On the Use of the Term “Planet 9” for Objects Beyond Pluto

We the undersigned wish to remind our colleagues that the International Astronomical Union (IAU) planet definition adopted in 2006 has been controversial and is far from universally accepted. Given this, and given the incredible accomplishment of the discovery of Pluto, the harbinger of the solar system’s third zone — the Kuiper Belt — by planetary astronomer Clyde W. Tombaugh in 1930, we the undersigned believe the use of the term “Planet 9” or "Planet Nine" for objects beyond Pluto is insensitive to Professor Tombaugh’s legacy.

We further believe the use of this term should be discontinued in favor of culturally and taxonomically neutral terms for such planets, such as Planet X, Planet Next, or Giant Planet Five.

Paul Abell
Michael Allison
Nadine Barlow
David Bartlett
James Bauer
Gordon Bjoraker
Paul Byrne
Eric Christiansen
Rajani Dhingra
Timothy Dowling
David Dunham
Tony L. Farnham
Harold Geller
Alvero Gonzalez
David Grinspoon
Will Grundy
George Hindman
Kampalayya M. Hiremath
Brian Holler
Stephanie Jarmak
Martin Knapmeyer
Rosaly Lopes
Amy Lovell
Ralph McNutt
Phil Metzger
Sripada Murty
Michael Paul
Kirby Runyon
Ray Russell
John Stansberry
Alan Stern
Mike Summers
Henry Throop
Hal Weaver
Larry Wasserman
Sloane Wiktorowicz