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Isotopes of titanium
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<h2 id="list-of-isotopes">List of isotopes</h2> <table><tbody><tr><th rowspan="2">Nuclide<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a></th><th rowspan="1"><a href="/facts/Atomic_number/bgAr581S"><i>Z</i></a></th><th rowspan="1"><a href="/facts/Neutron_number/eNtwGnVL"><i>N</i></a></th><th rowspan="1"><a href="/facts/Atomic_mass/J1FJY9MV">Isotopic mass</a> (<a href="/facts/Dalton_(unit)/IMATU3vf">Da</a>)<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a><a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a><a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a></th><th rowspan="2"><a href="/facts/Half-life/kGVH8BAB">Half-life</a><a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a><a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a></th><th rowspan="2"><a href="/facts/Decay_mode/Ya6FVjt4">Decaymode</a><a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a><a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a></th><th rowspan="2"><a href="/facts/Decay_product/hT0obfLv">Daughterisotope</a><a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a></th><th rowspan="2"><a href="/facts/Spin_(particle_physics)/4Jvp7e8P">Spin</a> and<a href="/facts/Parity_(physics)/emSbJ4hD">parity</a><a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a><a class="footnote-ref" id="fnref:14" href="#fn:14"><sup>14</sup></a><a class="footnote-ref" id="fnref:15" href="#fn:15"><sup>15</sup></a></th><th colspan="2"><a href="/facts/Natural_abundance/dGjaAwc9">Natural abundance</a> (mole fraction)</th></tr><tr><th colspan="3">Excitation energy</th><th>Normal proportion<a class="footnote-ref" id="fnref:16" href="#fn:16"><sup>16</sup></a></th><th>Range of variation</th></tr><tr><td rowspan="3">39Ti</td><td rowspan="3">22</td><td rowspan="3">17</td><td rowspan="3">39.00268(22)#</td><td rowspan="3">28.5(9) ms</td><td><a href="/facts/Beta_decay/vxTBlckp">β+</a>, <a href="/facts/Proton_emission/9zxVkBkp">p</a> (93.7%)</td><td>38Ca</td><td rowspan="3">3/2+#</td><td rowspan="3"></td><td rowspan="3"></td></tr><tr><td>β+ (~6.3%)</td><td>39Sc</td></tr><tr><td>β+, 2p (?%)</td><td>37K</td></tr><tr><td rowspan="2">40Ti</td><td rowspan="2">22</td><td rowspan="2">18</td><td rowspan="2">39.990345(73)</td><td rowspan="2">52.4(3) ms</td><td>β+, p (95.8%)</td><td>39Ca</td><td rowspan="2">0+</td><td rowspan="2"></td><td rowspan="2"></td></tr><tr><td>β+ (4.2%)</td><td>40Sc</td></tr><tr><td rowspan="2">41Ti</td><td rowspan="2">22</td><td rowspan="2">19</td><td rowspan="2">40.983148(30)</td><td rowspan="2">81.9(5) ms</td><td>β+, p (91.1%)</td><td>40Ca</td><td rowspan="2">3/2+</td><td rowspan="2"></td><td rowspan="2"></td></tr><tr><td>β+ (8.9%)</td><td>41Sc</td></tr><tr><td>42Ti</td><td>22</td><td>20</td><td>41.97304937(29)</td><td>208.3(4) ms</td><td>β+</td><td>42Sc</td><td>0+</td><td></td><td></td></tr><tr><td>43Ti</td><td>22</td><td>21</td><td>42.9685284(61)</td><td>509(5) ms</td><td>β+</td><td>43Sc</td><td>7/2−</td><td></td><td></td></tr><tr><td>43m1Ti</td><td colspan="3">313.0(10) keV</td><td>11.9(3) μs</td><td><a href="/facts/Isomeric_transition/L8DHcqnk">IT</a></td><td>43Ti</td><td>(3/2+)</td><td></td><td></td></tr><tr><td>43m2Ti</td><td colspan="3">3066.4(10) keV</td><td>556(6) ns</td><td>IT</td><td>43Ti</td><td>(19/2−)</td><td></td><td></td></tr><tr><td>44Ti</td><td>22</td><td>22</td><td>43.95968994(75)</td><td>59.1(3) y</td><td><a href="/facts/Electron_capture/EIccoV1u">EC</a></td><td>44Sc</td><td>0+</td><td></td><td></td></tr><tr><td>45Ti</td><td>22</td><td>23</td><td>44.95812076(90)</td><td>184.8(5) min</td><td>β+</td><td>45Sc</td><td>7/2−</td><td></td><td></td></tr><tr><td>45mTi</td><td colspan="3">36.53(15) keV</td><td>3.0(2) μs</td><td>IT</td><td>45Ti</td><td>3/2−</td><td></td><td></td></tr><tr><td>46Ti</td><td>22</td><td>24</td><td>45.952626356(97)</td><td colspan="3">Stable</td><td>0+</td><td>0.0825(3)</td><td></td></tr><tr><td>47Ti</td><td>22</td><td>25</td><td>46.951757491(85)</td><td colspan="3">Stable</td><td>5/2−</td><td>0.0744(2)</td><td></td></tr><tr><td>48Ti</td><td>22</td><td>26</td><td>47.947940677(79)</td><td colspan="3">Stable</td><td>0+</td><td>0.7372(3)</td><td></td></tr><tr><td>49Ti</td><td>22</td><td>27</td><td>48.947864391(84)</td><td colspan="3">Stable</td><td>7/2−</td><td>0.0541(2)</td><td></td></tr><tr><td>50Ti</td><td>22</td><td>28</td><td>49.944785622(88)</td><td colspan="3">Stable</td><td>0+</td><td>0.0518(2)</td><td></td></tr><tr><td>51Ti</td><td>22</td><td>29</td><td>50.94660947(52)</td><td>5.76(1) min</td><td>β−</td><td>51V</td><td>3/2−</td><td></td><td></td></tr><tr><td>52Ti</td><td>22</td><td>30</td><td>51.9468835(29)</td><td>1.7(1) min</td><td>β−</td><td>52V</td><td>0+</td><td></td><td></td></tr><tr><td>53Ti</td><td>22</td><td>31</td><td>52.9496707(31)</td><td>32.7(9) s</td><td>β−</td><td>53V</td><td>(3/2)−</td><td></td><td></td></tr><tr><td>54Ti</td><td>22</td><td>32</td><td>53.950892(17)</td><td>2.1(10) s</td><td>β−</td><td>54V</td><td>0+</td><td></td><td></td></tr><tr><td>55Ti</td><td>22</td><td>33</td><td>54.955091(31)</td><td>1.3(1) s</td><td>β−</td><td>55V</td><td>(1/2)−</td><td></td><td></td></tr><tr><td>56Ti</td><td>22</td><td>34</td><td>55.95768(11)</td><td>200(5) ms</td><td>β−</td><td>56V</td><td>0+</td><td></td><td></td></tr><tr><td>57Ti</td><td>22</td><td>35</td><td>56.96307(22)</td><td>95(8) ms</td><td>β−</td><td>57V</td><td>5/2−#</td><td></td><td></td></tr><tr><td>58Ti</td><td>22</td><td>36</td><td>57.96681(20)</td><td>55(6) ms</td><td>β−</td><td>58V</td><td>0+</td><td></td><td></td></tr><tr><td>59Ti</td><td>22</td><td>37</td><td>58.97222(32)#</td><td>28.5(19) ms</td><td>β−</td><td>59V</td><td>5/2−#</td><td></td><td></td></tr><tr><td>59mTi</td><td colspan="3">108.5(5) keV</td><td>615(11) ns</td><td>IT</td><td>59Ti</td><td>1/2−#</td><td></td><td></td></tr><tr><td>60Ti</td><td>22</td><td>38</td><td>59.97628(26)</td><td>22.2(16) ms</td><td>β−</td><td>60V</td><td>0+</td><td></td><td></td></tr><tr><td>61Ti</td><td>22</td><td>39</td><td>60.98243(32)#</td><td>15(4) ms</td><td>β−</td><td>61V</td><td>1/2−#</td><td></td><td></td></tr><tr><td>61m1Ti</td><td colspan="3">125.0(5) keV</td><td>200(28) ns</td><td>IT</td><td>61Ti</td><td>5/2−#</td><td></td><td></td></tr><tr><td>61m2Ti</td><td colspan="3">700.1(7) keV</td><td>354(69) ns</td><td>IT</td><td>61Ti</td><td>9/2+#</td><td></td><td></td></tr><tr><td>62Ti</td><td>22</td><td>40</td><td>61.98690(43)#</td><td>9# ms[>620 ns]</td><td></td><td></td><td>0+</td><td></td><td></td></tr><tr><td>63Ti</td><td>22</td><td>41</td><td>62.99371(54)#</td><td>10# ms[>620 ns]</td><td></td><td></td><td>1/2−#</td><td></td><td></td></tr><tr><td>64Ti</td><td>22</td><td>42</td><td>63.99841(64)#</td><td>5# ms[>620 ns]</td><td></td><td></td><td>0+</td><td></td><td></td></tr><tr><th colspan="20"><i>This table header & footer:</i> <ul><li>view</li></ul></th></tr></tbody></table> <h2 id="titanium-44">Titanium-44</h2> <p>Titanium-44 (44Ti) is a radioactive isotope of titanium that undergoes <a href="/facts/Electron_capture/EIccoV1u">electron capture</a> to an <a href="/facts/Nuclear_isomer/L8DHcqnk">excited state</a> of <a href="/facts/Scandium-44/kzJ60NX3">scandium-44</a> with a half-life of 60 years, before the ground state of 44Sc and ultimately 44Ca are populated.<a class="footnote-ref" id="fnref:17" href="#fn:17"><sup>17</sup></a> Because titanium-44 can only decay through electron capture, its half-life increases with its ionization state and it becomes stable in its <a href="/facts/Fully_ionized/3lNSGJNd">fully ionized</a> state (that is, having a charge of +22).<a class="footnote-ref" id="fnref:18" href="#fn:18"><sup>18</sup></a> </p><p>Titanium-44 is produced in relative abundance in the <a href="/facts/Alpha_process/S8cf71rL">alpha process</a> in <a href="/facts/Stellar_nucleosynthesis/qEQJdJe6">stellar nucleosynthesis</a> and the early stages of <a href="/facts/Supernova/Pfo2J23l">supernova</a> explosions.<a class="footnote-ref" id="fnref:19" href="#fn:19"><sup>19</sup></a> It is produced when <a href="/facts/Calcium-40/YhuBa6LI">calcium-40</a> fuses with an <a href="/facts/Alpha_particle/dzNMs9WP">alpha particle</a> (<a href="/facts/Helium-4/vNsL5qhC">helium-4</a> nucleus) in a star's high-temperature environment; the resulting 44Ti nucleus can then fuse with another alpha particle to form chromium-48. The age of supernovae may be determined through measurements of <a href="/facts/Gamma_ray/5Drf913J">gamma-ray</a> emissions from titanium-44 and its abundance.<a class="footnote-ref" id="fnref:20" href="#fn:20"><sup>20</sup></a> It was observed in the <a href="/facts/Cassiopeia_A/wqKS2fqb">Cassiopeia A</a> supernova remnant and <a href="/facts/SN_1987A/zHyoUpBC">SN 1987A</a> at a relatively high concentration, a consequence of delayed decay resulting from ionizing conditions.<a class="footnote-ref" id="fnref:21" href="#fn:21"><sup>21</sup></a><a class="footnote-ref" id="fnref:22" href="#fn:22"><sup>22</sup></a> </p> <h2 id="see-also">See also</h2> <p>Daughter products other than titanium </p> <ul><li><a href="/facts/Isotopes_of_vanadium/R4BEw3I9">Isotopes of vanadium</a></li> <li><a href="/facts/Isotopes_of_scandium/avIUruhT">Isotopes of scandium</a></li> <li><a href="/facts/Isotopes_of_calcium/YhuBa6LI">Isotopes of calcium</a></li> <li><a href="/facts/Isotopes_of_potassium/xxMtp7JP">Isotopes of potassium</a></li></ul> <ul><li>Isotope masses from: <ul><li>Audi, Georges; Bersillon, Olivier; Blachot, Jean; <a href="/facts/Aaldert_Wapstra/9Ylvt18s">Wapstra, Aaldert Hendrik</a> (2003), <a href="https://hal.archives-ouvertes.fr/in2p3-00020241/document">"The NUBASE evaluation of nuclear and decay properties"</a>, <i>Nuclear Physics A</i>, 729: 3–128, <a href="/facts/Bibcode_(identifier)/9HtdQSGB">Bibcode</a>:<a href="https://ui.adsabs.harvard.edu/abs/2003NuPhA.729....3A">2003NuPhA.729....3A</a>, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1016%2Fj.nuclphysa.2003.11.001">10.1016/j.nuclphysa.2003.11.001</a></li></ul></li> <li>Isotopic compositions and standard atomic masses from: <ul><li><a href="/facts/John_Robert_de_Laeter/jYQj55GI">de Laeter, John Robert</a>; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). <a href="https://doi.org/10.1351%2Fpac200375060683">"Atomic weights of the elements. Review 2000 (IUPAC Technical Report)"</a>. <i><a href="/facts/Pure_and_Applied_Chemistry/9QdCDKxf">Pure and Applied Chemistry</a></i>. 75 (6): 683–800. <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1351%2Fpac200375060683">10.1351/pac200375060683</a>.</li> <li>Wieser, Michael E. (2006). <a href="https://doi.org/10.1351%2Fpac200678112051">"Atomic weights of the elements 2005 (IUPAC Technical Report)"</a>. <i><a href="/facts/Pure_and_Applied_Chemistry/9QdCDKxf">Pure and Applied Chemistry</a></i>. 78 (11): 2051–2066. <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1351%2Fpac200678112051">10.1351/pac200678112051</a>.</li></ul></li> <li><a href="http://old.iupac.org/news/archives/2005/atomic-weights_revised05.html">"News & Notices: Standard Atomic Weights Revised"</a>. <i>International Union of Pure and Applied Chemistry</i>. 19 October 2005.</li> <li>Half-life, spin, and isomer data selected from the following sources. <ul><li>Audi, Georges; Bersillon, Olivier; Blachot, Jean; <a href="/facts/Aaldert_Wapstra/9Ylvt18s">Wapstra, Aaldert Hendrik</a> (2003), <a href="https://hal.archives-ouvertes.fr/in2p3-00020241/document">"The NUBASE evaluation of nuclear and decay properties"</a>, <i>Nuclear Physics A</i>, 729: 3–128, <a href="/facts/Bibcode_(identifier)/9HtdQSGB">Bibcode</a>:<a href="https://ui.adsabs.harvard.edu/abs/2003NuPhA.729....3A">2003NuPhA.729....3A</a>, <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1016%2Fj.nuclphysa.2003.11.001">10.1016/j.nuclphysa.2003.11.001</a></li> <li><a href="/facts/National_Nuclear_Data_Center/SgVzvxLk">National Nuclear Data Center</a>. <a href="http://www.nndc.bnl.gov/nudat2/">"NuDat 2.x database"</a>. <a href="/facts/Brookhaven_National_Laboratory/L2JrG0K1">Brookhaven National Laboratory</a>.</li> <li>Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). <i><a href="/facts/CRC_Handbook_of_Chemistry_and_Physics/qjxzC2Cu">CRC Handbook of Chemistry and Physics</a></i> (85th ed.). <a href="/facts/Boca_Raton%2c_Florida/9gcNen3S">Boca Raton, Florida</a>: <a href="/facts/CRC_Press/duTuH4hz">CRC Press</a>. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-8493-0485-9.</li></ul></li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Barbalace, Kenneth L. (2006). "Periodic Table of Elements: Ti - Titanium". Retrieved 2006-12-26. <a href="http://environmentalchemistry.com/yogi/periodic/Ti-pg2.html#Nuclides" target="_blank">http://environmentalchemistry.com/yogi/periodic/Ti-pg2.html#Nuclides</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Barbalace, Kenneth L. (2006). "Periodic Table of Elements: Ti - Titanium". Retrieved 2006-12-26. <a href="http://environmentalchemistry.com/yogi/periodic/Ti-pg2.html#Nuclides" target="_blank">http://environmentalchemistry.com/yogi/periodic/Ti-pg2.html#Nuclides</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Lucier, Bryan E.G.; Huang, Yining (2016). Reviewing 47/49Ti Solid-State NMR Spectroscopy. Annual Reports on NMR Spectroscopy. Vol. 88. pp. 1–78. doi:10.1016/bs.arnmr.2015.10.001. ISBN 978-0-12-804713-2. <a href="978-0-12-804713-2" target="_blank">978-0-12-804713-2</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>mTi – Excited nuclear isomer. <a href="/wiki/Nuclear_isomer" target="_blank">/wiki/Nuclear_isomer</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits. <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p># – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS). <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae. <a href="https://www-nds.iaea.org/amdc/ame2020/NUBASE2020.pdf" target="_blank">https://www-nds.iaea.org/amdc/ame2020/NUBASE2020.pdf</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p># – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN). <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae. <a href="https://www-nds.iaea.org/amdc/ame2020/NUBASE2020.pdf" target="_blank">https://www-nds.iaea.org/amdc/ame2020/NUBASE2020.pdf</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>Modes of decay: EC:Electron capturen:Neutron emissionp:Proton emission <a href="/wiki/Electron_capture" target="_blank">/wiki/Electron_capture</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> <li id="fn:12"><p>Bold symbol as daughter – Daughter product is stable. <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li> <li id="fn:13"><p>Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae. <a href="https://www-nds.iaea.org/amdc/ame2020/NUBASE2020.pdf" target="_blank">https://www-nds.iaea.org/amdc/ame2020/NUBASE2020.pdf</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></p></li> <li id="fn:14"><p>( ) spin value – Indicates spin with weak assignment arguments. <a href="#fnref:14" class="footnote-back-ref">↩</a></p></li> <li id="fn:15"><p># – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN). <a href="#fnref:15" class="footnote-back-ref">↩</a></p></li> <li id="fn:16"><p>Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae. <a href="https://www-nds.iaea.org/amdc/ame2020/NUBASE2020.pdf" target="_blank">https://www-nds.iaea.org/amdc/ame2020/NUBASE2020.pdf</a> <a href="#fnref:16" class="footnote-back-ref">↩</a></p></li> <li id="fn:17"><p>Motizuki, Y.; Kumagai, S. (2004). "Radioactivity of the key isotope 44Ti in SN 1987A". AIP Conference Proceedings. 704 (1): 369–374. arXiv:astro-ph/0312620. Bibcode:2004AIPC..704..369M. doi:10.1063/1.1737130. <a href="/wiki/ArXiv_(identifier)" target="_blank">/wiki/ArXiv_(identifier)</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></p></li> <li id="fn:18"><p>Mochizuki, Y.; Takahashi, K.; Janka, H.-Th.; Hillebrandt, W.; Diehl, R. (2008). "Titanium-44: Its effective decay rate in young supernova remnants, and its abundance in Cas A". Astronomy and Astrophysics. 346 (3): 831–842. arXiv:astro-ph/9904378. <a href="/wiki/ArXiv_(identifier)" target="_blank">/wiki/ArXiv_(identifier)</a> <a href="#fnref:18" class="footnote-back-ref">↩</a></p></li> <li id="fn:19"><p>Fryer, C.; Dimonte, G.; Ellinger, E.; Hungerford, A.; Kares, B.; Magkotsios, G.; Rockefeller, G.; Timmes, F.; Woodward, P.; Young, P. (2011). Nucleosynthesis in the Universe, Understanding 44Ti (PDF). ADTSC Science Highlights (Report). Los Alamos National Laboratory. pp. 42–43. <a href="https://www.lanl.gov/orgs/adtsc/publications/science_highlights_2011/docs/2CosmoPDFs/fryer.pdf" target="_blank">https://www.lanl.gov/orgs/adtsc/publications/science_highlights_2011/docs/2CosmoPDFs/fryer.pdf</a> <a href="#fnref:19" class="footnote-back-ref">↩</a></p></li> <li id="fn:20"><p>Mochizuki, Y.; Takahashi, K.; Janka, H.-Th.; Hillebrandt, W.; Diehl, R. (2008). "Titanium-44: Its effective decay rate in young supernova remnants, and its abundance in Cas A". 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