Rothko painting, Koons moon sculpture star at New York City art auction

A radiant painting by Mark Rothko and a reflective sculpture of the moon by Jeff Koons are among the stars at the second day of New York's dazzling post-war and contemporary art auctions.

"No. 21 (Red, Brown, Black and Orange)," which was purchased by art benefactors Pierre and Sao Schlumberger directly from Rothko's estate, could bring over $50 million at Sotheby's on Tuesday evening.

The abstract 1951 work comes up for bid a day after the auction house sold two other paintings by Rothko from the estate of Listerine fortune heir Rachel "Bunny" Mellon for a combined total of $76 million.

Also coming up for bid Tuesday at Sotheby's is Koons' "Moon (Yellow)," which could bring between $12 million and $18 million. It is one of five mirror-like moon sculptures Koons created in different colors. A pink version was displayed at the recent Koons retrospective at the Whitney Museum of American Art.

The stainless steel 11-foot work could create quite the buzz — last year Koons became the most expensive living artist when his "Balloon Dog (Orange)" was auctioned for $58.4 million.

Rothko's "No. 21" has never been offered at auction. The painting was first exhibited in the seminal exhibition "15 Americans" at the Museum of Modern Art in New York in 1952, a year after it was created. It has not been exhibited since a traveling retrospective of Rothko's work in 1971-72.

The current Rothko auction record is $86.8 million for "Orange, Red, Yellow."

Among other highlights is Andy Warhol's 1974 "A Group of Four Portraits of Sao Schlumberger," estimated to sell for between $2 million and $3 million.

Schlumberger died in 1986; his wife passed away in 2007. They were central figures in New York and Parisian society who helped fund the restoration of Versailles. They were patrons of the Pompidou Center, The Museum of Fine Arts in Houston and the Museum of Modern Art and Lincoln Center in New York. They also were the first patrons to commission Warhol for a silkscreen portrait.

Other works in Tuesday's sale include one of Jasper Johns' iconic flag paintings. The example at Sotheby's was acquired directly from the artist in 1983 and has remained in the same private collection since. It recently was on loan at the Philadelphia Museum of Art and previously exhibited at the Rhode Island School of Design and Yale University Art Gallery. "Flag" has a pre-sale estimate of $15 million to $20 million.