Is the word abertas the same in Brazilian and European Portuguese?

Yes

The word "abertas" is identical in both Brazilian and Continental Portuguese in terms of meaning, spelling, and grammar. The only difference lies in pronunciation. Brazilian Portuguese features more "open" vowels, where each syllable is clearly articulated. In Continental Portuguese, unstressed vowels are subject to significant "vowel reduction," meaning the "e" and "a" in "abertas" are often shortened or nearly swallowed, making the word sound more consonant-heavy.

Brazilian Portuguese examples:

1. As janelas estão abertas. (The windows are open.)
2. Elas deixaram as portas abertas. (They left the doors open.)
3. As inscrições estão abertas para o curso. (Registrations are open for the course.)
4. As oportunidades estão abertas para todos. (Opportunities are open to everyone.)
5. As lojas ficam abertas até as dez da noite. (The stores stay open until ten at night.)

Continental Portuguese examples:

1. As janelas encontram-se abertas. (The windows are open.)
2. As portas ficaram abertas. (The doors were left open.)
3. As inscrições encontram-se abertas para o curso. (Registrations are open for the course.)
4. As oportunidades estão abertas para todos. (Opportunities are open to everyone.)
5. As lojas ficam abertas até às dez da noite. (The stores stay open until ten at night.)