The man who murdered Sherri Slack’s 22-year-old brother a decade ago is getting out of jail this year, so she wanted to do something special to help her parents remember their son.

Slack found her gift in Name a Star (search) -- one of many companies that claim to name stars after people -- for $49.95, plus shipping.

“I got it for them this Christmas ... I wanted my parents to be able to look up so they wouldn’t have to go to the cemetery. They were ecstatic,” said Slack, a Delaware resident.

But there's a wrinkle in the twinkle. Star names sold by commercial enterprises “have no formal or official validity whatever," according to the International Astronomical Union (search), the recognized authority for naming celestial bodies and their surface features.

“As an international scientific organization, the IAU dissociates itself entirely from the commercial practice of ‘selling’ fictitious star names or ‘real estate’ on other planets or moons in the Solar System,”  the IAU says in a statement on its Web site.

The IAU actually assigns numbers rather than names to most of the hundreds of millions of stars in the sky, with the exception of a relatively few asteroids named for people like Fred (Mister) Rogers and Frank Zappa.

Space.com science writer Robert Roy Britt believes that most star-naming services intentionally deceive people into thinking the celestial body they have purchased has been officially re-named, when this is not the case.

He also points out that two star-naming services can sell two individuals the same exact piece of heaven, both while promising a "unique" star with an exclusive name.

“What they’re doing is in most cases very deceptive," Britt said. "Even if you do read the fine print, most companies make very little effort to explain what you really get for fifty bucks – a nice piece of paper. And several make overt attempts to sound official when they’re not.”

But Slack said she's aware that her star name is not recognized by astronomers – and she doesn’t care.

“My nephew was just born premature on Dec. 11. The night he was born, the Big Dipper was out. That’s him.

“Name a Star guaranteed our star would be located in a spot that would be easily seen – it’s in the Big Dipper. They give you this sheet with the constellation and it gives you the star exactly. I’m really bad [at locating stars] and I can find it,” she said.

And some of the biggest fans of buying stars are ... stars. Oprah Winfrey, in a segment on her show called “The Best Money I Ever Spent,” presented two Big Dipper stars from Name a Star to a woman who had lost her mother and her sister.

She's reportedly not the only luminary to do so.

“We’ve had Brittany Murphy a couple of times … we also did one for the "X-Files" in the shape of a big X after they taped the last show," said Name a Star owner Tonya Vaughan. "Somebody did one for Garth Brooks’ mom, and somebody got one for Liza Minnelli, for her last marriage."

Another company, the International Star Registry (search), claims on its Web site to have sold "a place in the cosmos" to hundreds of thousands of people, including celebrities and dignitaries -- for $54 a pop.

Name a Star's marketing director (and Vaughan's husband) Cort Vaughan admits that their service provides a novelty, rather than official, gift.

"It's primarily for the enjoyment of those giving and receiving the star," he said.

Indeed, Britt, in his article lambasting the services, counts Name a Star among the more forthright star-sellers. And even he says that while naming a star is “completely unofficial,” some people might like to do it anyway.

“I have heard from several readers who said you should leave us alone and let us name a star if that’s what we want to do," he said.