Most massive stars live with a close companion and often exchange matter during their lives. We use SDSS-V spectra to map how common these companions are and to find unusual systems—some of which could be the ancestors of the black-hole and neutron-star mergers seen in gravitational waves.
Overview
Massive stars rarely live alone. Because many orbit each other closely, they can pull material from one another; these interactions set up the systems that later become pairs of black holes or neutron stars. With SDSS-V we observe each star several times and look for small shifts in their spectral lines. Those shifts reveal hidden companions and let us measure how frequent binaries are across different masses, ages, environments and metallicities. From these data we flag special cases—like stars that have been stripped by a companion or candidates that may host a black hole—and then follow them with high-resolution spectroscopy to confirm their nature. Seeing these “in-between” stages helps us connect everyday massive binaries to the gravitational-wave sources detected today.
At a glance
• Role: Leading author on the multiplicity of OBA stars
• Data: SDSS-V mwm_ob_core, three epochs per star
• Telescope instrument: The Sloan Foundation 2.5m Telescope at Apache Point Observatory / The Irénée du Pont Telescope at Las Campanas Observatory. BOSS spectrographs • Method: Radial-velocity changes to identify close binaries and interaction products
• Follow-up: High-resolution spectroscopy of top candidates
• Goal: Constrain how massive binaries evolve toward GW-source progenitors
My contributions
- 01.2024 - present: SDSS-V Collaboration Council (MPIA representative): membership and policy reviews; architect/external-collaborator applications; support for collaboration meetings and guidelines.
- Organised the 2025 collaboration meeting in Heidelberg (LOC chair; SOC member).
- Lead author on the first multiplicity paper (in prep).
Key results (so far)
- Zari, Villaseñor, Kounkel, Rix, et al. (2025). “The large-scale kinematics of young stars in the Milky Way disc: first results from SDSS-V”. (Subm. to A&A)
All SDSS-V publication
2025
- SDSS Collaboration; Gautham Adamane Pallathadka; Mojgan Aghakhanloo; James Aird; Andrés Almeida; Singh Amrita; Friedrich Anders; Scott F. Anderson; and 204 authors, including Jaime Villaseñor (2025)
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SDSS Collaboration; Gautham Adamane Pallathadka; Mojgan Aghakhanloo; James Aird; Andrés Almeida; Singh Amrita; Friedrich Anders; Scott F. Anderson; Stefan Arseneau; Consuelo González Avila; Shir Aviram; Catarina Aydar; Carles Badenes; Jorge K. Barrera-Ballesteros; Franz E. Bauer; Aida Behmard; Michelle Berg; F. Besser; Christian Moni Bidin; Dmitry Bizyaev; Guillermo Blanc; Michael R. Blanton; Jo Bovy; William Nielsen Brandt; Joel R. Brownstein; Johannes Buchner; Esra Bulbul; Joseph N. Burchett; Leticia Carigi; Joleen K. Carlberg; Andrew R. Casey; Priyanka Chakraborty; Julio Chanamé; Vedant Chandra; Cristina Chiappini; Igor Chilingarian; Johan Comparat; Kevin Covey; Nicole Crumpler; Katia Cunha; Elena D'Onghia; Xinyu Dai; Jeremy Darling; Megan Davis; Nathan De Lee; Niall Deacon; José Eduardo Méndez Delgado; Sebastian Demasi; Mariia Demianenko; Delvin Demke; John Donor; Niv Drory; Monica Alejandra Villa Durango; Tom Dwelly; Oleg Egorov; Evgeniya Egorova; Kareem El-Badry; Mike Eracleous; Xiaohui Fan; Emily Farr; Douglas P. Finkbeiner; Logan Fries; Peter Frinchaboy; Nicola Pietro Gentile Fusillo; Luis Daniel Serrano Félix; Boris Gaensicke; Emma Galligan; Pablo García; Joseph Gelfand; Katie Grabowski; Eva Grebel; Paul J Green; Hannah Greve; Catherine Grier; Emily Griffith; Paloma Guetzoyan; Pramod Gupta; Zoe Hackshaw; Patrick B. Hall; Keith Hawkins; Viola Hegedűs; Saskia Hekker; T. M. Herbst; J. J. Hermes; Lorena Hernández-García; Pranavi Hiremath; David W Hogg; Jon Holtzman; Keith Horne; Danny Horta; Yang Huang; Brian Hutchinson; Maximilian Häberle; Hector Javier Ibarra-Medel; Alexander P. Ji; Paula Jofre; James W. Johnson; Jennifer Johnson; Evelyn J. Johnston; Mary Kaldor; Ivan Katkov; Arman Khalatyan; Sergey Khoperskov; Ralf Klessen; Matthias Kluge; Anton M. Koekemoer; Juna A. Kollmeier; Marina Kounkel; Kathryn Kreckel; Dhanesh Krishnarao; Mirko Krumpe; Ivan Lacerna; Chervin Laporte; Sebastien Lepine; Jing Li; Fu-Heng Liang; Guilherme Limberg; Xin Liu; Sarah Loebman; Knox Long; Yuxi Lu; Madeline Lucey; Alejandra Z. Lugo-Aranda; Mary Loli Martínez Martinez-Aldama; Kevin McKinnon; Ilija Medan; Andrea Merloni; Sean Morrison; Natalie Myers; Szabolcs Mészáros; Johanna Müller-Horn; Samir Nepal; Melissa Ness; David Nidever; Christian Nitschelm; Audrey Oravetz; Jonah Otto; Kaike Pan; Facundo Pérez Paolino; Castalia Alenka Negrete Peñaloza; Marc Pinsonneault; Manuchehr Taghizadeh Popp; Adrian Price-Whelan; Nadiia Pulatova; Anna Barbara Queiroz; Jordan Raddick; Amy Rankine; Hans-Walter Rix; Carlos Román-Zúñiga; Daniela Fernández Rosso; Jessie Runnoe; Serat Mahmud Saad; Mara Salvato; Sebastian F. Sanchez; Natascha Sattler; Andrew Saydjari; Conor Sayres; Kevin Schlaufman; Donald P. Schneider; Axel Schwope; Lucas M. Seaton; Rhys Seeburger; Javier Serna; Sanjib Sharma; Yue Shen; Amaya Sinha; Brian Sizemore; Marzena Sniegowska; Yingyi Song; Diogo Souto; Keivan Stassun; Matthias Steinmetz; Zachary Stone; Alexander Stone-Martinez; Guy S. Stringfellow; Aurora Mata Sánchez; José Sánchez-Gallego; Jonathan Tan; Jamie Tayar; Riley Thai; Ani Thakar; Pierre Thibodeaux; Yuan-Sen Ting; Andrew Tkachenko; Benny Trakhtenbrot; Jose G. Fernandez Trincado; Nicholas Troup; Jonathan R. Trump; Natalie Ulloa; Roeland P. Van der Marel; Pablo Vera; Sandro Villanova; Jaime Villaseñor; Ji Wang; Zachary Way; Anne-Marie Weijmans; Adam Wheeler; John C. Wilson; Aida Wofford; Tony Wong; Qiaoya Wu; Dominika Wylezalek; Xiang-Xiang Xue; Renbin Yan; Qian Yang; Nadia Zakamska; Eleonora Zari; Gail Zasowski; Grisha Zeltyn; Zheng Zheng; Catherine Zucker; Rodolfo de J. Zermeño - Juna A. Kollmeier; Hans-Walter Rix; Conny Aerts; James Aird; Pablo Vera Alfaro; Andrés Almeida; Scott F. Anderson; Óscar Jiménez Arranz; and 212 authors, including Jaime Villaseñor (2025)
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Juna A. Kollmeier; Hans-Walter Rix; Conny Aerts; James Aird; Pablo Vera Alfaro; Andrés Almeida; Scott F. Anderson; Óscar Jiménez Arranz; Stefan M. Arseneau; Roberto Assef; Shir Aviram; Catarina Aydar; Carles Badenes; Avrajit Bandyopadhyay; Kat Barger; Robert H. Barkhouser; Franz E. Bauer; Chad Bender; Felipe Besser; Binod Bhattarai; Pavaman Bilgi; Jonathan Bird; Dmitry Bizyaev; Guillermo A. Blanc; Michael R. Blanton; John Bochanski; Jo Bovy; Christopher Brandon; William Nielsen Brandt; Joel R. Brownstein; Johannes Buchner; Joseph N. Burchett; Joleen Carlberg; Andrew R. Casey; Lesly Castaneda-Carlos; Priyanka Chakraborty; Julio Chanamé; Vedant Chandra; Brian Cherinka; Igor Chilingarian; Johan Comparat; Maren Cosens; Kevin Covey; Jeffrey D. Crane; Nicole R. Crumpler; Katia Cunha; Tim Cunningham; Xinyu Dai; Jeremy Darling; James W. Davidson, Jr.; Megan C. Davis; Nathan De Lee; Niall Deacon; José Eduardo Méndez Delgado; Sebastian Demasi; Mariia Demianenko; Mark Derwent; Elena D'Onghia; Francesco Di Mille; Bruno Dias; John Donor; Niv Drory; Tom Dwelly; Oleg Egorov; Evgeniya Egorova; Kareem El-Badry; Mike Engelman; Mike Eracleous; Xiaohui Fan; Emily Farr; Logan Fries; Peter Frinchaboy; Cynthia S. Froning; Boris T. Gänsicke; Pablo García; Joseph Gelfand; Nicola Pietro Gentile Fusillo; Simon Glover; Katie Grabowski; Eva K. Grebel; Paul J Green; Catherine Grier; Pramod Gupta; Aidan C. Gray; Maximilian Häberle; Patrick B. Hall; Randolph P. Hammond; Keith Hawkins; Albert C. Harding; Viola Hegedűs; Tom Herbst; J. J. Hermes; Paola Rodríguez Hidalgo; Thomas Hilder; David W Hogg; Jon A. Holtzman; Danny Horta; Yang Huang; Hsiang-Chih Hwang; Hector Javier Ibarra-Medel; Julie Imig; Keith Inight; Arghajit Jana; Alexander P. Ji; Paula Jofre; Matt Johns; Jennifer Johnson; James W. Johnson; Evelyn J. Johnston; Amy M Jones; Ivan Katkov; Anton M. Koekemoer; Marina Kounkel; Kathryn Kreckel; Dhanesh Krishnarao; Mirko Krumpe; Nimisha Kumari; Thomas Kupfer; Ivan Lacerna; Chervin Laporte; Sebastien Lepine; Jing Li; Xin Liu; Sarah Loebman; Knox Long; Alexandre Roman-Lopes; Yuxi Lu; Steven Raymond Majewski; Dan Maoz; Kevin A. McKinnon; Ilija Medan; Andrea Merloni; Dante Minniti; Sean Morrison; Natalie Myers; Szabolcs Mészáros; Kirpal Nandra; Prasanta K. Nayak; Melissa K Ness; David L. Nidever; Thomas O'Brien; Micah Oeur; Audrey Oravetz; Daniel Oravetz; Jonah Otto; Gautham Adamane Pallathadka; Povilas Palunas; Kaike Pan; Daniel Pappalardo; Rakesh Pandey; Castalia Alenka Negrete Peñaloza; Marc H. Pinsonneault; Richard W. Pogge; Manuchehr Taghizadeh Popp; Adrian M. Price-Whelan; Nadiia Pulatova; Dan Qiu; Solange Ramirez; Amy Rankine; Claudio Ricci; Jessie C. Runnoe; Sebastian Sanchez; Mara Salvato; Natascha Sattler; Andrew K. Saydjari; Conor Sayres; Kevin C. Schlaufman; Donald P. Schneider; Matthias R. Schreiber; Axel Schwope; Javier Serna; Yue Shen; Cristóbal Sifón; Amrita Singh; Amaya Sinha; Stephen Smee; Ying-Yi Song; Diogo Souto; Keivan G. Stassun; Matthias Steinmetz; Alexander Stone-Martinez; Guy Stringfellow; Amelia Stutz; José; Sá; nchez-Gallego; Jonathan C. Tan; Jamie Tayar; Riley Thai; Ani Thakar; Yuan-Sen Ting; Andrew Tkachenko; Gagik Tovmasian; Benny Trakhtenbrot; José G. Fernández-Trincado; Nicholas Troup; Jonathan Trump; Sarah Tuttle; Roeland P. van der Marel; Sandro Villanova; Jaime Villaseñor; Stefanie Wachter; Zachary Way; Anne-Marie Weijmans; David Weinberg; Adam Wheeler; John Wilson; Alessa I. Wiggins; Tony Wong; Qiaoya Wu; Dominika Wylezalek; Xiang-Xiang Xue; Qian Yang; Nadia Zakamska; Eleonora Zari; Gail Zasowski; Grisha Zeltyn; Catherine Zucker; Carlos G. Román Zúñiga; Rodolfo de J. Zermeño
