Michael Schumacher’s return is only part of an intriguing Formula One season

Schumi’s back behind the wheel, Danica’s back to her day job and the Formula One and IndyCar series are back in action for 2010.

Formula One launches its 19-race season Sunday with the Bahrain Grand Prix, highlighted by the return of seven-time champion Michael Schumacher, 41, who has emerged from retirement to drive for the newly named Mercedes GP team, formerly Brawn GP.

The Izod IndyCar Series, meanwhile, opens in South America with a race Sunday on the streets of Sao Paulo, Brazil. Reigning champion Dario Franchitti will be vying for another title run against the likes of teammate Scott Dixon, native Brazilian Helio Castroneves and Danica Patrick, who is coming off her initial foray into NASCAR stock-car racing.

Schumacher’s return is only one reason why Formula One’s season is chock full of intrigue. Several other drivers have changed teams, new rules could change race strategies, a new championship points system is in place and there are three new teams: Lotus, Virgin and HRT, formerly called Campos.

But the field doesn’t include a new American team, USF1, which failed to be ready in time for this season.

“I feel like a child looking forward to Christmas,” Schumacher said of his return following the longtime Ferrari driver’s retirement after the 2006 season. “I feel fresher than I have for many years. I am perfectly prepared physically and, most importantly, my energy is back completely.”

That can’t be good news for his rivals, starting with reigning Formula One champion Jenson Button, who won the title last year with Brawn and then moved to the McLaren team where he has joined 2008 champion Lewis Hamilton. Button also is the defending winner at Bahrain.

Other notable driver shifts include two-time champion Fernando Alonso moving from Renault to join Felipe Massa at Ferrari, and Robert Kubica leaving BMW Sauber to replace Alonso at Renault.

Formula One also adjusted its championship points system to try to shift the emphasis to winning races from merely collecting points. Winners will get 25 points rather than the previous 10, and the top 10 finishers will be awarded points on a sliding scale. The old system awarded points only to the top eight finishers.

And Formula One has banned refueling during races for the first time since 1993, so cars will start with enough fuel to go the distance. That means a typical pit stop will be for tires only and thus much shorter than before — probably less than four seconds.

More than 6,000 miles away, the IndyCar Series’ Sao Paulo Indy 300 in Brazil is a new event on the 17-race schedule, which also includes the Toyota Grand Prix of Long Beach on April 18 and the series’ crown jewel, the Indianapolis 500, on May 30.

The series’ biggest question again this year is whether anyone can challenge the top two teams, owned by Chip Ganassi and Roger Penske, whose drivers won all but one of last year’s races.

Ganassi’s drivers are Franchitti, who won the title last year, and Dixon, who was champion in 2008. (Franchitti also won the championship in 2007 with Andretti Green Racing, now called Andretti Autosport.) Penske’s drivers are Castroneves — who won his third Indianapolis 500 last year — and Ryan Briscoe and Will Power.

Castroneves, 34, said Wednesday that he was “excited to be racing close to my home fans” in Brazil to start the season and that, as a new father, “I cannot wait to be on the podium with my daughter.”

He also hopes to finally win his first championship, but he told reporters in a teleconference from Sao Paulo that “I’m going to approach the season the same way I’ve approached it in the past [because] I’ve been competitive.”

And if Franchitti, Dixon or someone else wins the IndyCar title instead, Castroneves said he would have no regrets.

“I can’t control that, unfortunately,” he said.

james.peltz@latimes.com