Key, Homework #6, AST 3018, Fall 2011

# Key, Homework #6, AST 3018, Fall 2011 - £5 393.8...

This preview shows pages 1–5. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: £5? 393.8 HGMEWORK #6 QUE 11f3lli ALL 0? THESE PRGBLEMS ARﬁ FROM THE TEX? 2.3) The apparent magnitude of the Sun is —26.8. How much brighter does the Sun appear than the brightest star, which has m = ~l? {mawmﬁ/af ,mg 3: -~ at“? J M; -:». ‘t ,. .- N‘Ba my 53-, met/2,5; fa 3m ,19 \$3}? 2/ E‘E "(-2Lré’ﬂ/QMF‘M 2. 5} Show that our deﬁnittnn of magnitudes has the feiiowing property: If we have three stars with eaergy fimesnc 1} f2 and ‘3 am? we deﬁne m2 — m1— — 2 S logmm/E) and 113— mi: 2.5 iogmﬁzlfg), then m3 _ {111:2 5 §0g1{)(f1/f3} Mbwmﬁ 35333551452.) f .r mﬁvwwz; 2,5“ Eciigiygdgsk} (4 99 me: eewewe Mbwm M2»)::L% W9 >+f6§637fgj W“ ”i; .3. w w W23 W13 2.17) How does the absolute magnitude of a star vary with the size of the star (assuming the temperature stays constant)? ﬁll/f” ﬁﬁlgrylﬁﬂﬁﬁfﬁlﬁtﬂ ‘laf‘eei A; om WW \éiﬁ has: as“; R QWM m m M? Mr G :2 53056:; bl 3 all a, by: lag, Er [£1 _. rash! .1, a?” Ff.“ Gd l? sé’ElE fk T‘ﬁT’Zﬂ P "La l We 1% 3 a»? “i e eta/13 “5 W‘ L 1.." I 2%“ SGMTAJI“? by l will 61_/2~7‘ " _,., 3. f wit l? flﬂ L Mi ~42» {it}? be” by H Q‘s-Tgag‘ WET/LE? 2’ XL, 2. WWW” r“ (”a ﬁx M WWWW “30:3 «— e eat; 2.26) (a) if we can measure parallaxes as small as 0.1 arc sec, what is the greatest distance that can be measured using the method of trigonometric parallaxes? (b) By what factor will the volume of space over which we can measure parallax change if we can measure to 0.001 arc sec? (c) Why is the volume of space important? ‘9’) {330A Oll'w’l" :1 “L, x {(3 53¢. 55 {A :o,eo; alga-A" M “M 3; {maﬁa 3 1 W M W l/lw p—EEWR ﬂ/i dly Ravage)?" 23 E 3? 5 a t; teemfﬁa if; £35.53; __ ; Cla\ agiﬂézfet gigw} s, ””1 W” ”i?” ”W9; Vi ﬁvﬁhﬁtd \lef \ §' ‘ ' ee- giz-a a; 3;: Wise”? a) ﬁsgmmswrﬁe ”“ am T%EE stale. ggwgny as ,W j e: W; assets-.1 Wm: Nee/WEEK are: areas way daemmm “5? Eiﬁfiﬂfﬁt fﬁérﬂaﬁsTréﬁeﬁ “fa The: Uocuxngt ‘ WW “lessee-gees c351“ swam T’B mama we» cm; w t :«r F Mamauwm Ta “em l6 Vera magma 2.27) If we lived on Mars instead ofthe Earth, how large would the parsec be? A Pager-ac, re T'Hﬁﬂf‘ emmwme Fara mews-E {ﬁe}; 4}” w a?" 4 as? .m “rte; ﬁﬁﬁeimfﬁﬁlﬁ‘iﬂﬂﬁ; «use smerewa sea! mm {E at" l ﬂﬁﬁﬁﬁﬁ P: a”; PE” :3 6&1: fgxﬂ‘im . M: m “a,“ me 'Nh w“ W27 52.“; 45%,?” r3 ... g; —<: ' w ﬁes ' l . ”frag ash-riﬂe, metres me a? — tPQ 1% the augeﬁew ex 5', El (”We Mews Pﬁfgﬁgg}; 7; L52... E’ﬁlﬁTl’l l>ﬁﬁﬁg¥ﬁﬁ {NA 2.29) Derive an expression for the distance to a star in terms of its distance modulus. 1J5"? (jlr‘ﬂ jéis'lﬂanJCﬁ Wirﬁelmlug -; {MM/Vl- Wﬁﬂﬁ%§lﬂ%&ﬁg WwMﬁ\dMﬁfl9§Q;L; ”3 {£le 3 ﬂ 3L “3:: reﬁll/f" Oi :; moral fl 4.7) The focal length of the objective on your telescope is 0.5 m. (a) What focal length eyepiece would you have to use to have the image ofthe full Moon (whose actual size is 30 arc min) subtend an angle of 2 degrees? (b) If you then took a photograph with a 500 mm focal length camera lens, how large would the image be on the film? A) [44 3&0 .3. a {\$2, I: 2;” ’““ {3; (E). "““ {9 i) 4.13) Suppose you have a Cassegrain telescope at home, with a 0.25 m diameter primary mirror and a secondary mirror with a diameter of 5 cm. What fraction of the primary is blocked by the secondary? 3f Camus” ”it 4.29) If a radio source emits a solar luminosity (4x1033 erg/s) in radio waves, (a) What would be the power per surface area reaching us if we ‘were (i) 1 AU away, (ii) 1 pc away? (b) Ifthat power is uniformly spread out over a frequency range of 1011 Hz, what is the flux density (power/surface area/Hz) in each case? (c) How does this compare with the power you receive from a 50 kW radio station 10 km from you? :53 IQ: Li'XI’DE: :ezg/ggg a) {a} ,2: ﬂgggie 213‘, mu. ~29 ,5; a. a: ”is, M m ‘33gsw a. - . w»W%br-iw 9%, WWWQ «an {\$.33 =33 m W575 “ ‘fx/pggems/sse fi-‘cl “We. 3-3 3 O” in} W“ (a) 3: ‘ G % s u" . . a «s :2. ' L mew wwwmmwwss'“? it; “Film 3&3“ ‘3" M “,2“ i l \at “64» - i ‘22 32W) ﬂﬂmﬁefﬁ“ 3“ ‘v , \$€¥Mxﬁ Mia»? hi; ‘ M L“) ,cgwg éﬁwﬁkﬂﬁ (:9 ileﬁu @1er “ g” a 31:53:: 5‘ K g z: “ﬁg/sic WWW I???” ﬁg! if am g; _ Wgwgmm W 360 CQ‘ {\$ég 63- gas Keﬂ’ﬁ m am. “age ‘ Wit»; 2? We m £3 w 4.32) What is the total collecting area of- (a) the VLA (b) the ALMA with 75 10 m diameter telescopes? (c) For ALMA, how many 12 m diameter telescopes would you need to have the same collecting area as 75 10 m diameter telescopes? a) WA: 4'? " Team? :5: ﬁﬁfamaf ZJQWJM 53347 i L 2.3” I 2”? :cé‘ﬂm #5} :3 M‘TLE) : “2'7 WEE“); :il31330 W a V1?” M a L W m: u A :1 75W 5 ”9 lWﬁw {,Eﬁ?‘ {Q ﬁnk“ Err, \$53 {WSW 0) ﬂJ‘N‘m/M "’ Q/ﬁlb ...
View Full Document

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern