GGrantIndex
← Search

OBJECTIVES THE FIRST OBJECTIVE IS TO BETTER CHARACTERIZE KNOWN NEAR EARTH OBJECTS (NEOS) THAT HAVE SMALL APHELION DISTANCE AND TO COMPARE THESE OBJECTS TO OTHER NEOS THAT SPEND LESS TIME CLOSE TO THE SUN AND THAT ARE UNLIKELY TO HAVE HAD CLOSE ENCOUNTERS WITH EARTH OR VENUS. THE MAIN FOCUS WILL BE DETERMINATION OF LIGHT CURVES TO BETTER UNDERSTAND SHAPE. THE SECOND OBJECTIVE IS TO USE THE UNIQUE CAPABILITY THAT THE SUBARU HYPER-SUPRIMECAM OFFERS TO DISCOVER MORE NEOS WITH SMALL APHELION DISTANCE. THIS CAMERA HAS A LARGE FIELD OF VIEW AND SUBARU HAS AN 8.2-M APERTURE AND CAN MAKE SENSITIVE NEO SEARCHES AS CLOSE AS 45 DEGREES FROM THE SUN. BACKGROUND NEOS THAT HAVE SMALL APHELION DISTANCE SPEND MORE OF THEIR TIME CLOSE TO THE SUN AND THEREFORE ARE MORE LIKELY TO BE SPUN UP BY THE YARKOVSKY-O KEEFE-RADZIEVSKII-PADDACK (YORP) EFFECT. SPIN UP OF AN ASTEROID THAT HAS LOW COHESIVE FORCE CAN MODIFY ITS SHAPE. SHAPE AND ROTATION AFFECT DETECTABILITY PARTICULARLY AT SMALL PHASE ANGLE AND CAN SYSTEMATICALLY BIAS THE NUMBER OF NEOS DISCOVERED WITH SMALL APHELION DISTANCE AND MAY BIAS THE DERIVED ORBITAL DISTRIBUTION OF NEOS. ASTEROID 2015 DR215 AN ATIRA PHA (A=0.67 E=0.47 I=4 Q=0.98 H=20) PROVIDES STRONG EVIDENCE OF STRONGLY ASYMMETRIC SHAPE WITH BRIGHTNESS VARIATIONS OF AT LEAST 1 MAG. MOST NEO SEARCHES FOCUS ON OPPOSITION. PHASE EFFECTS AND HIGH AIRMASS MAKE SEARCHING FOR NEOS IN THE SWEET SPOTS DIFFICULT. NEOS WITH SMALL APHELION DISTANCE ARE DOMINANTLY LOCATED IN THE SWEET SPOTS AND ATIRA NEOS CANNOT BE DISCOVERED AT OPPOSITION. THERE ARE ONLY 16 KNOWN ATIRA NEOS.

$581,748FY2020National Aeronautics and Space AdministrationNASA

University Of Hawaii, Honolulu

Investigators

View source on USAspending →
OBJECTIVES THE FIRST OBJECTIVE IS TO BETTER CHARACTERIZE KNOWN NEAR EARTH OBJECTS (NEOS) THAT HAVE SMALL APHELION DISTANCE AND TO COMPARE THESE OBJECTS TO OTHER NEOS THAT SPEND LESS TIME CLOSE TO THE SUN AND THAT ARE UNLIKELY TO HAVE HAD CLOSE ENCOUNTERS WITH EARTH OR VENUS. THE MAIN FOCUS WILL BE DETERMINATION OF LIGHT CURVES TO BETTER UNDERSTAND SHAPE. THE SECOND OBJECTIVE IS TO USE THE UNIQUE CAPABILITY THAT THE SUBARU HYPER-SUPRIMECAM OFFERS TO DISCOVER MORE NEOS WITH SMALL APHELION DISTANCE. THIS CAMERA HAS A LARGE FIELD OF VIEW AND SUBARU HAS AN 8.2-M APERTURE AND CAN MAKE SENSITIVE NEO SEARCHES AS CLOSE AS 45 DEGREES FROM THE SUN. BACKGROUND NEOS THAT HAVE SMALL APHELION DISTANCE SPEND MORE OF THEIR TIME CLOSE TO THE SUN AND THEREFORE ARE MORE LIKELY TO BE SPUN UP BY THE YARKOVSKY-O KEEFE-RADZIEVSKII-PADDACK (YORP) EFFECT. SPIN UP OF AN ASTEROID THAT HAS LOW COHESIVE FORCE CAN MODIFY ITS SHAPE. SHAPE AND ROTATION AFFECT DETECTABILITY PARTICULARLY AT SMALL PHASE ANGLE AND CAN SYSTEMATICALLY BIAS THE NUMBER OF NEOS DISCOVERED WITH SMALL APHELION DISTANCE AND MAY BIAS THE DERIVED ORBITAL DISTRIBUTION OF NEOS. ASTEROID 2015 DR215 AN ATIRA PHA (A=0.67 E=0.47 I=4 Q=0.98 H=20) PROVIDES STRONG EVIDENCE OF STRONGLY ASYMMETRIC SHAPE WITH BRIGHTNESS VARIATIONS OF AT LEAST 1 MAG. MOST NEO SEARCHES FOCUS ON OPPOSITION. PHASE EFFECTS AND HIGH AIRMASS MAKE SEARCHING FOR NEOS IN THE SWEET SPOTS DIFFICULT. NEOS WITH SMALL APHELION DISTANCE ARE DOMINANTLY LOCATED IN THE SWEET SPOTS AND ATIRA NEOS CANNOT BE DISCOVERED AT OPPOSITION. THERE ARE ONLY 16 KNOWN ATIRA NEOS. · GrantIndex