Observa(ons of AG Pegasi by the Harvard Observing Project Jose Espinel, John A. Lewis, Rimute Terra Budreviciute, Allyson Bieryla, Lehman Garrison, Jane Huang, Andrew Vanderburg, Kate Alexander, Peter Blanchard, Theron Carmichael, SebasGan Gomez, Andrew Mayo, Melissa McIntosh, Evander Price, Sihan Yuan, Munazza K. Alam, Ian Weaver, Rodrigo Cordova Harvard University Harvard Observing Project (HOP) What is AG Pegasi? AG Pegasi is a symbioGc binary star, composed of a red The Harvard Observing Project (see supergiant and a white dwarf. The white dwarf’s luminosity is talk 314.03 by A. Bieryla and poster variable, periodically fluctuang between 400 – 3700 L☉. 240.32 by C. Schumer) engages both Between 1860 and 1870, AG Peg brightened from magnitude 9 graduate and undergraduate to 6, before gradually dimming for over a century. In 2001, students alike in learning about our Kenyon et al. proposed accreGon from the larger star as a universe. The program uses Harvard’s possible explanaon for the increases in luminosity. Consistent Clay Telescope, a 0.4m DFM design, with reports of AG Peg's 2015 outburst (Alert NoGce 521), HOP and an Apogee Alta U47 imaging CCD. observed that AG Peg had begun to brighten once more. Observaon ReducGon & Analysis - HOP observed AG Peg from September - MaximDL sorware was used for image reducGon and photometry rd th 3 , 2015, to December 10 , 2016 ß AG Pegasi AG PEG ABSOLUTE RA: 21h 51m 01.97413s - Absolute photometry was performed on the B and V filters using using Harvard's 16-inch Clay Telescope DEC: +12° 37ʹ 32.1218″ SDSS magnitudes for reference stars PHOTOMETRY (2015) B V - Observed during 2015 and 2016 Fall ß AG Pegasi - Relave photometry was performed on all filters 7.5 semesters - The light curves produced for the B, R, and V bands suggest that 8 - Over 800 images obtained the star’s luminosity has decreased since 2015 - Exposures ranged from 1-150sec 8.5 - Observaons in Bessel BVR filters AG Pegasi and reference stars 9 JULIAN DATE 9.5 AG PEG RELATIVE PHOTOMETRY AG PEG ABSOLUTE PHOTOMETRY ABSOLUTE MAGNITUDE Conclusions 10 R B V B V 2457260 2457280 2457300 2457320 -5.5 7.5 - AG Peg’s luminosity increased by approximately one magnitude -4.5 8.5 from September to October 2015 -3.5 9.5 - AG Peg’s luminosity decreased by -2.5 10.5 two magnitudes from October -1.5 11.5 2015 to December 2016 RELATIVE MAGNITUDE ABSOLUTE MAGNITUDE 12.5 - ConGnued monitoring is necessary 2457200 2457300 2457400 2457500 2457600 2457700 2457800 2457200 2457300 2457400 2457500 2457600 2457700 2457800 to determine ongoing variability JULIAN DATE JULIAN DATE References: Kenyon, ScoO J., Daniel Proga, and Charles D. Keyes. "The ConGnuing Slow Decline of AG Pegasi." The Astronomical Journal 122.1 (2001): 349-59. Web. 15 Dec. 2016. Contact Informaon Scan Poster "Clay Telescope." Harvard University Astronomy Lab and Clay Telescope. Harvard University, n.d. Web. 15 Dec. 2016. "Harvard Observing Program." Harvard University Astronomy Lab and Clay Telescope. Harvard University, n.d. Web. 15 Dec. 2016. Presenter: hOps://lh3.googleusercontent.com/-p2pv0aUoqpE/V3YvR00f7_I/AAAAAAAACP4/E18BYybF2uM/800px--ArGst%252527s_impression_of_vampire_star_OGG_thumb Jose Espinel %25255B3%25255D.jpg?imgmax=800 hp://spaceflight.nasa.gov/gallery/images/staon/crew-24/hires/iss024e013421.jpg Email: Waagen, E.O., 2015, AAVSO Alert NoGce, 521 [email protected] .