1657 Roemera

{{Use dmy dates|date=October 2019}}

{{Infobox planet

| minorplanet = yes

| name = 1657 Roemera

| background = #D6D6D6

| image =

| image_size =

| caption =

| discovery_ref =

| discovered = 6 March 1961

| discoverer = P. Wild

| discovery_site = Zimmerwald Obs.

| mpc_name = (1657) Roemera

| alt_names = 1961 EA{{·}}1932 AB

| named_after = Elizabeth Roemer
{{small|(American astronomer)}}

| mp_category = main-belt{{·}}{{small|(inner)}}
Phocaea

| orbit_ref =

| epoch = 4 September 2017 (JD 2458000.5)

| uncertainty = 0

| observation_arc = 84.79 yr (30,971 days)

| aphelion = 2.9032 AU

| perihelion = 1.7946 AU

| semimajor = 2.3489 AU

| eccentricity = 0.2360

| period = 3.60 yr (1,315 days)

| mean_anomaly = 253.33°

| inclination = 23.372°

| asc_node = 105.32°

| arg_peri = 54.409°

| dimensions = {{val|7.665|0.219}} km
8.04 km {{small|(calculated)}}

| rotation = {{val|4.5|1}} h
{{val|34.0|0.1}} h

| albedo = 0.20 {{small|(assumed)}}
{{val|0.220|0.030}}

| spectral_type = Tholen = S{{·}}S

| abs_magnitude = 12.84{{·}}{{val|12.89|0.16}}

}}

1657 Roemera, provisional designation {{mp|1961 EA}}, is a stony Phocaea asteroid from the inner regions of the asteroid belt, approximately 8 kilometers in diameter. It was discovered on 6 March 1961, by Swiss astronomer Paul Wild at Zimmerwald Observatory near Bern, Switzerland, and later named after American astronomer Elizabeth Roemer.

Orbit and classification

Roemera is a member of the Phocaea family ({{small|701}}), a large family of stony asteroids with nearly two thousand known members.{{rp|23}} It orbits the Sun in the inner main-belt at a distance of 1.8–2.9 AU once every 3 years and 7 months (1,315 days). Its orbit has an eccentricity of 0.24 and an inclination of 23° with respect to the ecliptic. Roemera was first identified as {{mp|1932 AB}} at Heidelberg Observatory in 1932, extending the body's observation arc by 29 years prior to its official discovery observation at Zimmerwald.

Physical characteristics

In the Tholen classification, Roemera is a stony S-type asteroid.

= Lightcurves =

In May 2008, American astronomer Brian Warner obtained a rotational lightcurve of Roemera from photometric observations at his Palmer Divide Observatory in Colorado. It gave a longer than average rotation period of 34.0 hours with a brightness variation of 0.15 magnitude ({{small|U=2}}). Polish astronomer Wiesław Z. Wiśniewski found a different period solution of 4.5 hours with a low amplitude of 0.09 magnitude in March 1990 ({{small|U=2}}).

= Diameter and albedo =

According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Roemera measures 7.66 kilometers in diameter and its surface has an albedo of 0.220, while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 8.04 kilometers with an absolute magnitude of 12.89.

Naming

This minor planet was named by the discoverer in honor American astronomer Elizabeth Roemer (1929–2016), U.S. Naval Observatory, in appreciation of her untiring and successful efforts to advance the knowledge of the motions and physical properties of comets and minor planets. Roemer herself discovered the asteroids 1930 Lucifer and 1983 Bok. The official {{MoMP|1657|naming citation}} was published by the Minor Planet Center on 1 February 1965 ({{small|M.P.C. 2347}}).

References

{{reflist|30em|refs=

{{cite web

|type = 2016-10-26 last obs.

|title = JPL Small-Body Database Browser: 1657 Roemera (1961 EA)

|url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2001657

|publisher = Jet Propulsion Laboratory

|accessdate = 30 June 2017}}

{{cite book

|last = Schmadel | first = Lutz D.

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|page = 132

|date = 2007

|isbn = 978-3-540-00238-3

|doi = 10.1007/978-3-540-29925-7_1658 |chapter = (1657) Roemera }}

{{cite web

|title = 1657 Roemera (1961 EA)

|work = Minor Planet Center

|url = https://www.minorplanetcenter.net/db_search/show_object?object_id=1657

|accessdate = 24 December 2016}}

{{cite book

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|year = 2009

|url = https://archive.org/details/dictionaryminorp2008schm

|url-access = limited

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|last = Schmadel |first=Lutz D.

|publisher = Springer Berlin Heidelberg

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|isbn = 978-3-642-01964-7

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{{cite web

|title = Asteroid 1657 Roemera – Nesvorny HCM Asteroid Families V3.0

|work = Small Bodies Data Ferret

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|doi = 10.2458/azu_uapress_9780816532131-ch016

|arxiv = 1502.01628

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{{cite web

|title = LCDB Data for (1657) Roemera

|publisher = Asteroid Lightcurve Database (LCDB)

|url = http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=1657%7CRoemera

|accessdate = 24 December 2016}}

{{cite journal

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|date = November 2012

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|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2012ApJ...759L...8M

|journal = The Astrophysical Journal Letters

|volume = 759

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|bibcode = 2012ApJ...759L...8M

|doi = 10.1088/2041-8205/759/1/L8

|arxiv = 1209.5794

|access-date= 24 December 2016}}

{{Cite journal

|first1 = W. Z. |last1 = Wisniewski

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|first3 = A. W. |last3 = Harris

|first4 = R. S. |last4 = McMillan

|date = March 1995

|title = Photoelectric Observations of 125 Asteroids

|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=1995LPI....26.1511W

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|volume = 26

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|access-date= 24 December 2016}}

{{Cite journal

|author = Warner, Brian D.

|date = January 2009

|title = Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2008 May - September

|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2009MPBu...36....7W

|journal = The Minor Planet Bulletin

|volume = 36

|issue = 1

|pages = 7–13

|issn = 1052-8091

|bibcode = 2009MPBu...36....7W

|access-date= 24 December 2016}}

{{Cite journal

|first1 = Petr |last1 = Pravec

|first2 = Alan W. |last2 = Harris

|first3 = Peter |last3 = Kusnirák

|first4 = Adrián |last4 = Galád

|first5 = Kamil |last5 = Hornoch

|date = September 2012

|title = Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations

|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2012Icar..221..365P

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|issue = 1

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|bibcode = 2012Icar..221..365P

|doi = 10.1016/j.icarus.2012.07.026

|access-date= 24 December 2016}}

}}