Year: 2018
Type: article
Abstract: The NASA Kepler and K2 Missions have recently revealed a population of transiting giant planets orbiting moderately evolved, low-luminosity red giant branch stars. Here, we present radial velocity (RV) measurements of three of these systems, revealing significantly non-zero orbital eccentricities in each case. Comparing these systems with the known planet population suggests that close-in giant planets around evolved stars tend to have more eccentric orbits than those around main sequence stars. We interpret this as tentative evidence that the orbits of these planets pass through a transient, moderately eccentric phase where they shrink faster than they circularize due to tides raised on evolved host stars. Additional RV measurements of currently known systems, along with new systems discovered by the recently launched NASA Transiting Exoplanet Survey Satellite (TESS) mission, may constrain the timescale and mass dependence of this process.
Institutions: University of Hawaiʻi at Mānoa, University of Hawaii System, The University of Sydney, Aarhus University, Search for Extraterrestrial Intelligence, Goddard Space Flight Center, California Institute of Technology, Leiden University, Leiden Observatory, University of California, Berkeley
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Awards: WE PROPOSE TO PERFORM A HOMOGENEOUS AND ACCURATE RE-DETERMINATION OF FUNDAMENTAL PROPERTIES OF THE FULL KEPLER TARGET SAMPLE, WITH AN EMPHASIS ON PRE, THE PROPOSAL ADDRESSES TWO MAIN K2 SCIENCE GOALS: EXOPLANET DETECTION AND STELLAR ASTROPHYSICS. DUE TO THE LOW NUMBER OF K2 SHORTCADENCE SLOTS, OUR S, IGF::OT::IGF CRESST IITHE GODDARD CENTER FOR RESEARCH AND EXPLORATION IN SPACE SCIENCE AND TECHNOLOGY (CRESST) II WILL CARRY OUT OBSERVATIONAL EXPERIMENTAL AND THEORETICAL RESEARCH IN SUPPORT OF NASA STRATEGIC SCIENCE MISSION OBJECTIVES RELATING TO:A.THE SOLAR SYSTEM STARS GALAXIES AND THE UNIVERSE AT LARGE;B.THE INFORMATIONAL AND COMPUTATIONAL SCIENCES RELATED TO THE UNIQUE NEEDS OF DATA SYSTEMS REQUIRED TO INTERPRET DATA FROM THE SPACE SCIENCES; ANDC.THE DEVELOPMENT OF THE TECHNOLOGY REQUIRED TO ACHIEVE THESE SCIENTIFIC CHALLENGES.THIS COOPERATIVE AGREEMENT WILL ALLOW FOR SUBSTANTIAL PROGRAMMATIC INVOLVEMENT IN THE FORM OF COLLABORATION BETWEEN GSFC AND THE CRESST II AS WELL AS JOINT DEVELOPMENT OF RESEARCH OBJECTIVES.THE GOAL IS TO ESTABLISH A FOCUSED PARTNERSHIP THAT:A.BRINGS TOGETHER GSFC AND EXTERNAL SCIENTISTS TO IMPLEMENT THE NASA STRATEGIC GOAL IN SPACE SCIENCE;B.BUILDS ON THE CAPABILITIES AND STRENGTHS OF PARTICIPATING ORGANIZATION IN SPACE SCIENCE;C.PROVIDES ORGANIZATION AND STAFFING FLEXIBILITY TO ADAPT TO EVOLVING RESEARCH PROGRAM NEEDS;D.INCREASES THE INVOLVEMENT OF MINORITY AND WOMEN SCIENTISTS IN SPACE SCIENCE RESEARCH; ANDE.FACILITATES ACCESS TO STUDENT TALENT AND PROVIDES OPPORTUNITIES FOR THEIR PARTICIPATION IN NASA PROGRAMS.A BROAD AND VIGOROUS SPACE RESEARCH PROGRAM IN NASA IS VITAL FOR THE ADVANCEMENT OF KNOWLEDGE. SCIENTISTS AT NASA IN COLLABORATION WITH OUTSIDE SCIENTISTS PLAY A KEY ROLE IN CONCEIVING NEW SPACE MISSIONS PROVIDING MISSION REQUIREMENTS AND ACHIEVING RESEARCH OBJECTIVES AIMED AT UNDERSTANDING THE ORIGINS STRUCTURE AND EVOLUTION OF SYSTEMS IN THE UNIVERSE AND EXPLORING THE SOLAR SYSTEM.THE CRESST II WILL FOCUS PRIMARILY ON SCIENTIFIC RESEARCH. IT IS EXPECTED TO STRENGTHEN COOPERATIVE RELATIONSHIPS BETWEEN THE RECIPIENT AND GOVERNMENT SCIENTISTS IN THE GODDARD SCIENCES AND EXPLORATION DIRECTORATE (SED) AND WILL PROVIDE A VEHICLE TO INCREASE THE INVOLVEMENT OF THE EXTERNAL SCIENCE COMMUNITY IN THE PURSUIT OF NASA GOALS.THE CRESST II WILL CONDUCT RESEARCH COLLABORATIVELY WITH ORGANIZATIONAL ELEMENTS WITHIN THE GODDARD SED (CODE 600). RESEARCH MAY INVOLVE ANALYSIS OF DATA FROM OPERATING AND PAST MISSIONS AND MODELING AND DESIGN OF MISSIONS PLANNED OR UNDER DEVELOPMENT. FUTURE RESEARCH ACTIVITIES WILL EVOLVE AS A FUNCTION OF PRIORITIES BUDGETS FUNDING OPPORTUNITIES AND SUCCESS OF PROPOSAL SUBMISSIONS., THE MOST POWERFUL TESTS OF STELLAR STRUCTURE AND EVOLUTION COME FROM THE BRIGHTEST STARS IN THE NIGHT SKY FOR WHICH COMPLEMENTARY OBSERVATIONAL TECHNIQUES (SUCH AS ASTROMETRY ASTEROSEISMOLOGY AND INTERFEROMETRY) CAN BE COMBINED. SO FAR STARS BRIGHTER THAN KP<6 MAG WERE RARELY OBSERVED WITH KEPLER/K2 DUE TO THE LARGE NUMBER OF PIXELS REQUIRED TO CAPTURE THE SATURATED PIXEL COLUMNS. WE PROPOSE K2 LONG-CADENCE OBSERVATIONS OF THE BRIGHTEST K2 STARS IN CAMPAIGNS 11-13 (INCLUDING 36 OPH THE BRIGHTEST K DWARF OBSERVABLE BY K2) USING A NOVEL TECHNIQUE WHICH USES A SMALL NUMBER OF UNSATURATED PIXELS. ASTEROSEISMIC STUDIES OF THESE TARGETS WILL ALLOW UNPRECEDENTED TESTS OF ASTEROSEISMIC SCALING RELATIONS FOR GIANTS AND INSIGHTS INTO POORLY UNDERSTOOD INTERNAL PROCESSES OF INTERMEDIATE-MASS STARS SUCH AS CONVECTIVE CORE OVERSHOOTING. WE SELECTED 54 TARGETS WITH KP<6.0 MAG FROM THE HIPPARCOS CATALOG. WE WILL USE SMALL (~20X20 PIXEL) CIRCULAR APERTURES AROUND THE SATURATED CORE FOR EACH TARGET AND PERFORM PHOTOMETRY USING WEIGHTED SUMS OF UNSATURATED PIXELS IN THE WINGS OF THE CIRCULAR APERTURE. THE METHOD (SO-CALLED HALO PHOTOMETRY) HAS BEEN DEMONSTRATED TO DETECT PULSATIONS FOR ALL BRIGHT PLEIADES AND HYADES STARS OBSERVED IN CAMPAIGN 4. WE WILL ALSO ORGANIZE SPECTROSCOPIC AND INTERFEROMETRIC FOLLOW-UP OBSERVATIONS THAT WILL BE COMBINED WITH THE K2 PHOTOMETRY. OUR PROPOSAL ADDRESSES FUNDAMENTAL STELLAR ASTROPHYSICS A KEY SCIENCE GOAL OF THE K2 MISSION. OUR PROJECT FURTHERMORE SUPPORTS GALACTIC ASTROPHYSICS ANOTHER KEY SCIENCE AREA IDENTIFIED IN THE NRA THROUGH THE CALIBRATION OF SCALING RELATIONS FOR GALACTIC ARCHEOLOGY STUDIES. A BETTER UNDERSTANDING OF STELLAR MODELS THROUGH THE STUDY OF BRIGHT STARS IS RELEVANT FOR SCIENCE GOALS PURSUED BY BOTH PRESENT AND FUTURE NASA MISSIONS SUCH AS THE CHARACTERIZATION OF EXOPLANETS (TESS JWST) AS WELL AS STELLAR POPULATIONS AND GALAXY FORMATION/EVOLUTION (HST JWST).
OpenAlex ID: W2806161550