Harvard professor and former presidential advisor Elizabeth Warren will announce Wednesday she is officially in the race to unseat US Sen. Scott Brown. Aides say she will greet commuters in Boston in the morning before travelling to New Bedford, Framingham, Worcester, and Springfield.

“The pressures on middle class families are worse than ever, but it is the big corporations that get their way in Washington,” Warren said in a statement. “I want to change that.  I will work my heart out to earn the trust of the people of Massachusetts.” 

Warren will join a crowded field with seven other Democrats vying for the nomination. She has been meeting with small groups at invitation-only gatherings in kitchens and living rooms listening to people around the state and introducing herself to many who know little about her.

Since she was passed over by President Obama to head the new Consumer Financial Protection Bureau, whose creation she oversaw, because of Republican opposition, she has been mulling a run for the seat with the backing of national Democrats.

Warren is an unknown, compared to Brown’s rock star status. According to a WBUR poll last week performed by the MassINC Polling Group. 44 percent of voters in the state had never heard of her, compared to just 5 percent for Brown. But that is the lowest of all the Democratic contenders, and in a head-to-head match, only Warren is within single digits of Brown, 44 to 35, before she had even entered.

The other announced candidates include City Year cofounder Alan Khazei; Newton Mayor Setti Warren; Robert Massie, the 1994 Democratic nominee for lieutenant governor; state Rep. Thomas Conroy; Salem attorney Marisa DeFranco; Herb Robinson, an engineer from Newton; and Boston lawyer Jim King.

                                                                                                                                                        –JACK SULLIVAN