申) it is a sideways wall, diligent first and idle after; at Rooster (酉) it sets in the west, honoured but not prominent, fine but without fruit; at Dog (戌), Pig (亥) and Rat (子) it has lost its light, and meeting darkness besides it is a life of toil, poverty and hurry, with injury to the eyes and few people it agrees with. With the Hoard in the same palace it means wealth, but hard and unresting; with the two Aides it may be judged honour. It dislikes the Flare and the Ember (火铃), the Punisher and Trouble, which do not spare the father. For a man this star is the father, for a woman the husband.

答曰：太陽星屬火，日之精也。乃造化之表儀，在數主人有貴氣，能為文為武。諸吉集則降禎祥，處黑星則勞心費力。若隨身命之中，居於廟樂之地。為數中之至曜，乃官祿之樞機。後化貴化祿，最宜在官祿宮。男作父星，女為夫主。命逢諸吉守照，更得太陰同照，富貴全美。若身居之，逢吉聚，則可在貴人門下客，否則公卿走卒。夫妻亦為強宮，男為諸吉聚，可因妻得貴。陷地加殺，傷妻不吉。男女宮得八座，加吉星在廟旺地，主生貴子，權柄不小。若財帛宮於旺地，會吉相助，不怕巨門纏，其富貴綿遠矣！若旺相無空劫，一生主富。居田宅，得祖父蔭澤。若左右諸吉星皆至，大小二限俱到，必有驟興之喜。若限不扶，不可以三合論議，恐應小差。女命逢之，限旺亦可共享。與鈴刑忌集限，目下有憂，或生剋父母。刑殺聚限，有傷官之憂，常人有官非之撓。與羊陀聚則有疾病，與火鈴合其苦楚不少。推而至此，禍福了然。遷移宮其福與身命不同，難招祖業，移根換葉，出祖為家。限步逢之，決要動移。女命逢之不吉，若福德宮有相佐，招賢明之夫。父母宮男子單作父星，有輝則吉，無輝克父。希夷先生曰：太陽星周天曆度輸轉無窮。喜輔弼而佐君象，以祿存而助福。所忌者，巨暗遭逢。所樂者，太陰相旺。諸宮會吉則吉、黑道遇之則勞。守人身命，主人忠鯁，不較是非。若居廟旺，化祿化權，允為貴論。若得左右、昌曲、魁鉺三合拱照財官二宮，富貴極品。加四殺，亦主飽暖，僧道有師號。女人廟旺，主旺夫益子，加權祿封贈，加殺主平常。歌曰太陽原屬火，正主官祿星，若居身命位，稟性最聰明，慈愛量寬大，福壽享遐齡，若與太陰會，驟發貴無倫，有輝照身命，平步入金門，巨門不相犯，升殿承君恩，偏垣逢暗度，貧賤不可言，男人必克父，女命夫不全，火鈴逢若定，羊陀眼目昏，二限若值此，必定賣田園。玉蟾先生曰：太陽司權貴為文，遇天刑為武。在寅卯為初升，在辰巳為升殿。在午為日麗中天，主大富貴。在未申為偏垣，作事先勤後惰。在酉為西沒，貴而不顯，秀而不實。在戌亥子為失輝，更逢巨暗一生勞碌貧忙。更主眼目有傷，與人寡合招非。女命逢之，夫星不美，遇耗則非禮成婚。若與祿存同宮，雖主財帛，亦辛苦不閑。若與左右同宮則為貴論。又嫌火鈴、刑忌，未免先克其父。此星男得之為父星，女得之為夫星。