More details about the new phones replacing Google's Nexus line have emerged just ahead of the company's big launch event tomorrow. Over the weekend, a trio of sites published -- and then unpublished -- images and product listings for Google's Pixel and Pixel XL smartphones, expected to make their debut October 4.

The phone details, listed online briefly by Canadian telcos Bell and Telus and by UK retailer Carphone Warehouse, show the 5-inch Pixel and 5.5-inch Pixel XL will be available in at least two colors -- black and white -- and appear positioned to compete against C

Both phones will feature Qualcomm's Snapdragon 821 processor, a 12.3-megapixel camera and 4 GB of RAM, and will be available with either 32 GB or 128 GB of storage. Both will also run Google's latest version of Android, 7.1 Nougat.

Google Assistant, Fast Charging

Rumors about what might replace Google's Nexus line have been circulating since earlier this year, when the company brought on board former Motorola president Rick Osterloh to lead a new hardware division. Google released its first Nexus phone in 2010, and has partnered with several different original equipment manufacturers since then.

While the prematurely posted Pixel listings did not include price information for either the Pixel or Pixel XL, previous leaks have said the Pixel is likely to carry a price-tag of $649, which means the larger phone will probably cost even more.

Other specs revealed for the new phones show the Pixel will have a full-HD AMOLED, Gorilla Glass 4 display and a 2,770 mAH battery, while the Pixel XL will come with a QHD AMOLED Gorilla Glass 4 display and a 3,450 mAH battery. Images published on Carphone Warehouse show the phones will also feature a reversible USB Type-C charger that supports fast charging, delivering "up to 7 hours of battery life in just 15 minutes."

In addition, the images highlight the arrival of Google Assistant on the new phones. Announced at Google's I/O developers conference this past May, Google Assistant is an intelligent software persona that provides conversation-based answers and help to users.

New OS or Platform Announcement?

Scheduled to begin Tuesday, Oct. 4 at 9 a.m. Pacific Time, Google's livestreamed event is also expected to feature several other product announcements. Among the products likely to be unveiled are 4K Chromecast, Google's new Daydream virtual-reality viewer and Google Home, a smart-home device that's been widely compared to the Amazon Echo.

Hiroshi Lockheimer, Google's senior vice president of Android, Chrome and Play, also hinted at some potential new operating system news in a recent tweet. Posting on Sept. 24, Lockheimer wrote, "We announced the 1st version of Android 8 years ago today. I have a feeling 8 years from now we'll be talking about Oct 4, 2016."

According to a report today on Quartz, it's possible Google could be planning to announce a "new operating system or computing platform that combines aspects of Android, its mobile operating system, and Chrome, the OS used on its netbooks."

Check back with us tomorrow for full coverage of Google's launch event and pictures of the new phones.