Asteroid Measurements at Millimeter Wavelengths with the South Pole Telescope

• Published in: The Astrophysical Journal
• Main Authors: Chichura, P.M., Foster, A., Patel, C., Ossa-Jaen, N., Ade, P.A.R., Ahmed, Z., Anderson, A.J., Archipley, M., Austermann, J.E., Avva, J.S., Balkenhol, L., Barry, P.S., Basu Thakur, R., Beall, J.A., Benabed, K., Bender, A.N., Benson, B.A., Bianchini, F., Bleem, L.E., Bouchet, F.R., Bryant, L., Byrum, K., Carlstrom, J.E., Carter, F.W., Cecil, T.W., Chang, C.L., Chaubal, P., Chen, G., Chiang, H.C., Cho, H.-M., Chou, T-L., Citron, R., Cliche, J.-F., Crawford, T.M., Crites, A.T., Cukierman, A., Daley, C.M., Denison, E.V., Dibert, K., Ding, J., Dobbs, M.A., Dutcher, D., Everett, W., Feng, C., Ferguson, K.R., Fu, J., Galli, S., Gallicchio, J., Gambrel, A.E., Gardner, R.W., George, E.M., Goeckner-Wald, N., Gualtieri, R., Guns, S., Gupta, N., Guyser, R., de Haan, T., Halverson, N.W., Harke-Hosemann, A.H., Harrington, N.L., Henning, J.W., Hilton, G.C., Hivon, E., Holder, G.P., Holzapfel, W.L., Hood, J.C., Howe, D., Hrubes, J.D., Huang, N., Hubmayr, J., Irwin, K.D., Jeong, O.B., Jonas, M., Jones, A., Khaire, T.S., Knox, L., Kofman, A.M., Korman, M., Kubik, D.L., Kuhlmann, S., Kuo, C.-L., Lee, A.T., Leitch, E.M., Li, D., Lowitz, A., Lu, C., Marrone, D.P., Mcmahon, J.J., Meyer, S.S., Michalik, D., Millea, M., Mocanu, L.M., Montgomery, J., Moran, C. Corbett, Nadolski, A., Natoli, T., Nguyen, H., Nibarger, J.P., Noble, G., Novosad, V., Omori, Y., Padin, S., Pan, Z., Paschos, P., Patil, S., Pearson, J., Phadke, K.A., Posada, C.M., Prabhu, K., Pryke, C., Quan, W., Rahlin, A., Reichardt, C.L., Riebel, D., Riedel, B., Rouble, M., Ruhl, J.E., Saliwanchik, B.R., Sayre, J.T., Schaffer, K.K., Schiappucci, E., Shirokoff, E., Sievers, C., Smecher, G., Sobrin, J.A., Springmann, A., Stark, A.A., Stephen, J., Story, K.T., Suzuki, A., Tandoi, C., Thompson, K.L., Thorne, B., Tucker, C., Umilta, C., Vale, L.R., Veach, T., Vieira, J.D., Wang, G., Whitehorn, N., Wu, W.L.K., Yefremenko, V., Yoon, K.W., Young, M.R.
• Other Authors: Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), SPT
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]; South Pole; South pole
• Online Access: https://hal.science/hal-03822150; https://hal.science/hal-03822150/document; https://hal.science/hal-03822150/file/Chichura_2022_ApJ_936_173.pdf; https://doi.org/10.3847/1538-4357/ac89ec

International audience <jats:title>Abstract</jats:title> <jats:p>We present the first measurements of asteroids in millimeter wavelength data from the South Pole Telescope (SPT), which is used primarily to study the cosmic microwave background (CMB). We analyze maps of two ∼270 deg<jats:sup>2</jats:sup> sky regions near the ecliptic plane, each observed with the SPTpol camera ∼100 times over 1 month. We subtract the mean of all maps of a given field, removing static sky signal, and then average the mean-subtracted maps at known asteroid locations. We detect three asteroids—(324) Bamberga, (13) Egeria, and (22) Kalliope—with signal-to-noise ratios (S/N) of 11.2, 10.4, and 6.1, respectively, at 2.0 mm (150 GHz); we also detect (324) Bamberga with an S/N of 4.1 at 3.2 mm (95 GHz). We place constraints on these asteroids’ effective emissivities, brightness temperatures, and light-curve modulation amplitude. Our flux density measurements of (324) Bamberga and (13) Egeria roughly agree with predictions, while our measurements of (22) Kalliope suggest lower flux, corresponding to effective emissivities of 0.64 ± 0.11 at 2.0 and < 0.47 at 3.2 mm. We predict the asteroids detectable in other SPT data sets and find good agreement with detections of (772) Tanete and (1093) Freda in recent data from the SPT-3G camera, which has ∼10× the mapping speed of SPTpol. This work is the first focused analysis of asteroids in data from CMB surveys, and it demonstrates we can repurpose historic and future data sets for asteroid studies. Future SPT measurements can help constrain the distribution of surface properties over a larger asteroid population.</jats:p>