523 citations · 5.2k across the 92 of their papers we have counts for
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Towards an understanding of the Of?p star HD 191612: optical spectroscopy
Ian D. Howarth, Nolan R. Walborn, Danny J. Lennon +17
We present extensive optical spectroscopy of the early-type magnetic star HD 191612 (O6.5f?pe-O8fp). The Balmer and HeI lines show strongly variable emission which is highly reprod…
The Galactic O Star Catalog V.2.0
A. Sota, J. Maíz Apellániz, Nolan R. Walborn +1
The Galactic O star catalog (GOS) is an ambitious project to provide as much information regarding these types of objects as possible. The first version of the catalog (GOS v1) inc…
The stellar upper mass limit in the solar neighborhood
J. Maíz Apellániz, Nolan R. Walborn, N. I. Morrell +4
We are using HST GO programs 10205, 10602, and 10898 to test the stellar upper mass limit in the solar vicinity by attempting to detect optical close companions, thus lowering the…
Optically observable zero-age main-sequence O stars
Nolan R. Walborn
A list of 50 optically observable O stars that are likely on or very near the ZAMS is presented. They have been selected on the basis of five distinct criteria, although some of th…
Pismis 24-1: The Stellar Upper Mass Limit Preserved
J. Maíz Apellániz, Nolan R. Walborn, N. I. Morrell +2
Is there a stellar upper mass limit? Recent statistical work seems to indicate that there is and that it is in the vicinity of 150 solar masses. In this paper we use HST and ground…