March 1, 2022

Speaker: Suvrath Mahadevan (in-person)

Contact Information: suvrath@astro.psu.edu

Title: Pathways to Earth-Mass Planets with Precision Spectroscopy

Abstract: Modern astronomical spectrometers are approaching the exquisite sensitivity to detect the signature of an Earth-mass planet around stars like the Sun. I shall discuss the challenges involved in making these difficult measurements with the Doppler radial velocity technique, and the evolution of the design of these instruments as they seek ever-tighter control of environmental parameters, and increased measurement precision. A suite of new technologies like frequency stabilized laser combs, low drift etalons, and deeper understanding of the detectors is enabling a new level of precision in radial velocity measurements - as well as illustrating new challenges. I will use two such instruments we have built to illustrate some of the underlying physics and measurement challenges. I will then discuss how the stars themselves are the remaining challenge, as magnetically driven processes create ‘stellar activity’ noise that can masquerade as planets and obfuscate their detection. I shall highlight a few paths we are exploring to mitigate this – using our star, the Sun, as a guide, and discuss whether the goal of discovering and characterizing terrestrial mass planets capable of hosting liquid water on their surfaces is now within reach.

Visitor's room: 125

Visit Schedule:

Tuesday (1 Mar. 2022):

  • 9:00 a.m.: Chris Spalding (Peyton 128)

  • 9:30 a.m.:

  • 10:00 a.m.: Michael Strauss (113)

  • 10:30 a.m.: Preparation for the Colloquium

  • 11:00 a.m.: Colloquium

  • 12:30 p.m.: Bahcall Lunch

  • 2:00 p.m.: Tansu Daylan (125)

  • 2:30 p.m.: Samuel Yee (017 -- basement)

  • 3:00 p.m.: Grad Students/Grad Tea (033)

  • 3:30 p.m.: Grad Students /Grad Tea (033)

  • 4:00 p.m.: Dan Tamayo (110)

  • 4:30 p.m.: Robert Lupton

  • 5:00 p.m.: Allison Strom (125)

  • 5:30 p.m.: Sarah Millholland (125)

  • 6:00 p.m.: DINNER - meet in Grand Central

Dinner Sign-up - add your name here:

  1. Suvrath Mahadevan

  2. Faculty host: Robert Lupton

  3. Postdoc host: Guðmundur Stefánsson [unfortunately can not join dinner tonight, so someone can take my spot]

  4. Sam Yee

  5. Tansu Daylan

  6. Gaspar Bakos

  7. Sarah Millholland (but happy to give the spot to a student)

  8. Nadia Zakamska

PLEASE NO MORE THAN 8 PEOPLE (it is more difficult to properly interact with the speaker with larger groups). STUDENTS HAVE PRIORITY.