I'm also including an actual story of one of my visitors who had already "purchased" a star.
If you want to pay someone to send you a certificate with some stellar coordinates, a star map and a letter, there are companies that do exactly that. However, be aware that this is little more than a novelty item and, often, an expensive one. There is nothing official about the name nor is there any guarantee that the star you've "purchased" hasn't been sold to someone else by another company in the same business.
There are about 6000 visible stars in the night sky. If the numbers reported by one of these dealers in star names are correct, all of those have been sold. Therefore, if you were to buy a star, it's unlikely that you'd even be able to see it.
Below is a recount of a visit I received from someone who had purchased a star name from a company. It will give you an idea of what he received for his money.
Today, the International Astronomical Union is the governing body regarding the names of stars, planets, moons and other celestial bodies. Their power derives from an agreement among the world's astronomers and international treaty. If you buy a star name from a company, it will not be recognized by the IAU.
The IAU does not sell stars or star names. Click here for their statement on the buying and selling of star names.
Asteroids are generally given a numeric designation. However, the IAU has, in the past, given names to them based on suggestions they receive from the discoverer. The names generally derive from scientists, artists, musicians, etc. Click here to search a list of asteroids that have been named. Maybe you'll find your name in that list.
When he arrived, he told me that he'd received a certificate with coordinates for his star, a star map with his star circled, a letter from the company congratulating him on his place in the heavens and an order form for the book with his name in it. Unfortunately, he brought none of this with him. He'd written down the coordinates on the back of a supermarket receipt.
First I went to my computer and checked the coordinates using an astronomy program. Then I used a second program. Finally I pulled up a third program which showed stars to 15th magnitude*.
I explained to him that astronomers use fairly high precision numbers for stellar coordinates. The coordinates he had were only accurate to minutes of arc rather than seconds of arc.** Within a one arc minute circle, there were half a dozen stars. I told him he could take his pick.
We went into the planetarium where I pointed out the region of the sky where his star resided. Naturally, because our planetarium only shows stars down to about 6th magnitude, there was nothing for us to see.
I'm not exactly sure how the next turn of events took place but he demanded to see my supervisor. When the boss came down, my visitor complained about my inability to show him the star he'd bought. From his perspective, if I couldn't find his star, I must not know much about astronomy. My boss, who just retired after 33 years in the planetarium field, told him that he couldn't find it either; it was just too dim.
The guy was pretty hot under the collar when he left and I haven't seen him since.
If, however, you'd like to buy an astronomical gift of a different nature, I have the
following suggestions:
Please do not contact me asking for the names or addresses of companies who deal in the selling of star names.
For more information see The OFFICIAL Star Naming FAQ.
*Magnitude is the measurement of the brightness of a star. The higher the number, the
dimmer the star. The dimmest stars visible to the naked eye are about 6th magnitude.
**An arc minute is 1/60 of a degree. An arc second is 1/60 of an arc minute or
1/3600 of a degree.