JULY 21 - 25, 2014


Noon: Solar, Stellar, and Planetary Sciences Division Seminar. "Biosignatures, the Case of Habitable Planets Around M Dwarfs," Antigona Segura, Universidad Nacional Autonoma de Mexico. Pratt Conference Room.

Abstract: M dwarfs are the most numerous of the parent stars for potentially habitable planets. They are also the stars around which it is easiest to detect a rocky planet using the radial velocity method with instruments on the ground. However, the UV chromospheric emission of these stars represents an interesting problem for the characterization of the atmosphere of a habitable planet. In this talk I will present the characteristics of M dwarfs, the conditions required for surface habitability, the concept of biosignatures, and the latest challenges to identify potential biosignatures on habitable planets around these stars.


12:30 pm: High Energy Astrophysics Division Lunch Talk. "Classification of Magnetized Star-Planet Interactions: Dynamics and Observational Relevance," Titos Matsakos, University of Chicago. Pratt Conference Room.

Abstract: Stellar irradiation is believed to drive outflows from the surface of close-in planets, a phenomenon that is supported by transit observations of Hot Jupiters. Assuming planetary magnetospheres similar to those of our solar system, such outflows are expected to be magnetized. On the other hand, the environment of short period orbits consists of the sweeping stellar wind plasma that is known to attain super-sonic velocities. This framework suggests the manifestation of complex magnetized star-planet interactions in systems harboring Hot Jupiters. In this work, we provide a classification of the different types of interactions that may occur, by performing a parametric study of a series of 3D mangeto-hydrodynamic numerical simulations. We incorporate stellar and planetary outflows that are consistent with detailed physical models and investigate case by case the exhibited dynamics. We discuss the observational relevance of each interaction type, highlighting the features that may distinguish them in their transit signature.


4:00 pm: CfA Summer Colloquium. "Extreme Supernovae: Transient Science in the Era of Wide-Field Untargeted Surveys," Maria Drout, CfA. Preceded by refreshments at 3:30. Phillips Auditorium.

Abstract: In the past three decades, the field of time-domain astronomy has been revolutionized by advances in both detector technology and survey strategy. Consider this: SN1987A -- the closest supernova to Earth to explode in modern times -- was the first supernova discovered in year 1987 when it was seen on Feb 23rd. Now, fast forward 27 years ... during an equivalent 54-day period this past winter, more than 200 supernovae and other astronomical transients were reported. This was made possible, in part, by the advent of wide-field untargeted transient searches such as the Panoramic Survey Telescope & Rapid Response System (Pan-STARRS1) and the Palomar Transient Factory (PTF). In this talk I will give a brief overview of the history of transient discovery and how modern transient searches are carried out, and then discuss two significant scientific advances that have come out of these surveys: (1) the construction of large, statistical, samples of known types of transients and (2) the discovery of rare classes of previously unknown transients such as superluminous supernovae, rapidly evolving supernovae, and tidal disruption events.


12:30 pm: Radio and Geoastronomy Division Weekly Lunch Talk. "Spectroscopic Receivers for the LMT," Gopal Narayanan, University of Massachusetts. Room M-340, 160 Concord Avenue.

Abstract: The Large Millimeter Telescope (LMT) is a joint project of the Instituto Nacional de Astrofmsica, Optica y Electrsnica (INAOE) in Mexico and the University of Massachusetts (UMass) to build a 50m-diameter millimeter-wave telescope. The LMT is situated atop Vulcan Sierra Negra at an altitude of 4600 m in the state of Puebla in Mexico. I will summarize the current status of the telescope and the last two years of scientific observations with the Redshift Search Receiver (RSR), a novel broadband 3mm receiver built to determine the unknown redshifts of high redshift galaxies, and the 1mm wavelength AzTEC continuum camera which is a mapping instrument. The LMT is currently operational, and I will highlight some of the ongoing scientific observations. I will also summarize new receivers that are being developed for the LMT, including (1) a novel phased focal plane array receiver that augurs a new era of radio astronomical instrumentation, (2) new 1mm VLBI receivers being built for the EHT project, and (3) a new generation 1mm focal plane array receiver for the LMT.