Bohdan Paczynski

Bohdan Paczynski


Date of Birth
February 8, 1940
Date of Death
April 19, 2007

Bohdan “Bep” Paczynski was born in Wilno, Poland (now Vilnius, Lithuania), and educated at University of Warsaw, where he earned his Ph.D. in 1967. He worked at the Institute of Astronomy (since 1975 the Nickolas Copernicus Astronomical Center of the Polish Academy of Sciences) in Warsaw until 1982, when he moved to Princeton University, where he was the Lyman Spitzer Jr. Professor of Astrophysics. After observational studies of polarization and absorption in the Galaxy and of variable stars, he turned to theoretical work in stellar evolution and accretion disks around compact stars and in close binary systems. He wrote a widely-used stellar evolution code. He was known for theoretical work on gamma ray bursters, where he was an early proponent of the now-confirmed view that they are at cosmological distances. He proposed the use of gravitational microlensing as a technique for detecting compact objects in the galactic halo, and he was a leader of two major Polish-American sky surveys: the Optical Gravitational Lensing Experiment (OGLE) and the All-Sky Automated Survey, which is photometrically monitoring ten million stars.

Presentation of Bruce medal

Naye, Robert, Mercury 31, 4, 5 (2002).

Other awards

American Astronomical Society, Henry Norris Russell Lectureship, 2006.
American Astronomical Society High Energy Astronomy Division, Rossi Prize, 2000.
American Institute of Physics & American Astronomical Society, Dannie Heineman Prize for Astrophysics, 1992.
Association pour le Développement International de l’Observatoire de Nice, ADION medal, 1983
Astronomische Gesellschaft, Karl Schwarzschild medal, 1981, presented by T. Schmidt-Kaler, Mitteilungen der Astronomischen Gesellschaft 57, 25-26 (1982).
National Academy of Sciences, Henry Draper Medal, 1997.
Polish Physical Society, Marian Smoluchowski Medal, 2000.
Royal Astronomical Society, Eddington medal, 1987, presented by R. D. Davies, QJRAS 29, 97 (1988); Gold medal, 1999, presented Astronomy & Geophysics 41, 2, 2.6 (2000).

Biographical materials

Draine, Bruce T., Biographical Memoirs of the National Academy of Sciences, 2017.
Paczynski, Bohdan, “Gamma-ray Bursts: The Most Spectacular Fireworks,” in S. Alan Stern, ed., Our Universe: The Thrill of Extragalactic Exploration As Told by Leading Experts (Cambridge University Press, Cambridge, UK, 2001).
Preston, G.W., “Bohdan PaczyDski’s Early Years,” in K.Z. Stanek, ed., The Variable Universe: A Celebration of Bohdan Paczynski ASP Conference Series, Vol. 403, Proceedings of the Conference held 29-30 September, 2007, at Princeton University, Princeton, New Jersey, USA (Astronomical Society of the Pacific, San Francisco, 2009), pp. 15-28.
Schultz, Steven, “Paczynski ‘OGLEs’ the Sky for Answers to Cosmic Questions,” Princeton Weekly Bulletin, 15 April 2002.
Stanek, Krzysztof Z., ed., The Variable Universe: A Celebration of Bohdan Paczynski (Astronomical Society of the Pacific Conference Series, vol. 403, 2009). [contains many chapters on aspects of Paczynski’s life. Individual chapters may be downloaded.]


Boutin, Chad, Princeton University
Draine, Bruce T. & Robert H. Lupton, Physics Today 60, 10, 75-76 (2007).
Draine, Bruce T. & Jeremiah P. Ostriker, Nature 60, 447, 1064 (2007).
Dziembowski, W.A., PASP 119, 836-41 (2007).
Lasota, Jean-Pierre, Astronomy & Geophysics 48, 4.39 (2007).
Mao, Shude, “A Tribute to Bohdan Paczynski (1940-2007),” in E. Kerins, S. Mao, N. Rattenbury, & L. Wyrzykowski, eds., Proceedings of the Manchester Microlensing Conference: The 12th International Conference and ANGLES Microlensing Workshop, PoS(GMC8)002, pp. 1-4.
Maugh, Thomas H., II, Los Angeles Times, 26 April 2007
Spergel, David, Bulletin of the American Astronomical Society 39, 1077-78 (2007).


Images from the 1995 debate on the distances of gamma ray bursters

Named after him

Minor Planet #11755 Paczynski
The Alcock-Paczynski test to measure the cosmological constant


Papers, etc.

Some of Paczynski’s paper are in the Princeton University Library.

Other References: Historical

Appenzeller, Tim, “Battle is Joined over Gamma Bursts,” Science 268, 800-01 (1995).

Glanz, James, “ SCIENTIST AT WORK: BOHDAN PACZYNSKI; Finding Opportunity Where Others See Impossibility,” New York Times, 12 January 1999.

Piran, Tsvi, “Bohdan’s Impact on Our Understanding of Gamma-ray Bursts,” arXiv:0804.2074v1

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Other References: Scientific

Ginter, J., B. Paczyński, & A. Wernik, “Minima of Eclipsing Variables in 1954-1956,“ Acta Astronomica 8, 48-49 (1958).

Paczyński, B., “Dependence of the Ratio p/Av on the Density of Interstellar Matter in the Cassiopieia Region,“ Acta Astronomica 12, 206-09 (1962).

Paczynski, B., “Three-Color Observations of 2.1937 Ceti,” PASP 75, 278-80 (1963).

Paczyński, B., “Fluctuations in Interstellar Absorption from Star Counts in the Milky Way,“ Acta Astronomica 14, 157-205 (1962) [Ph.D. thesis].

Paczynski, B., “BD +30 2163, a new W UMa variable,” Astronomical Journal 69, 124-30 (1964).

Preston, George W. & Bohdan Paczynski, “Atmospheric Phenomena in the RR Lyrae Stars. I. The Singly Periodic Variables,” Ap.J. 140, 181-213 (1964).

Preston, George W., Jozef Smak, & Bohdan Paczyński, & #8220;Atmospheric Phenomena in the RR Lyrae Stars. II. The 41-Day Cycle of RR Lyrae,” Ap.J. Supp. 12, 99-161 (1965).

Paczyński, B., “Cataclysmic Variables among Binary Stars I. U Geminorum Stars,“ Acta Astronomica 15, 89-102 (1965).

Paczyński, B., “Cataclysmic Variables among Binary Stars II. Physical Parameters for Novae,“ Acta Astronomica 15, 197-210 (1965).

Herbig, G.H., G.W. Preston, J. Smak, & B. Paczyński, “The Nova-Like Variable V Sagittae as a Short-Period Eclipsing Binary,” Ap.J. 141, 617-48 (1965).

Paczyński, B., “Evolution of Close Binaries. I,“ Acta Astronomica 16, 231-47 (1966).

Paczyński, B., “Evolution of Close Binaries. II,“ Acta Astronomica 17, 1-6 (1966).

Paczyński, B. & J. Ziółkowski, “Evolution of Close Binaries. III,“ Acta Astronomica 17, 7-14 (1967).

Paczyński, B., “Evolution of Close Binaries. IV,“ Acta Astronomica 17, 193-206 (1966).

Semeniuk, I. & B. Paczyński, “Apsidal Motion in Binary Systems. III. Model Computations,” Acta Astronomica 18, 33-47 (1967).

Paczyński, B. & J. Ziółkowski, “On the Origin of Planetary Nebulae and Mira Variables,“ Acta Astronomica 18, 255-66 (1967).

Paczyński, B., “On the Mass Outflow from Stars,“ Acta Astronomica 18, 511-14 (1968).

Paczynski, B. & J. Ziółkowski, “Dynamical Instability of the Envelopes of Red Supergiants and the Origin of Planetary Nebulae,” in D.E. Osterbrock and C.R. O’Dell, eds., Planetary Nebulae, Proc. IAU Symposium no. 34 (D. Reidel, Dordrecht, 1968), pp. 396-99.

Paczyński, B., “Envelopes of Red Supergiants,“ Acta Astronomica 19, 1-22 (1969).

Paczyński, B., “Evolution of Single Stars. I. Stellar Evolution from Main Sequence to White Dwarf or Carbon Ignition,” Acta Astron. 20, 47-58 (1970).

Paczyński, B., “Evolution of Single Stars. II. Core Helium Burning in Population I Stars,” Acta Astron. 20, 195-212 (1970).

Paczyński, B., “Evolution of Single Stars. III. Stationary Shell Sources,” Acta Astron. 20, 287-309 (1970).

Paczyński, B., “Evolution of Single Stars. IV. Helium Stars,” Acta Astron. 21, 1-14 (1971).

Paczyński, B., “Evolution of Single Stars. V. Carbon Ignition in Population I Stars,” Acta Astron. 21, 271-88 (1971).

Paczyński, B., “Evolution of Single Stars. VI. Model Nuclei of Planetary Nebulae,” Acta Astron. 21, 417-35 (1971).

Paczyński, B., “Evolutionary Processes in Close Binary Systems,” Ann. Rev. Astron. & Astrophys. 9, 183-208 (1971).

Paczyński, B., “Linear Series and of Stellar Models. I. Thermal Stability of Stars,” Acta Astron. 22, 163-74 (1972).

Paczyński, B. & M. Kozłowski, “Linear Series of Stellar Models. II. Pure Carbon Stars,” Acta Astron. 22, 315-25 (1972).

Paczyński, B., “Carbon Depletion in the Envelopes of Main Sequence Stars,” Acta Astron. 23, 191-96 (1973).

Paczyński, B., “Evolutionary Aspects of Wolf-Rayet Stars,” in M.K.V. Bappu & J. Sahade, eds., Wolf-Rayet and High-Temperature Stars. Proceedings from IAU Symposium no. 49 held in Buenos Aires, Argentina, August 9-14, 1971 (D. Reidel, Dordrecht, 1973), pp. 143-63.

Trimble, V. & B. Paczyński, “Helium Red Giants,” Astron. & Astrophys. 22, 9-12 (1973).

Trimble, Virginia, B. Paczyński, & Barbara A. Zimmerman, “Evolution of Massive Population II Stars,” Astron. & Astrophys. 25, 35-40 (1973).

Bahcall, J.N., F.J. Dyson, J.I. Katz, & B. Paczyński, “Multiple Star Systems and X-Ray Sources,” Ap.J. 189, L17-L18 (1974).

Paczynski, B., “Mass of Cygnus X-1,” Astron. & Astrophys. 34, 161-62 (1974).

Paczynski, B., “Helium-Shell Flashes in Population I Stars,” Ap.J. 192, 483-85 (1974).

Paczynski, B., “Core Mass-Interflash Period Relation for Double Shell Source Stars,” Ap.J. 202, 558-60 (1975).

Paczynski, B., “Common Envelope Binaries,” in P. Eggleton, S. Mitton, & J. Whelan, eds., Structure and Evolution of Close Binary Systems; Proceedings of the Symposium, Cambridge, England, July 28-August 1, 1975 (D. Reidel, Dordrecht, 1976), pp. 75-80.

Paczyński, B., “Helium-Shell Flashes,” Ap.J. 214, 812-18 (1977).

Paczyński, B. & S.D. Tremaine, “Core Helium Flash and the Origin of CH and Carbon Stars,” Ap.J. 216, 57-60 (1977).

Paczyński, B., “A Model of Accretion Disks in Close Binaries” Ap.J. 216, 822-26 (1977).

Paczyński, B., “A Model of Selfgravitating Accretion Disk,” Acta Astron. 28, 91-109 (1978).

Paczyński, B., “A Model of Selfgravitating Accretion Disk with a Hot Corona,” Acta Astron. 28, 241-51 (1978).

Paczynski, B., “Theory of Evolution of Central Stars of Planetary Nebulae,” Planetary Nebulae; Proceedings of IAU Symposium 76, Ithaca, N.Y., June 6-10, 1977, ed. by Yervant Terzian (D. Reidel, Dordrecht, 1978), p. 201-205.

Paczynski, B. & A.N. Zytkow, “Hydrogen Shell Flashes in a White Dwarf with Mass Accretion,” Ap.J. 222, 604-11 (1978).

Alcock, Charles & B. Paczynski, “The Effect of the Heavy Element Abundance on the Evolution of Stars,” Ap.J. 223, 244-51 (1978).

Kozlowski, M., P.J. Wiita, & B. Paczyński,”Self-gravitating accretion disk models with realistic equations of state and opacities,” Acta Astron. 29, 157-76 (1979).

Alcock, Charles & B. Paczynski, “An Evolution Free Test for Non-zero Cosmological Constant,” Nature 281, 358-59 (1979).

Jaroszynski, M., M.A. Abramowicz, & B. Paczyński, “Supercritical Accretion Disks around Black Holes,” Acta Astronomica 30, 1-34 (1980).

Paczyński, B., & A. Schwarzenberg-Czerny, “Disk Accretion in U Geminorum,” Acta Astronomica 30, 127-41 (1980).

Paczyński, B. & B. Rudak, “Symbiotic Stars — Evolutionary Considerations,” Astron. & Astrophys. 82, 349-51 (1980).

Paczyński, B. & B. Rudak, “Thick Accretion Disks and Supercritical Luminosities,” Astron. & Astrophys. 88, 23-31 (1980).

Paczyński, B., & G. Bisnovatyi-Kogan, “A Model of a Thin Accretion Disk around a Black Hole,” Acta Astronomica 31, 283-91 (1981).

Paczyński, B. & R. Sienkiewicz, “Gravitational Radiation and the Evolution of Cataclysmic Binaries,” Ap.J. 248, L27-L30 (1981).

Paczyński, B. & K. Gorski, “Another Possible Case of a Gravitational Lens,” Ap.J. 248, L101-L104 (1981).

Muchotrzeb, B. & B. Paczyński, “Transonic Accretion Flow in a Thin Disk around a Black Hole,” Acta Astronomica 32, 1-11 (1982).

Paczynski, B., “Thick Accretion Disks around Black Holes,” Mitteilungen Astronomische Gesellschaft, 57, 27 (1982) [1981 Karl Schwarzschild Lecture].

Paczynski, Bohdan, “A One-Zone Model for Shell Flashes on Accreting Compact Stars,” Ap.J. 264, 282-95 (1983).

Paczynski, B., “Binary Stars,” Science 225, 275-80 (1984).

Paczynski, Bohdan, “Gravitational Microlensing at Large Optical Depth,” Ap.J. 301, 503 (1986).

Paczynski, Bohdan, “Gravitational Microlensing by the Galactic Halo,” Ap.J. 304, 1-5 (1986).

Paczynski, Bohdan, “Gamma-Ray Bursters at Cosmological Distances,” Ap.J. 308, L43-L46 (1986).

Paczynski, B., “Giant Luminous Arcs Discovered in Two Clusters of Galaxies,” Nature 325, 572-73 (1984).

Paczynski, B., “Gamma-ray Bursters at Cosmological Distances,” Ap.J., 308, L43-L46 (1986).

Paczynski, Bohdan, “A Test of the Galactic Origin of Gamma-Ray Bursts,” Ap.J. 348, 485-94 (1990).

Jaroszynski, Michal, Changbom Park, Bohdan Paczynskit, & J. Richard Gott, III, “Weak Gravitational Lensing Due to Large-Scale Structure of the Universe,” Ap.J. 365, 22-26 (1990).

Abramowicz, Marek A., Igor D. Novikov, & Bohdan Paczynski, “The Appearance of Highly Relativistic, Spherically Symmetric Stellar Winds,” Ap.J., 369, 175-78 (1991).

Paczynski, Bohdan, “Cosmological Gamma-Ray Bursts,” Acta Astronomica 41, 257-67 (1991).

Paczynski, Bohdan, “Gravitational Microlensing of the Galactic Bulge Stars,” Ap.J. 371, L63-L67 (1991).

Paczynski, Bohdan, “Estimating Redshifts for γ-Ray Bursts,” Nature 355, 521 (1992).

Mao, Shude & Bohdan Paczynski, “On the Cosmological Origin of Gamma-Ray Bursts,” Ap.J. 388, L45-L48 (1992).

Narayan, Ramesh, Bohdan Paczynski, & Tsvi Piran, “Gamma-Ray Bursts as the Death Throes of Massive Binary Stars,” Ap.J. 395, L83-L86 (1992).

Udalski, A., et al, “The Optical Gravitational Lensing Experiment. Discovery of the First Candidate Microlensing Event in the Direction of the Galactic Bulge,” Acta Astronomica 43, 289 (1993).

Paczynski, Bohdan & James E. Rhoads, “Radio Transients from Gamma-Ray Bursters,” Ap.J. 418, L5-L8 (1993).

Paczysnski, Bohdan & Guohong Xu, “Neutrino Bursts from Gamma Ray Bursts,” Ap.J. 427, 708-13 (1994).

Paczynski, Bohdan, “How Far Away Are the Gamma-Ray Bursters?” PASP 107, 1167-75 (1995).

Paczynski, Bohdan, “Studies of Gamma-Ray Bursts Time Variability,” NASA report, 1996.

Paczynski, Bohdan, et al, “Results from the Optical Gravitational Lensing Experiment (OGLE),” in Unsolved Problems of the Milky Way. Proceedings of the 169th Symposium of the International Astronomical Union, held in The Hague, The Netherlands, August 23-29, 1994, edited by Leo Blitz and Peter Teuben (Kluwer, Dordrecht, 1996).93-102.

Paczynski, Bohdan, ““Gravitational Microlensing in the Local Group,” Ann. Rev. Astron. Astrophys. 34, 419 (1996).

Mao, Shude & Bohdan Paczynski, “Mass Determination with Gravitational Microlensing,” Ap.J. 473, 57-64 (1996).

Wozniak, Przemyslaw & Bohdan Paczynski, “Microlensing of Blended Stellar Images,” Ap.J. 487, 55-60 (1997).

Paczynski, Bohdan & A. Udalski, “The Current Status and the Future of OGLE,” in Ferlet, Roger, Jean-Pierre Maillard, & Brigitte Raban, eds.,Variables Stars and the Astrophysical Returns of the Microlensing Surveys (Cedex, France, 1997), p.29.

Paczynski, Bohdan, “Gravitational Microlensing with the Space Interferometry Mission,” Ap.J. 494, L23-L26 (1998).

Paczynski, Bohdan, “Are Gamma-Ray Bursts in Star-Forming Regions?” Ap.J. 494, L45-L48 (1998).

Paczynski, B., et al, “The Optical Gravitational Lensing Experiment. UBVI Photometry of Stars in Baade's Window,” Acta Astronomica 49, 319-39 (1999).

Paczynski, Bohdan, “Monitoring All Sky for Variability [Millennium essay],” PASP 112, 1281-83 (2000).

Chen, Wen-Ping, Claudia Lemme, and Bohdan Paczynski, eds., Small-Telescope Astronomy on Global Scales : IAU Colloquium 183, proceedings of a colloquium held in Kenting, Taiwan, 4-8 January 2001 (Astronomical Society of the Pacific, San Francisco, 2001).

Paczynski, Bohdan, “Astronomy: Planetary Candidates,” Nature 411, 1002-003 (2001).

Paczynski, Bohdan, “Gamma-Ray Bursts at Low Redshift,” Acta Astronomica 51, 1-4 (2001).

Paczynski, Bohdan, “The Distance to the Magellanic Clouds,” Acta Astronomica 51, 81-89 (2001).

Paczynski, Bohdan, “Massive Variability Searches: the Past, Present and Future,” in A.J. Banday, S. Zaroubi, & M. Bartelmann, eds., Mining the Sky: Proceedings of the MPA/ESO/MPE Workshop Held at Garching, Germany, July 31 - August 4, 2000, ESO ASTROPHYSICS SYMPOSIA (Springer-Verlag, 2001).

Paczynski, Bohdan, “Gamma-Ray Burst - Supernova Relation,” in Supernovae and Gamma-Ray Bursts: the Greatest Explosions Since the Big Bang. Proceedings of the Space Telescope Science Institute Symposium, held in Baltimore, MD, USA, May 3 - 6, 1999, edited by Mario Livio, Nino Panagia, Kailash Sahu (Cambridge Univ. Press, Cambridge, UK, 2001), p. 1-8. [abstract]

Paczynski, Bohdan, “Planetary Candidates,” Nature 411, 1002-03 (2001).

Udalski, A., et al, “The Optical Gravitational Lensing Experiment. Search for Planetary and Low-Luminosity Object Transits in the Galactic Disk. Results of 2001 Campaign,” Acta Astronomica 52, 1-37 (2002).

Gehrels, N., et al, “The Swift Gamma-Ray Burst Mission,” Ap.J. 611, 1005-20 (2004).

Beaulieu, J.-P., “Discovery of a cool planet of 5.5 Earth masses through gravitational microlensing,” Nature 439, 437-40 (2006).

Paczynski, Bohdan, “Astronomy with Small Telescopes,” PASP 118, 1621-25 (2006).

Dong, Subo, et al, “First Space-Based Microlens Parallax Measurement: Spitzer Observations of OGLE-2005-SMC-001,” Ap.J. 664, 862-78 (2007).

Gaudi, B.S., et al, “Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing,” Science 319, 927-30 (2008).

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Other Works: Popularizations, Fiction, etc.

Nova program, “Death Star,” on PBS 8 January 2002 (transcript)

Paczynski, Bohdan, “Gamma-Ray Bursts—The Most Spectacular Fireworks,” In Our Universe: The Thrill of Extragalactic Exploration, As Told by Leading Experts, ed. S. Alan Stern (Cambridge University Press, Cambridge, UK, 2001), 89-106.

Paczynski, Bohdan, “A Unique Endeavor,” Sky & Telescope 95, 46 (1998).